Proceedings Volume 6991

Biophotonics: Photonic Solutions for Better Health Care

cover
Proceedings Volume 6991

Biophotonics: Photonic Solutions for Better Health Care

View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 29 May 2008
Contents: 12 Sessions, 62 Papers, 0 Presentations
Conference: SPIE Photonics Europe 2008
Volume Number: 6991

Table of Contents

icon_mobile_dropdown

Table of Contents

All links to SPIE Proceedings will open in the SPIE Digital Library. external link icon
View Session icon_mobile_dropdown
  • Front Matter: Volume 6991
  • Keynote Session
  • Advanced Spectroscopy and Microscopy I
  • Advanced Spectroscopy and Microscopy II
  • Advanced Spectroscopy and Microscopy III
  • Optical Coherence Tomography
  • Optical Fibers, Assays, and Sensors I
  • Optical Fibers, Assays, and Sensors II
  • Advanced Spectroscopy and Microscopy IV
  • Advanced Spectroscopy and Microscopy V
  • Photonic Therapies
  • Poster Session
Front Matter: Volume 6991
icon_mobile_dropdown
Front Matter: Volume 6991
This PDF file contains the front matter associated with SPIE Proceedings Volume 6991, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.
Keynote Session
icon_mobile_dropdown
Coherent optical imaging and guided interventions in breast cancer: translating technology into clinical applications
Breast cancer continues to be one of the most widely diagnosed forms of cancer in women and the second leading type of cancer deaths for women. The metastatic spread and staging of breast cancer is typically evaluated through the nodal assessment of the regional lymphatic system, and often this is performed during the surgical resection of the tumor mass. The recurrence rate of breast cancer is highly dependent on several factors including the complete removal of the primary tumor during surgery, and the presence of cancer cells in involved lymph nodes. Hence, developing means to more accurately resect tumor cells, along with the tumor mass, and ensure negative surgical margins, offers the potential to impact outcomes of breast cancer. The use of diffuse optical tomography has been applied for screening optical mammography applications as an alternative to standard x-ray mammography. The use of coherence ranging and coherent optical imaging in breast tissue has also found numerous applications, including intra-operative assessment of tumor margin status during lumpectomy procedures, assessment of lymph node changes for staging metastatic spread, and for guiding needle-biopsy procedures. The development, pre-clinical testing, and translation of techniques such as low-coherence interferometry (LCI) and optical coherence tomography (OCT) into clinical applications in breast cancer is demonstrated in these feasibility studies.
Advanced Spectroscopy and Microscopy I
icon_mobile_dropdown
Raman microscopic imaging of cells and applications monitoring the uptake of drug delivery systems
Christian Matthäus, Tatyana Chernenko, Luis Quintero, et al.
Raman spectroscopy, in combination with optical microscopy provides a new non-invasive method to asses and image cellular processes. Based on the spectral signatures of a cell's components, it is possible to image cellular organelles such as the nucleus, chromatin, mitochondria or lipid bodies, at the resolution of conventional microscopy. Several multivariate algorithms, for example hierarchical cluster analysis or orthogonal subspace projection, may be used to reconstruct an image of a cell. The noninvasive character of the technique, as well as the associated chemical information, may offer advantages over other imaging techniques such as fluorescence microscopy. Currently of particular interest are uptake and intracellular fate of various pharmaceutical nanocarriers, which are widely used for drug delivery purposes, including intracellular drug and gene delivery. We have imaged the uptake and distribution patterns of several carrier systems over time. In order to distinguish the species of interest from their cellular environment spectroscopically, the carrier particles or the drug load itself may be labeled with deuterium. Here, we introduce the concept of Raman imaging in combination with vertex component data analysis to follow the uptake of nanocarriers based on phospholipids as well as biodegradable polymers.
Infrared imaging for tumor detection using antibodies conjugated magnetic nanoparticles
Thermography is a well known approach for cost effective early detection of concourse tumors. However, till now - more than 5 decades after its introduction - it is not considered as a primary tool for cancer early detection, mainly because its poor performance compared to other techniques. This work offers a new thermographic approach for tumor detection which is based on the use of antibody conjugated magnetic nanoparticles ("MNP") as a tumor specific marker. Wename this method "Thermal Beacon Thermography" ("TBT"), and it has the potential to provide considerable advantages over conventional thermographic approach. TBT approach is based on the fact that MNP are producing heat when subjected to an alternating magnetic field ("AMF"). Once these particles are injected to the patient blood stream, they specifically accumulate at the tumor site, providing a local heat source at the tumor that can be activated and deactivated by external control. This heat source can be used as a "thermal beacon" in order to detect and locate tumor by detecting temperature changes at the skin surface using an IR camera and comparing them to a set of pre-calculated numerical predictions. Experiments were conducted using an in vitro tissue model together with industrial inductive heating system and an IR camera. The results shows that this approach can specifically detect small tumor phantom (D=1.5mm) which was embedded below the surface of the tissue phantom.
Advanced Spectroscopy and Microscopy II
icon_mobile_dropdown
A multitechnique study of bacteriorhodopsin's photonics toward new optical devices
Marta Martin, Marie-Belle Saab, Thierry Cloitre, et al.
Bacteriorhodopsin (BR) is a robust trans-membrane protein that functions as a light-driven proton pump, thus is an excellent candidate for biophotonics applications. For the development of new optical devices, the buildup of stable BR matrices has to be optimised. In this work, we present a multi- technique approach: the combination of optical waveguide lightmode spectroscopy (OWLS), atomic force microscopy (AFM) and multi-photon microscopy (MPM) aiming to analyze the optical and physico-chemical properties of BR embedded in polyelectrolyte multilayers (PEM) in its membrane bound form (purple membrane, PM), as well as solubilized BR immobilized within a photonic structure built of porous silicon (PSi). OWLS measurements revealed the possibility of incorporation of PM-BR layers into PE-multilayers. The calculated thickness and refractive index of the adsorbed layers demonstrate the successful adsorption of PM on top of the positively or negatively charged PE layers. Morphological studies by AFM proved a complete coverage of the positively charged PE layer with PM patches. As for the other model system, photonic responses of BR, after being immobilized within PSi substrates, have been evaluated using multi-photon microscopy. Fluorescence emission and second harmonic generation (SHG) of the BR-PSi system were observed at some particular pores of PSi and subsequent enhancement of the signal arising from the BR adsorbed within the pores was detected. Our results constitute the first steps of two interesting and innovative biomimetic approaches for the future design and development of BR based integrated optical devices.
Identification of active fluorescence stained bacteria by Raman spectroscopy
Mario Krause, Beatrice Beyer, Christian Pietsch, et al.
Microorganisms can be found everywhere e.g. in food both as useful ingredients or harmful contaminations causing food spoilage. Therefore, a fast and easy to handle analysis method is needed to detect bacteria in different kinds of samples like meat, juice or air to decide if the sample is contaminated by harmful microorganisms. Conventional identification methods in microbiology require always cultivation and therefore are time consuming. In this contribution we present an analysis approach to identify fluorescence stained bacteria on strain level by means of Raman spectroscopy. The stained bacteria are highlighted and can be localized easier against a complex sample environment e.g. in food. The use of Raman spectroscopy in combination with chemometrical methods allows the identification of single bacteria within minutes.
Advanced Spectroscopy and Microscopy III
icon_mobile_dropdown
A pupil tracking system for adaptive optics retinal imaging
Betul Sahin, Fabrice Harms, Barbara Lamory, et al.
High-resolution imaging of the retina is a challenge due to the optical aberrations introduced by the eye, a living system in constant change and motion. Adaptive Optics (AO) is particularly suited to the continuous, dynamic correction of aberrations as they change over time. In particular, eye pupil displacements induce fast-changing wave front errors which lead to a need for faster wave front sensors. We propose a new approach for ocular adaptive optics by adding a Pupil Tracking System (PTS) into the AO loop. This system is different from the existing eye tracking devices by its speed, high precision in a short range and therefore its suitability for integration in an AO loop. Performance tests done using an artificial eye with a pupil diameter of 7 mm have shown promising results. These tests have demonstrated that the device achieves an accuracy of <15 μm in a ±2 mm range of eye movements with a standard deviation <10 μm, and requires less than 12 ms for each detection.
Speckle interferometric system to measure ocular microtremor
James P. Ryle, Mohammed Al-Kalbani, Niamh Collins, et al.
Ocular microtremor (OMT) is a biological high frequency (up to 150Hz) low amplitude (25-2500nm peak to peak) involuntary motion of the human eye. Clinical OMT investigations to date have used eye-contacting mechanical piezoelectric probes or piezoelectric strain gauges. Before contact can be made, the eye must first be anaesthetized. In some cases, this eyelid spasms occur making it impossible to measure OMT. Using the contact probe method, the eye motion is mechanically loaded. Results from clinical studies with this method to date have given electrical signal amplitudes from the probe proportional to the displacement, but not the exact displacement information. Recent studies suggest a number of clinical applications for OMT, these include monitoring the depth of anesthesia of a patient in surgery, prediction of outcome in coma, diagnosis of brain stem death. In addition to this, in patients with neurological disorders such as Multiple Sclerosis and Parkinson's disease, abnormal OMT frequency content is present. In this paper, we design a compact non-contact phase modulating optical fiber speckle interferometer to measure eye motions. We simulate OMT motion using a calibrated piezoelectric vibration simulator and compare results produced using a contact method with those using our optical non-contact method.
Optical Coherence Tomography
icon_mobile_dropdown
Combining confocal microscopy and optical coherence tomography for imaging in developmental biology
A. Bradu, Lisha Ma, J. Bloor, et al.
In-vivo Optical Coherence Tomography (OCT) imaging of the fruit fly Drosophila melanogaster larval heart allows non invasive visualizations and assesment of its cardiac functions. To image Drosophila melanogaster heart, we have developed a dedicated imaging instrument able to provide simultaneous Optical Coherence Tomography (OCT) and Laser Confocal Scanning Microscopy (LCSM) or Laser Scanning Fluorescence Microscopy (LSFM) images and can be used to produce B-scan OCT images. With this dual imaging system, the image of heart can be easily located in the specimen and the change of the heart shape in a cardiac cycle monitored. This technique therefore provides an excellent tool for large scale screen of candidate genes responsible for the contractility of the Drosophila heart. As this technique can also image the dynamic process of the heartbeat in a non-invasive fashion, it provides a new avenue to study the physiology of the heart function. En-face and B-scan OCT images of the Drosophila melanogaster heart showing its chambers have been obtained with our imaging instruments. Our results are consistent with detailed anatomical studies from the literature.
An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses
Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.
Optical Fibers, Assays, and Sensors I
icon_mobile_dropdown
A novel nano-photonics biosensor concept for rapid molecular diagnostics
Dion J. W. Klunder, Maarten M. J. W. van Herpen, Aleksey Kolesnychenko, et al.
We present a novel nano-photonics biosensor concept that offers an ultra-high surface specificity and excellent suppression of background signals due to the sample fluid on top of the biosensor. In our contribution, we will briefly discuss the operation principle and fabrication of the biosensor, followed by a more detailed discussion on the experimentally determined performance parameters. Recent results on detection of fluorescently labeled molecules in a highly fluorescent background will be shown, and we will give an outlook on real-time detection of bio-molecules such as proteins and nucleic acids.
Self-calibrated dynamical optical biochip system using surface plasmon resonance imaging: application to genotyping
Jérôme Hottin, Julien Moreau, Jolanda Spadavecchia, et al.
The present paper summarizes some of our work in the field of genetic diagnosis using Surface Plasmon Resonance Imaging. The optical setup and its capability are presented, as well as the gold surface functionalization used. Results obtained with oligonucleotides targets, specific to Cystic Fibrosis disease, in high and low concentration are shown. The self-calibration method we have developed to reduce data dispersion in genetic diagnosis applications is described.
Development of cell-based quantitative evaluation method for cell cycle-arrest type cancer drugs for apoptosis by high precision surface plasmon resonance sensor
Toshihiro Ona, Hiroshi Nishijima, Atsushi Kosaihira, et al.
In vitro rapid and quantitative cell-based assay is demanded to verify the efficacy prediction of cancer drugs since a cancer patient may have unconventional aspects of tumor development. Here, we show the rapid and non-label quantitative verifying method and instrumentation of apoptosis for cell cycle-arrest type cancer drugs (Roscovitine and D-allose) by reaction analysis of living liver cancer cells cultured on a sensor chip with a newly developed high precision (50 ndeg s-1 average fluctuation) surface plasmon resonance (SPR) sensor. The time-course cell reaction as the SPR angle change rate for 10 min from 30 min cell culture with a drug was significantly related to cell viability. By the simultaneous detection of differential SPR angle change and fluorescence by specific probes using the new instrument, the SPR angle was related to the nano-order potential decrease in inner mitochondrial membrane potential. The results obtained are universally valid for the cell cycle-arrest type cancer drugs, which mediate apoptosis through different cell-signaling pathways, by a liver cancer cell line of Hep G2 (P<0.001). This system towards the application to evaluate personal therapeutic potentials of drugs using cancer cells from patients in clinical use.
Optical Fibers, Assays, and Sensors II
icon_mobile_dropdown
New optical analyzer for 13C-breath test
Hermann Harde, Matthias Dressler, Günther Helmrich, et al.
Medical breath tests are well established diagnostic tools, predominantly for gastroenterological inspections, but also for many other examinations. Since the composition and concentration of exhaled volatile gases reflect the physical condition of a patient, a breath analysis allows one to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that is based on photoacoustic spectroscopy and uses a DFB diode laser at 2.744 μm. The concentration ratio of the CO2 isotopologues is determined by measuring the absorption on a 13CO2 line in comparison to a 12CO2 line. In the specially selected spectral range the lines have similar strengths, although the concentrations differ by a factor of 90. Therefore, the signals are well comparable. Due to an excellent signal-noise-ratio isotope variations of less than 1% can be resolved as required for the breath test.
Quality limiting factors of imaging endoscopes based on optical fiber bundles
Nowadays, imaging endoscopes have a key role in medicine, for diagnostic, treatment and surgical applications. Coherent optical fiber bundles used for medical imaging show flexibility and a high active area, but they entail two main quality-limiting factors: leaky modes and crosstalk or interference between the optical fibers of the bundle. The former provokes a worsening of lateral resolution, while the latter causes a decrease in the contrast of the final image. In this work, both factors are studied in detail. We analyse the main characteristics of these effects, showing the limitations they impose to the endoscopic system. Finally, some solutions are proposed, and a method for determining optical fibers with the appropriate opto-geometrical parameters is presented in order to achieve an optimum design and improve the image quality of the endoscope.
Fluorescence and absorbance measurements for chromatographic analysis using a miniaturized micro-optical detection unit
Sara Van Overmeire, Heidi Ottevaere, Gert Desmet, et al.
We present a micro-optical detection unit for both laser induced fluorescence and absorbance analysis in fused silica capillaries, which can be used for chromatographic applications. The detection system is designed by means of non-sequential ray tracing simulations and prototyped by means of Deep Proton Writing. Such a prototyped master component is afterwards replicated by means of elastomeric moulding and vacuum casting. In a proof-of-concept demonstration the prototyped master micro-optical unit is used for the detection of various concentrations of coumarin dyes. The detection limit (SNR=3.3) achieved measures 0.6nM for fluorescence analysis and 12μM for absorbance measurements in capillaries with an inner diameter of 150μm. We discuss the optimization of different measurement parameters of the detectors in the setup in order to achieve accurate, fast and sensitive measurements.
Advanced Spectroscopy and Microscopy IV
icon_mobile_dropdown
How to measure slow diffusion in yeast cell membranes
Jonas Ries, Christian Klose, Christiane Walch-Solimena, et al.
Here we present two complementary methods for accurate diffusion measurements in yeast cell membranes. Fluorescence spreading after photobleaching analyzes the blurring of an initially sharp border between bleached and unbleached parts of the membrane. Two-focus scanning fluorescence correlation spectroscopy requires only a low concentration of labeled fluorophores and allows for very long measurement times due to correction for instabilities necessary to probe the slow diffusion in yeast plasma membranes. We apply these techniques to study the dynamics of different transmembrane proteins in the plasma membrane of the yeast Saccharomyces cerevisiae. The differences in the diffusion coefficients support the idea of co-existing membrane microdomains in the yeast plasma membrane.
Confocal light scattering and absorption spectroscopic microscopy
Le Qiu, Edward Vitkin, Saira Salahuddin, et al.
We have developed a novel optical method for observing submicron intracellular structures in living cells which is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light scattering spectroscopy (LSS). CLASS microscopy requires no exogenous labels and is capable of imaging and continuously monitoring individual viable cells, enabling the observation of cell and organelle functioning at scales on the order of 100 nm. In addition, it provides not only size information but also information about the biochemical and physical properties of the cell.
Advanced Spectroscopy and Microscopy V
icon_mobile_dropdown
Determination of the integral refractive index of cells in suspension by digital holographic phase contrast microscopy
Sebastian Kosmeier, Björn Kemper, Patrik Langehanenberg, et al.
A digital holographic microscopy method for the determination of the integral refractive index of living cells in suspension is presented. Therefore, digital holographic phase contrast images of trypsinized cells in suspension are recorded. Afterwards, the cell radius and the integral cellular refractive index are determined by fitting of a two dimensional model. The applied algorithm requires only information about the refractive index of the suspension medium and the scale of the microscopic imaging system. The fitting algorithm is characterized on simulated phase data and digital holographic phase contrast images of beads. Results obtained from living human pancreas tumor cells demonstrate the applicability of the method for cell characterization.
Non-invasive dry mass determination and monitoring at the single cell level with digital holographic microscopy
Benjamin Rappaz, Elena Cano, Jonas Kühn, et al.
Digital holography microscopy (DHM) is an optical microscopy technique which allows recording non-invasively the phase shift induced by living cells with nanometric sensitivity. Here, we exploit the phase signal as an indicator of dry mass (related to the protein concentration). This parameter allows monitoring the protein production rate and its evolution during the cell cycle.
Biological samples observed with diffractive tomographic microscopy
B. Simon, M. Debailleul, V. Georges, et al.
Many biological researches require observation of the sample at a sub-micrometer scale. However, most biological samples are transparent, and thus are barely visible in conventional transmission microscopy. Techniques like interference contrast or oblique illumination permit to record an improved contrast, but are useful for morphological studies only, because the interaction of incoherent, non-polarized and polychromatic illumination with matter is very complex, so that the recorded contrast cannot be linked to local physical properties of the sample, as for example the index of refraction. We have developed a diffractive tomographic microscope, which permits the observation of unstained-, transparent samples in 3-D. This device is based on a combination of microholography, which records the field diffracted by the specimen in both amplitude and phase using a high numerical aperture objective and a phase stepping interferometer, with a variable illumination of the sample (tomography) using a high numerical aperture condenser. The successive holograms are numerically recombined in the Fourier space, and the reconstruction of the specimen index of refraction distribution is based on the first Born approximation for weakly diffractive samples. Examples of biological specimens observed with this technique are given, and possible evolutions of the instrument are discussed.
Dynamically monitoring the gene expression of dual fluorophore in the cell cycle with quantitative spectrum analysis
Ja-Yun Lee, Tzong-Yuan Wu, I-Jen Hsu
The cloning and transcription techniques on gene cloned fluorescent proteins have been widely used in many applications. They have been used as reporters of some conditions in a series of reactions. However, it is usually difficult to monitor the specific target with the exactly number of proteins during the process in turbid media, especially at micrometer scales. We successfully revealed an alternative way to monitor the cell cycle behavior and quantitatively analyzed the target cells with green and red fluorescent proteins (GFP and RFP) during different phases of the cell cycle by quantitatively analyzing its behavior and also monitoring its spatial distribution.
Contrast mechanisms and signal epidetection in THG microscopy of scattering tissues
We use a vector field model to analyze the third-harmonic generation (THG) emission patterns for isolated objects illuminated by a Gaussian beam. Simulations and experiments indicate that THG from biological (dielectric) structures is essentially forward-directed, as opposed to e.g. THG from gold particles. We then address the issue of epidetecting forward-emitted light backscattered in a turbid medium. We use Monte Carlo simulations and measurements to analyze the effect of tissue properties (absorption, scattering), and of the geometry of the collecting optics. This analysis provides guidelines for optimizing epidetection in coherent nonlinear microscopy. An erratum is attached.
Photonic Therapies
icon_mobile_dropdown
Predictive analysis of photodynamic therapy applied to esophagus cancer
F. Fanjul-Vélez, M. del Campo-Gutiérrez, N. Ortega-Quijano, et al.
The use of optical techniques in medicine has revolutionized in many cases the medical praxis, providing new tools for practitioners or improving the existing ones in the fight against diseases. The application of this technology comprises mainly two branches, characterization and treatment of biological tissues. Photodynamic Therapy (PDT) provides a solution for malignant tissue destruction, by means of the inoculation of a photosensitizer and irradiation by an optical source. The key factor of the procedure is the localization of the damage to avoid collateral harmful effects. The volume of tissue destroyed depends on the type of photosensitizer inoculated, both on its reactive characteristics and its distribution inside the tissue, and also on the specific properties of the optical source, that is, the optical power, wavelength and exposition time. In this work, a model for PDT based on the one-dimensional diffusion equation, extensible to 3D, to estimate the optical distribution in tissue, and on photosensitizer parameters to take into account the photobleaching effect is proposed. The application to esophagus cancer allows the selection of the right optical source parameters, like irradiance, wavelength or exposition time, in order to predict the area of tissue destruction.
Optical Doppler tomography for monitoring vascularization during photodynamic therapy of skin cancer lesions
J. Thomsen, N. Bendsøe, K. Svanberg M.D., et al.
We investigate vascular changes during Photodynamic therapy (PDT) of skin tumors using optical Doppler tomography (ODT). The effect of vascular shut down on tumor destruction is currently not known, and to optimize treatment it is relevant to investigate this issue further. Optical Doppler tomography is capable of measuring blood flow in biological tissue down to 1-2 mm with sub-mm/s velocity sensitivity and micrometer spatial resolution making it suitable for blood flow measurements in the skin. We demonstrate the ability of detecting blood flow in the human skin using non-interstitial ODT to preserve the non-invasiveness. In general a very limited blood flow activity was observed in normal skin and around skin tumors making monitoring of changes difficult. We suggest solutions to a number of practical issues such as sampling errors and natural fluctuations in flow activity for future work.
Potential of systemic photosensitizers for PDT of skin malignancies
Carsten M. Philipp, Ute Müller, Peter Urban, et al.
Usually systemic photosensitizers (PS) require a long period of incubation (48-96h) after systemic admission. On the other hand clearing from healthy skin needs weeks or months. Severe side effects on skin are possible in case of uncontrolled light exposure. Topical PDT may solve this problem, but deep portions may not be sufficiently sensitized, resulting in a survival of some tumor cell population after PDT and recurrence. The same problem counts for actinic keratosis and Bowen's disease, but with even worse consequences as a resulting infiltrating growing squamous cell carcinoma (SCC) is likely to produce metastatic lesions. Light dosimetry is crucial also. Wavelenght, fluence and total energy may influence outcome of any PDT substantially. 17 patients with Bowen's disease or BCC where treated using a novel systemic PS (Fotolon®) and 665nm light from a diode laser. Follow up time ranges between 2.5 and 1 years after treatment. 2 patients received a second PDT, in 15 patients one treatment was efficient. We found a remissions in 1, local control in 2 and no evidence of disease in 14 patients. Significant fluorescence was noted in all lesions. With a light protection protocol for only 48 hours no severe side effects where seen. One patient developed mild redness of sunlight exposed skin sites 24h after being discharged from light protection protocol. In comparison with currently available topical PS Fotolon® offers some important advantages as secure photosenzitation of deep portions, single treatment, high selectivity combined with a high cure rate. In comparison with currently available systemic PS Fotolon® offers short incubation time, high selectivity and short time of elimination, while efficiency was comparable to HPD (hematoporphyrin-derivate) PDT combined with ALA-5 PDT and without need for additional local PS-application for PDD.
Improved tumour response by laser light treatment
Georgi Graschew, Janice Smith, Stefan Rakowsky, et al.
Multidrug resistance (MDR) poses a serious barrier to the efficacy of clinical treatment of human cancers with chemotherapeutic drugs. This barrier might be reduced and eventually overcome by the simultaneous application of two or more treatment modalities. This study reports on the synergetic effect of combined application of laser light and cytostatic drugs to induce an improved tumour response in MDR cancer cells. The MDR breast cancer cell line MaTu/ADR, resistant to the drug adriamycin (ADR), was treated with a combination of ADR (125-1000 ng/ml) and laser light (488 nm with a total light dose between 6-18 J/cm2). This combined treatment leads to an additional reduction of the cell vitality by a factor of 2-3 as compared to treatment with ADR alone, suggesting that combined application of laser light and other treatment modalities might constitute a promising strategy for improvements in the tumour response.
Poster Session
icon_mobile_dropdown
Improved design of a laser scanning system for food analysis applications
W. Meulebroeck, P. Berghmans, H. Thienpont
Scanning systems are used in many applications where on-line, high-speed analysis of products is needed. Because of the growing demand for healthy and high quality food products, these systems found their way in several food sensing applications. We will focus on an optical scanning system used for the identification and quality control of vegetables and fruits. It should be able to detect defects as small as 1.5 millimeter and should have a uniform sorting contrast over the entire length of the scanning line. Depending on the application, the analysis process is based on different interaction phenomena such as selective absorption or fluorescence. In this work we first analyzed which parts of the scanning system influence the size of the smallest detectable defect and how the system should be designed in order to fulfill a predefined size. This was done by experimentally analyzing a standard optical scanning system. The major part of our work concentrates on the uniformity of the sorting contrast which depends on the amount of light captured by the detector. We learned that for the standard scanning system this contrast strongly depends on the position of the product in the scanning line. In this paper we highlight the factors which are responsible for this effect and describe a new system characterized by a uniform sorting contrast. The simulations related to this last part were performed with the aid of the optical analysis software ASAP.
Quasi-simultaneous OCT/confocal imaging
A new approach of acquiring quasi-simultaneous OCT and confocal images is presented. The two images are generated using different principles, optical coherence tomography (OCT) and confocal microscopy (CM). When the system is used to image the retina, the two images have depth resolutions, at present, of less than 20 μm and approximately 1 mm respectively. The acquisition and display of en-face OCT and confocal images are quasi-simultaneous, without the need of a beam splitter. By using a chopper to periodically obstruct the reference beam in the OCT interferometer, synchronized with the XY-transversal scanner, much higher acquisition speed is obtained than in a previous report where we flipped an opaque screen in the reference arm of the interferometer. Successful operation of the novel configuration was achieved by: (1) stable synchronization of the chopper's movement with the horizontal line scanner and (2) fast self-adjusting of the gain value of avalanche photodiodes depending on the optical power. Images from coin, leafs and retina in vivo have been collected to demonstrate the functionality of the system.
Pneumatic skin flattening (PSF): a new technology for more selective, safer and painless coupling of an intense treatment laser beam into the skin
Michael Slatkine, Eric F. Bernstein, Gary Lask, et al.
Pneumatic skin flattening (PSF) is a new technology which enables painless and safer coupling of an intense treatment laser beam into the skin with enhanced spectral selectivity. Applications are mainly in aesthetic laser and IPL treatments. PSF generates vacuum over the skin, followed by very fast suction and flattening of the skin against a Sapphire window. The utilization of a translucent diffusing Sapphire window considerably enhances safety without compromising efficacy. PSF clinical advantages are: - Pain inhibition which is attributed to the "gate theory of pain transmission" whereby strong enough "squeezing" of pressure receptors over a large area of the skin blocks the transmission of pain to the brain in the dorsal horn. - Expulsion of blood from the treatment beam pathway. This results in a more transparent skin. - Reduced post treatment erythema and edema. - Increased distance between target and underlying structures. - Capability to increase efficacy by the increase of energy without pain. Controlled clinical studies of pain reduction and efficacy over ~100 patients have been conducted in X6 clinical centers. The studies confirmed the clinical advantages of PSF with high statistical significance and repeatability. The adaptability of PSF technology to almost any laser or IPL enables the entire worldwide aesthetic laser/IPLs install base to take advantage of this new technology.
Biophotonic applications of optical communication devices
Recent advances in technology have spawned a rapidly growing use of photonic systems for life sciences related clinical and research applications. Many of these biomedical applications are using selections of passive and active optical components that were developed for optical fiber communication systems over the past two decades. This paper describes how the unique physical characteristics and light-transmission properties of various passive optical components developed for telecommunications address some of the basic challenges of photonic applications in the life sciences.
Personal UV biodosimeter for healthy indoor tanning
The practice of indoor tanning has led to the development of a large artificial tanning industry. In addition to psychological benefits, exposure to UVB light helps the body produce the activated form of vitamin D, which is necessary for many cellular functions. But uncontrolled tanning and UV overexposure can increase the risk of skin cancer. For direct checkout of the vitamin D synthetic capacity of a UV source the bio-equivalent UV dosimeter has been developed that is based on the same molecular photochemistry from which vitamin D is photosynthesized in human skin and makes possible both instrumental and visual indication of vitamin D synthesis.
Mid-infrared pulsed laser lithotripsy using an Er:YAG laser and a difference frequency generation laser
Hisanao Hazama, Shinya Yamada, Katsunori Ishii, et al.
We conducted fundamental research on a novel lithotripsy technique using mid-infrared pulsed lasers. We irradiated gallstones extracted from the common bile duct using two mid-infrared lasers, namely, a difference-frequency generation (DFG) laser tunable within a wavelength range of 5.5-10 μm and an Er:YAG laser with a 2.94 μm wavelength, and then examined the depth and dimension of the crater formed. Some of the gallstones were continuously wet with distilled water during laser irradiation. The absorption spectrum of the gallstones was measured using a Fourier transform infrared spectrometer. The gallstones showed a strong peak around the wavelengths of 2.94 and 6.83 μm. In the case of DFG laser irradiation, the wavelength used was 6.83 μm and the average power density range of the laser was about 2-52 W/cm2. After irradiation, a relatively small hole with a depth range of 0.1-0.2 mm and a dimension within 0.01-0.04 mm2 was created. On the other hand, in the case of Er:YAG laser irradiation, the average power density range was about 0.20-0.78 kW/cm2. As the result, a large hole was made and the mass of 0.4-1.6 mg was removed. In conclusion, wet gallstones were more decomposed than dry gallstones in both cases of laser irradiation, and these techniques proved to be effective for gallstone lithotripsy.
Implant bone interface investigated with a non-invasive method: optical coherence tomography
Bone implants insertion implies the necessity of a important primary stability. The quality of the implant insertion could be investigated by implant bone interface analysis. In this study, we demonstrate that en-face optical coherence tomography can be used to evaluate these interfaces. We have collected both C-scan OCT images (en-face) as well as B-scan OCT images (cross section). 3D analysis was possible by acquiring 30-100 C-scans which were used post-acquisition to explore the volume of the tissue around the interface. Four implants were inserted into a human mandible and their interfaces imaged. The images show gaps of different sizes and shapes between the implant and the bone at different depths.
Investigation of bracket bonding for orthodontic treatments using en-face optical coherence tomography
Despite good diagnosis and treatment planning, orthodontic treatment can fail if bonding fails. It is now common practice to address the aesthetic appearance of patients using aesthetic brackets instead of metal ones. Therefore, bonding aesthetic brackets has become an issue for orthodontists today. Orthodontic bonding is mainly achieved using composite resin but can also be performed with glass ionomer or resin cements. For improving the quality of bonding, the enamel is acid etched for 30 seconds with 38% phosphoric acid and then a bonding agent is applied. In our study we investigated and compared the quality of bonding between ceramic brackets, polymeric brackets and enamel, respectively using a new investigation method-OCT. The aim of our study was to evaluate the resin layer at the bracket base-tooth interface.
Quantitative estimates of vascularity in a collagen-based cell scaffold containing basic fibroblast growth factor by non-invasive near-infrared spectroscopy for regenerative medicine
Toshihiro Kushibiki, Kunio Awazu
Successful tissue regeneration required both cells with high proliferative and differentiation potential and an environment permissive for regeneration. These conditions can be achieved by providing cell scaffolds and growth factors that induce angiogenesis and cell proliferation. Angiogenenis within cell scaffolds is typically determined by histological examination with immunohistochemical markers for endothelium. Unfortunately, this approach requires removal of tissue and the scaffold. In this study, we examined the hemoglobin content of implanted collagen-based cell scaffolds containing basic fibroblast growth factor (bFGF) in vivo by non-invasive near infrared spectroscopy (NIRS). We also compared the hemoglobin levels measured by NIRS to the hemoglobin content measured with a conventional biological assay. Non-invasive NIRS recordings were performed with a custom-built near-infrared spectrometer using light guide-coupled reflectance measurements. NIRS recordings revealed that absorbance increased after implantation of collagen scaffolds containing bFGF. This result correlated (R2=0.93) with our subsequent conventional hemoglobin assay. The NIRS technique provides a non-invasive method for measuring the degree of vascularization in cell scaffolds. This technique may be advantageous for monitoring angiogenesis within different cell scaffolds, a prerequisite for effective tissue regeneration.
Root canal filling evaluation using optical coherence tomography
The root canal fillings are destined to seal the root canal especially in the apical areea. Invasive techniques are known which are used to assess the quality of the seal. These lead to the destruction of the probes and often no conclusion could be drawn in respect to the existence of any microleakage in the investigated areas of interest. Optical coherence tomography (OCT) is a relatively novel non-invasive imaging technique which presents potential in assessing the microleakage of the apical area in the root canal fillings with micron depth resolution. 3D reconstruction allows a complete view with obvious display of gaps in the apical root canal filling. For this study, 30 monoradicular teeth were prepared by conventional and rotative methods. Afterwards, root canal fillings were produced in each tooth. The images obtained show some microleakage in all the investigated root canal fillings. The advantages of the OCT method consist in non-invasiveness and high resolution.
Fibres reinforced dentures investigated with en-face optical coherence tomography
The complete dentures are currently made using different technologies. In order to avoid deficiencies of the prostheses made using the classical technique, several alternative procedures have been devised. In order to enhance the mechanical strength, complete denture bases are reinforced with fibres. Their material and structure vary wildly, which makes the investigation difficult. In this study, optical coherence tomography (OCT) is evaluated as a possible non-invasive technique to assess the biomechanical behaviour of the reinforcing fibres. OCT images demonstrate structural defects between fibres and the acrylic material in all dentures bases investigated. We conclude that OCT can successfully be used as a noninvasive analysis method.
Vanishing tattoo multi-sensor for biomedical diagnostics
E. Moczko, I. Meglinski, S. Piletsky
Currently, precise non-invasive diagnostics systems for the real-time multi detection and monitoring of physiological parameters and chemical analytes in the human body are urgently required by clinicians, physiologists and bio-medical researchers. We have developed a novel cost effective smart 'vanishing tattoo' (similar to temporary child's tattoos) consisting of environmental-sensitive dyes. Painlessly impregnated into the skin the smart tattoo is capable of generating optical/fluorescence changes (absorbance, transmission, reflectance, emission and/or luminescence within UV, VIS or NIR regions) in response to physical or chemical changes. These changes allow the identification of colour pattern changes similar to bar-code scanning. Such a system allows an easy, cheap and robust comprehensive detection of various parameters and analytes in a small volume of sample (e.g. variations in pH, temperature, ionic strength, solvent polarity, presence of redox species, surfactants, oxygen). These smart tattoos have possible applications in monitoring the progress of disease and transcutaneous drug delivery. The potential of this highly innovative diagnostic tool is wide and diverse and can impact on routine clinical diagnostics, general therapeutic management, skin care and cosmetic products testing as well as fundamental physiological investigations.
Optical characterization of porous silicon microcavities for glucose oxidase biosensing
G. Palestino, V. Agarwal, D. B. Garcia, et al.
PSi microcavity (PSiMc) is characterized by a narrow resonance peak in the optical spectrum that is very sensitive to small changes in the refractive index. We report that the resonant optical cavities of PSi structures can be used to enhance the detection of labeled fluorescent biomolecules. Various PSi configurations were tested in order to compare the optical response of the PSi devices to the capture of organic molecules. Morphological and topographical analyses were performed on PSiMc using Atomic Force (AFM) and Scanning Electron (SEM) microscopies. The heterogeneity in pores lengths resulting from etching process assures a better penetration of larger molecules into the pores and sensor sensitivity depends on the pore size. Molecular detection is monitored by the successive red shifts in the reflectance spectra after the stabilization of PSiMc with 3-aminopropyltriethoxysilane (APTES). The glucose oxidase was cross linked into the PSiMc structures following a silane-glutaraldehyde (GTA) chemistry.
Novel useful sun strategy to improve physical endurance
R. N. Khramov, L. I. Fakhranurova, I. M. Santalova, et al.
We propose a "useful sun" strategy with application of a photoluminophore that absorbs a part of the UV component of the sunlight and converts it into the visible light. As a result, the "harmful" UV sun radiation becomes useful. The present study was designed to determine the effect of additional luminescent radiation with λm=626nm on the physical endurance in 12-week-old male mice. Four groups of animals were used: Control I, intact animals; Control II, exposure to standard artificial day light 5 BT/M2; Control III, exposure to solar radiation with absorbed UV-component; and Experiment, exposure to converted solar radiation with an additional orange-red luminescent component in the range of 603-637 nm (0.11 J/cm2 per day). The experimental group showed a significant increase (by more than 50%) in swimming time to exhaustion as compared to Control III. No significant difference in physical endurance was found between Control III and Control II. These results suggest that improvement in swimming endurance by the solar light is due to an additional orange-red luminescent component in the range of 603-637 nm.
Optical detection of PNA/DNA hybridization in resonant porous silicon-based devices
Lucia Rotiroti, Paolo Arcari, Annalisa Lamberti, et al.
The development of label-free optical biosensors could have a great impact on life sciences as well as on screening techniques for medical and environmental applications. Peptide nucleic acid (PNA) is a nucleic acid analog in which the sugar phosphate backbone of natural nucleic acid has been replaced by a synthetic peptide backbone, resulting in an achiral and uncharged mimic. Due to the uncharged nature of PNA, PNA-DNA duplexes show a better thermal stability respect the DNA-DNA equivalents. In this work, we used an optical biosensor, based on the porous silicon (PSi) nanotechnology, to detect PNA-DNA interactions. PSi optical sensors are based on changes of reflectivity spectrum when they are exposed to the target analytes. The porous silicon surface was chemically modified to covalently link the PNA which acts as a very specific probe for its ligand (cDNA).
Specific peptide for functionalization of GaN
E. Estephan, C. Larroque, T. Cloitre, et al.
Nanobiotechnology aims to exploit biomolecular recognition and self-assembly capabilities for integrating advanced materials into medicine and biology. However frequent problems are encountered at the interface of substrate-biological molecule, as the direct physical adsorption of biological molecules is dependent of unpredictable non-specific interactions with the surface, often causing their denaturation. Therefore, a proper functionalization of the substrate should avoid a loss of biological activity. In this work we address the functionalization of the semiconductor GaN (0001) for biosensing applications. The basic interest of using III-V class semiconductors is their good light emitting properties and a fair chemical stability that allows various applications of these materials. The technology chosen to elaborate GaN-specific peptides is the combinatorial phage-display method, a biological screening procedure based on affinity selection. An M13 bacteriophage library has been used to screen 1010 different peptides against the GaN (0001) surface to finally isolate one specific peptide. The preferential attachment of the biotinylated selected peptide onto the GaN (0001), in close proximity to a surface of different chemical and structural composition has been demonstrated by fluorescence microscopy. Further physicochemical studies have been initiated to evaluate the semiconductor-peptide interface and understand the details in the specific recognition of peptides for semiconductor substrates. Fourier Transform Infrared spectroscopy in Attenuated Total Reflection mode (FTIR-ATR) has been employed to prove the presence of peptides on the surface. Our Atomic Force Microscopy (AFM) studies on the morphology of the GaN surface after functionalization revealed a total surface coverage by a very thin, homogeneous peptide layer. Due to its good biocompatibility, functionalized GaN devices might evolve in a new class of implantable biosensors for medical applications.
Development of a new autofluorescence probe for the analysis of normal and tumour brain tissues
R. Siebert, M. H. Vu Thi, F. Jean, et al.
Fluorescence spectroscopy of endogenous emission of brain tumors, in particular glioblastoma multiforme, will be used for intraoperative localization of brain tumor margins. Our future surgeon's probe aims to discriminate tumor from normal brain tissues using beta and autofluorescence detection at the same time. Within this study we have implemented C6 glioma cells into rat brains to analyze the endogenous fluorescence of tumor and normal rat brain tissue. Systematic differences have been observed when comparing the autofluorescence spectra obtained from white and grey matters: both the fluorescence intensity and the shape of the spectra differ. These results were obtained by means of a 2-fiber probe, one used to guide the laser to the tissue, the other for fluorescence light collection. Excitation light was delivered by a 405 nm picosecond laser and fluorescence detection was realized by a CCD-camera. In parallel we have developed brain phantoms allowing systematic analysis of fiber - sample geometries. Based on gelatin gels, they include silica particles with 235 and 329 nm diameters to simulate the diffusion characteristics of the tissue, ink for the absorption characteristics of the tissue and organic dyes like Rhodamin B to replace biofluorophores.
Waveguide-excited fluorescence microarray
Gabriel Sagarzazu, Mélanie Bedu, Lucio Martinelli, et al.
Signal-to-noise ratio is a crucial issue in microarray fluorescence read-out. Several strategies are proposed for its improvement. First, light collection in conventional microarrays scanners is quite limited. It was recently shown that almost full collection can be achieved in an integrated lens-free biosensor, with labelled species hybridizing practically on the surface of a sensitive silicon detector [L. Martinelli et al. Appl. Phys. Lett. 91, 083901 (2007)]. However, even with such an improvement, the ultimate goal of real-time measurements during hybridization is challenging: the detector is dazzled by the large fluorescence of labelled species in the solution. In the present paper we show that this unwanted signal can effectively be reduced if the excitation light is confined in a waveguide. Moreover, the concentration of excitation light in a waveguide results in a huge signal gain. In our experiment we realized a structure consisting of a high index sol-gel waveguide deposited on a low-index substrate. The fluorescent molecules deposited on the surface of the waveguide were excited by the evanescent part of a wave travelling in the guide. The comparison with free-space excitation schemes confirms a huge gain (by several orders of magnitude) in favour of waveguide-based excitation. An optical guide deposited onto an integrated biosensor thus combines both advantages of ideal light collection and enhanced surface localized excitation without compromising the imaging properties. Modelling predicts a negligible penalty from spatial cross-talk in practical applications. We believe that such a system would bring microarrays to hitherto unattained sensitivities.
Positive changes in the myocardium of SHR rats induced by photon radiation
I. M. Santalova, N. M. Zakharova, R. N. Khramov, et al.
Hypertensive SHR male rats were irradiated by a photon light-emitting diode matrix with a maximum irradiation at 612 nm with dose 1.44 J/cm2 per day . After a course of irradiation (13 days) the rhythmoinothropic characteristics of cardiac muscle significantly improved. Morphological analysis shown considerable changes in the structure of sarcoplasmic reticulum (SR), i.e. area of SR profiles increased more than twofold compared to control. This suggests a proportional increase in ability of SR to absorb calcium, due to both an increase in its buffer capacity and possibly, an improved functioning of Ca2+ ATPase of the reticulum. This could lead to an improvement in calcium homeostasis in the myocytes, and explain the improvement of the characteristics of cardiac muscle contraction-relaxation cycle. Furthermore, changes were observed in proportions of the myocardium capillaries (increased by 75%; compared to control, p<0.001) and in the area of mitochondrial profiles of the myocytes (increased by 13%, p<0.05). This lead to of more active metabolic processes and an energy rise occurring in myocardial cells after photon radiation treatment.
Comparative analysis of tissue structure via Mueller matrix characterization of liquid crystals
Polarization properties of light interacting with biological tissues change depending mainly on tissue structure. In this work, a comparative method for the extraction of information about tissue structure is proposed, based on the analysis of polarization properties of liquid crystals. The Mueller matrix of the tissue is decomposed by means of the Lu-Chipman polar decomposition. As long as the scattering is weak, and so depolarization is sufficiently low, the tissue structure can be considered similar to the one of the equivalent liquid crystal. This model is applied to a sample of healthy porcine skin measured in backscattering configuration.
Comparative study of primary and secondary tumors from patients with laryngeal and oropharyngeal cancer, using transmission electron microscopy
Ligia Gabriela Ghetea, Ana-Maria Niculescu, Rozalia Magda Motoc, et al.
In modern laboratories, the study of cancer is performed using a series of cellular and molecular methods based on optical instruments measurements. Optical and electron microscopy are valuable tools for revealing morphological features of cancer cells. Our study was focused on laryngeal and oropharyngeal cancers, which have nowadays an increased incidence, especially for women, due to unhealthy habits like tobacco and alcohol consumption. We used transmission electron microscopy (TEM) for highlighting the ultrastructural features of cancer cells, both in primary and secondary tumors. The primary tumor is considered that which appears for the first time, at a certain organ; the secondary tumor is that which reappears at the same region or neighbouring regions, at a certain interval of time after the primary one has been surgically removed. The differences between the inner architecture of the cells from primary and secondary tumors where correlated with the expression of some genes (oncogenes and tumor suppressor factors), in order to establish the aggressiveness of the tumor, in different disease stages. The main stress in the study is placed upon electron microscopy, in order to achieve a more precise characterization of both these type of cancer cells. These ultrastructural data complete the image of laryngeal and pharyngeal cancer cells, along with molecular data obtained by Real-Time PCR.
Genetic characterization of some Romanian red wine grapevine varieties
Ligia Gabriela Ghetea, Rozalia Magda Motoc, Ana-Maria Niculescu, et al.
In our study we have considered three of the most valuable Romanian red wine grapevine cultivars: Feteasca neagra, Feteasca alba and Novac. We have chosen to study grapevine because grapes and wine are an important part of a healthy diet, and because red grapes have the highest content of proanthocyanidins, that act as antioxidants (free radical scavengers) in the human body. Proanthocyanidins possess anti-mutagenic, anti-tumor, anti-viral activities and they present many other confirmed or potential benefits. Genotyping method was applied in order to asses the genetic profile at 14 microsatellite loci, for two cultivars: Feteasca neagra and Feteasca alba. In order to achieve this, the HPLC-DAD method was used. The content of anthocyans in grape skin from two cultivars - Feteasca neagra and Novac - was measured. Microsatellite markers have been certified as powerful tools for assessing genetic identities and genetic relationships between grapevine gene pools. Genetic characterization of grapevine cultivars can certify their authenticity and purity, two features that have a direct effect on the quality and value of the finished product, the wine. In our country, this is the first attempt in order to establish a genetic profile for valuable Romanian origin grapevine varieties. In some of the 14 microsatellitic loci, Feteasca neagra and Feteasca alba cultivars presented allele size variants different from the values cited in the literature, proving that these cultivars belong to a geographical distinct gene pool. The content of anthocyans in Feteasca neagra grape skin was significantly higher than in Novac.
Combined Monte Carlo and finite-difference time-domain modeling for biophotonic analysis
Yasser R. Hijazi, Cemre Kortun, Dizem Arifler
Monte Carlo (MC) modeling is widely used to study photon transport in tissues but is generally performed using simplified phase functions that only approximate the angular scattering probability distribution of microscopic tissue constituents such as cells. Finite-Difference Time-Domain (FDTD) modeling has recently provided a flexible approach to compute scattering phase functions for realistic cell geometries. We present a computational framework that combines MC and FDTD modeling and allows random sampling of scattering directions from cellular phase functions computed using the FDTD method. Combined MC/FDTD simulation results indicate that the exact form of the phase function used is an important factor in determining the modeled optical response of tissues. Subtle differences in angular scattering probability distribution can lead to significant changes in detected reflectance intensity and the extent of these changes depends on the specific range of scattering angles to which a given optical sensor design is most sensitive.
Design of specific biochips for contrast enhancement of UV biological absorption
Kristelle Robin, Jean-Luc Reverchon, Laurent Mugherli, et al.
This paper describes the design of biochips enhancing absorption in UV (and more particularly at 260-280 nm). These contrast-enhancing multilayers structures are developed in order to image biological compounds immobilized at a surface. The measurement set-up is a reflection set-up, including a previously developed AlGaN detector, spectrally selective at the wavelength of biological compounds absorption (260 nm for DNA and 280 nm for proteins). A contrast study is carried out using an inorganic absorber (titanium dioxide), enabling an optimized electromagnetic interaction with the absorber. The biochip design is based on an aluminum mirror covered with a transparent dielectric. To account for roughness and oxidation, the material is modeled by a thin layer of effective medium defined in the Bruggeman approximation. We discuss the absorption expected from various biological compounds, and the capability of our set-up for detection of monolayers of DNA or protein molecules.
Photobiomodulation of early mouse embryo development
T. A. Sviridova-Chailakhyan, L. I. Fakhranurova, N. B. Simonova, et al.
The effect of artificial sunlight (AS) from a xenon source and of converted AS with an additional orange-red luminescent (λMAX=626 nm) component (AS+L) on the development of mouse zygotes was investigated. A plastic screen with a photoluminophore layer was used for production of this orange-red luminescent (L) component. A single short-term (15 min) exposure produced a long-term stable positive effect on early embryo development of mice, which persisted during several days. After exposure to AS+L, a stimulating influence on preimplantation development was observed, in comparison with the control group without AS exposure. The positive effects were as follows: increase in percent of embryos (P ≤ 0.05) developed to the blastocyst stage (96.2 %) with hatching from the zona pellucida (80.8 %) within 82-96 hours in vitro compared to the control (67.1 % and 28.8 %, respectively).
Modeling of epithelia transport phenomena related with the acetowhitening optical changes: potential for the in vivo diagnosis of cervical neoplasia
George Papoutsoglou, Antonis Potirakis, Costas Balas
A molecular imaging method employing acetic acid dilute solution as a biomarker of cervical neoplasia is described and the interpretation of the biophysical processes involved determining the in-vivo measured dynamic scattering characteristics is presented. A compartmental model of the epithelium has been developed for predicting the epithelial transport phenomena that are expected to be correlated with the dynamic characteristics of the backscattered light. Model predictions have been compared and confirmed by experimental data obtained from patients with cervical neoplasia of different grade, with the aid of specially developed imaging system. Results revealed that the dynamic scattering characteristics and both structural and functional alterations are largely determined by the intracellular proton concentration kinetics. This highlights the potential of the developed imaging method and technology for the non-invasive diagnosis, guided therapeutics and screening of cervical neoplasia.
FDTD simulation of optical phase contrast microscope imaging
Stoyan Tanev, James Pond, Paul Paddon, et al.
The Finite-Difference Time-Domain (FDTD) approach is applied to model optical phase contrast microscope (OPCM) imaging of Gold nanoparticles (NPs) in singe biological cells. We first demonstrate the effect of optical clearing on the optical phase contrast microscope image of a realistic size biological cell containing a cytoplasm, a nucleus and a membrane. The FDTD-based OPCM model is then applied to visualize the presence of a cluster of Gold NPs in the cytoplasm at optical conditions. To the best of our knowledge, this is the first study using the FDTD approach in combination with Fourier optics techniques to construct OPCM images of realistic size cells containing NPs. The results demonstrate the potential of the FDTD modelling approach and extend its area of applicability into a new biomedical research area.
Synthesis and characterization of monodisperse Eu-doped luminescent silica nanospheres for biological applications
Francesco Enrichi, Raffaele Riccò, Alvise Parma, et al.
Luminescent nanoparticles are gaining more and more interest for bio-sensing and bio-imaging applications. In particular it is desiderable to work with cheap and non toxic materials which could be easily functionalized in their surface. To these respects silica nanoparticles seem to be a very promising and interesting solution. The liquid synthesis of silica spheres can be obtained by condensation of tetraethylortosilicate (TEOS) in basic or acid environment. Several strategies have been developed to make them luminescent by the incorporation of organic or inorganic emission centres, but often requiring multiple processing steps and use of expensive or toxic molecules. Moreover, common dyes suffer disadvantages such as a broad spectral band, short fluorescent lifetime and photobleaching. In contrast, rare earths exhibit narrow emission bands, large Stokes shifts and long luminescence lifetimes. In this work we focus our attention on the synthesis and characterization of europium-doped silica spheres. Europium introduction in the spheres can be interesting for biological applications to increase the signal to noise ratio due to the long luminescence lifetime (possibility to perform time-delayed analysis) and to the good emission intensity. The obtained results are presented and discussed, giving suggestions for the optimization of their morphological and optical properties. The possibility of realizing good luminescent silica spheres by following the described procedure is shown and suggestions for future development are given. The cheap and easy synthesis of these luminescent particles, the stability in water, the easy surface functionalization and bio-compatibility makes them very attractive in biological imaging and other applications.
Optical properties of tissues after laser treatments in the wavelength range of 350 - 1000 nm
Katsunori Ishii, Akinori Kimura, Kunio Awazu
In laser medicine, the accurate knowledge about the optical properties of target tissue is important for the understanding prediction of propagation and distribution of light in tissues. Light propagations, absorption and scattering, changes by the kinetic changes of optical properties in laser irradiations. This problem is clinically very important for the realization of safe laser treatments because the understandings of optical properties by several laser parameters can realize the pre-estimated treatment effects. The objective of this study is determination of the optical properties of treated tissues for the safe laser treatments. In this paper, we examined to determine the optical properties changes of a coagulated tissue after the Er:YAG laser irradiations by using double integrating sphere system and inverse adding-doubling method in the wavelength range of 350 - 1000 nm. After laser irradiations with a variety of irradiation parameters, the absorption coefficient of a treated tissue decreased and the reduced scattering coefficient of a treated tissue increase. In carbonization, observed in 30 sec-300 mJ irradiation, the absorption coefficient of a treated tissue re-increased and the reduced scattering coefficient of a treated tissue re-decrease. The changes of optical properties should be accounted for while planning the therapeutic procedure for the realization of safe laser treatments.
Imaging and interferometric analysis of protein crystal growth
Ranjini Raghunandan, Anamika Sethia Gupta, K. Muralidhar
Protein crystals are grown under controlled temperature, concentration and vapor pressure conditions, usually by vapor diffusion, liquid-liquid diffusion and dialysis techniques. The present study examines the effects of protein concentration, drop size and reservoir height on the crystal growth of Hen Egg White Lysozyme (HEWL). Crystals are grown by the hanging drop vapor diffusion method using Modular VDXTM Plates. Due to the vapor pressure difference created between the protein drop and the reservoir, evaporation takes place till equilibrium is attained. Crystal formation takes place after a certain level of supersaturation is attained when the protein precipitates out in crystalline form. The observations revealed that the growth is faster for higher lysozyme concentration, smaller drop sizes and larger reservoir heights. The morphology of the crystals is viewed during the growth process using stereomicroscope. The number of crystals formed is the maximum for higher concentrations, drop sizes and reservoir heights. When the number of crystals formed is less, the size of the crystals is comparatively larger. The effect of evaporation of water vapor from the protein drop into the reservoir is studied using Mach-Zehnder interferometry. The recorded interferograms and shadowgraph images indicate the diffusion of condensed water into the reservoir. The radius of the drop is determined using the shadowgraph images of the growth process. The radius decreases with evaporation and the rate of decrease of radius is highest for higher protein concentrations, smaller drop sizes and larger reservoir heights.
Methods to increase efficiency of laser therapy of oncologic diseases: methods, equipment, experiment
The rapid development of quantum electronics and the advent of various types of lasers favored the formation of an independent line in medicine, namely, laser medicine In recent years devices based on semiconductor lasers have been introduced into medicine at a most rapid pace At present day this is connected with , that the essential improvement energy and spectral features has occurred in development semiconductor laser. The power of serial discrete near-IR semiconductor lasers has reached a level of 5 W and more, the spectral range has extended to 1.7...1.8 μm. Laser-optical information technologies and devices develop since the 70- years at the end of 20 century and are broadly used for treatment of oncologic diseases. Although such methods as photodynamic therapy (PDT), laser-induce thermotherapy (LITT), fluorescent diagnostics and spectrophotometry already more than 30 years are used for treatment and diagnostics of oncologic diseases, nevertheless, they are enough new methods and, as a rule, are used in large scientific centers and medical institutions. This is bound, first of all, with lack of information on modern method of cancer treatment, the absence of widely available laser procedures and corresponding devices in the polyclinics and even in district hospitals, as well as insufficient understanding of application areas, where laser methods has an advantage by comparison, for instance, with beam or chemotherapy. Presented in the article are new developed methods and results of designing equipment and software for their realization aimed at increase in efficiency of treatment of oncologic diseases as well as several clinical materials of the use of industrial models of the developed devices at medical institutions.
The modern trends of the evolution laser information technology in oncology
Laser-optical information technologies and devices develop since the 70- years at the end of 20 century and are broadly used for diagnostics and treatment of oncological diseases to date. Although such methods as photodynamic therapy (PDT), laser-induce thermotherapy (LITT), fluorescent diagnostics and spectrophotometry already more than 30 years are used for treatment and diagnostics of oncological diseases, nevertheless, they are enough new methods and, as a rule, are used in large scientific centers and medical institutions. This is bound, first of all, with lack of information on modern method of cancer treatment, the absence of widely available laser procedures and corresponding devices in the polyclinics and even in district hospitals, as well as insufficient understanding of application areas, where laser methods has an advantage by comparison, for instance, with beam or chemotherapy. At present day laser methods are fast upcoming direction of the treatment oncological diseases. This is explained by progress in development essentially laser, particularly diode, improvement electronic and computing components and broad introduction software-algorithmic methods of control the undertaking therapeutic and diagnostic procedures. In article are considered new laser methods of the undertaking diagnostic and therapeutic procedures and is shown that introduction multiwave laser radiation for probe and influences on tissue, the different methods of the determination of the functional state of tissues, realization of the on-line diagnostics when carrying out the therapeutic procedures, automatic control systems of the power laser radiation, which depends on state patient tissue, as well as software-algorithmic methods of management session therapeutic and diagnostic procedures greatly raises efficiency of the treatment oncological diseases. On an example of the multipurpose laser therapeutic devices("MLTA") developed and introduced in clinical practice and multipurpose laser diagnostic complexes ("MLDC"), the realizing offered methods, are shown the basic tendencies of development laser methods in oncology, concrete technical decisions and the experimental clinical material showing increase of efficiency of treatment of a cancer at their realization are resulted. It is shown, that realization of the offered methods and technical technologies opens new competitive advantages laser technologies in comparison with beam and chemical-therapy at treatment of oncological diseases.
Irradiation by pulsed Nd:YAG laser induces the production of extracellular matrix molecules by cells of the connective tissues: a tool for tissue repair
Monica Monici, Venere Basile, Francesca Cialdai, et al.
Many studies demonstrated that mechanical stress is a key factor for tissue homeostasis, while unloading induce loss of mass and impairment of function. Because of their physiological function, muscle, connective tissue, bone and cartilage dynamically interact with mechanical and gravitational stress, modifying their properties through the continuous modification of their composition. Indeed, it is known that mechanical stress increases the production of extracellular matrix (ECM) components by cells, but the mechanotransduction mechanisms and the optimal loading conditions required for an optimal tissue homeostasis are still unknown. Considering the importance of cell activation and ECM production in tissue regeneration, a proper use of mechanical stimulation could be a powerful tool in tissue repair and tissue engineering. Studies exploring advanced modalities for supplying mechanical stimuli are needed to increase our knowledge on mechanobiology and to develop effective clinical applications. Here we describe the effect of photomechanical stress, supplied by a pulsed Nd:YAG laser on ECM production by cells of connective tissues. Cell morphology, production of ECM molecules (collagens, fibronectin, mucopolysaccharides), cell adhesion and cell energy metabolism have been studied by using immunofluorescence and autofluorescence microscopy. The results show that photomechanical stress induces cytoskeleton remodelling, redistribution of membrane integrins, increase in production of ECM molecules. These results could be of consequence for developing clinical protocols for the treatment of connective tissue dideases by pulsed Nd:YAG laser.
New technology of cerebral oxygenation measurements by time-resolved spectroscopy
Near-infrared spectroscopy has been widely used to determine the oxygenation of cerebral tissue. New technology of cerebral oxygenation measurements based on time resolved registration of backscattered radiation of probing picosecond laser pulse are considered.
Wearable wireless photoplethysmography sensors
Janis Spigulis, Renars Erts, Vladimirs Nikiforovs, et al.
Wearable health monitoring sensors may support early detection of abnormal conditions and prevention of their consequences. Recent designs of three wireless photoplethysmography monitoring devices embedded in hat, glove and sock, and connected to PC or mobile phone by means of the Bluetooth technology, are described. First results of distant monitoring of heart rate and pulse wave transit time using the newly developed devices are presented.