This PDF file contains the front matter associated with SPIE Proceedings Volume 11256, including the title page, copyright information, table of contents, and author and conference committee lists.

Plasmonic nanoparticles such as gold, silver or their alloys are interesting nanomaterials for their applications in therapeutics and diagnostics in nanomedicine. In this presentation, I will present recent developments performed in this field at Polytechnique. A new method for delivering exogenous biomolecules into targeted cells using an ultrafast laser and plasmonic nanoparticles will be presented. The technique of plasmon-mediated laser nanosurgery has been used to effectively perform gene transfection in various living cells and delivery of biomolecules in vivo in animal model for ophthalmic applications. This technology has been also used for locally stimulating neurons to control neuronal activity and cell signaling. Moreover, alloy nanoparticles have been synthesized using an improved seeded-growth approach. These spectrally distinctive plasmonic nanoparticles are used as biomarkers to perform quantitative multiplexed 3D imaging of cells and tissues. Our techniques show promises of innovative tools for basic research in biology and medicine as well as effective alternative technologies that could be adapted to the therapeutic, diagnostic, theranostics tools of the clinic.

Measurements and imaging of the electric and magnetic fields inside living cells are important for understanding many biophysical interactions. In particular, membrane potential plays a critical role in cellular communication processes, regulation of active transport and generation of action potential. While most of the active research is focused on developing fluorescent labels for detecting and quantifying membrane potential, the use of endogenous markers for the electric field potential measurements would allow extended measurements of the electric field potential, which could be important both for fundamental research and clinical studies. In this report, the vibrational Stark spectroscopy is evaluated. It is demonstrated that it has sufficient sensitivity to assess physiologically significant variations of the membrane potential.

Shortwave infrared quantum dots (QDs) are promising probes for in vivo imaging in depth. Here, we present two strategies to design pH-sensitive ratiometric QD in vivo probes. In the first one, central fluorescent QDs are coated with a copolymer ligand and conjugated to gold nanoparticle (AuNP) quenchers. As the pH decreases from physiological (7.5) to slightly acidic (5.5−6), the copolymer reversibly shrinks, which modulates the QD fluorescence signal through energy transfer. In a second design, QDs and AuNPs are encapsulated into micelles using pH-sensitive copolymer surfactants, providing stability in serum, sharp pH transitions and high contrast.

This study details a polydopamine-coated gold nanorod synthesis for photoacoustic imaging. The most important finding is that the photoacoustic intensity and spectrum shifted upon coating with polydopamine. We used this photoacoustic signal change to identify samples in a phantom. Additionally, the polydopamine-coated gold nanorods exhibited an increase in stability over bare nanorods under photoacoustic irradiation. Future studies will study drug release and will monitor from the polydopamine coating and monitor the fate of the gold nanorods over time in vivo.

For the first time, we assess the biodistribution and toxicity of unshelled CIS and partially zinc-alloyed CISZ QDs in a murine model at 1-day, 7-day, and 1-month timepoints. We show that bare CIS QDs breakdown quickly, with >75% of the initial dose being cleared by 1-month. Surprisingly, we also demonstrate a significant toxic response to these QDs as measured by organ weight, blood chemistry, and histology. Specifically, low doses of CIS particles (15mg/kg) induce severe hepatotoxicity and splenotoxicity. Similarly, CISZ demonstrated significant, but lower, toxicity compared to bare CIS. Overall, our data suggests that reconsideration of CIS as a translatable QD system is required: degradation-based toxicity is an important aspect of biocompatibility that needs to be assessed in “non-toxic” QDs, if QDs are to ever be clinically successful. Finally, we suggest a non-toxic biodegradable alternative.

Many new applications are being developed using silica nanoparticles for bioanalytical, biomedical or forensic applications where both surface and bulk properties of silica nanoparticles control the analytical process. Surface modified silica nanoparticles that are copolymerized with one or more types of small organic molecules, including fluorescent dyes can be synthesized relatively easily using a wide range of organic molecules, due to the wide availability of modified reactive TEOS analogues. These silica nanoparticles that are copolymerized with dye molecules can be utilized as bright fluorescence labels, sensors or for molecular recognition. In addition, covalently surface bonded moieties can be added to silica nanoparticles to modulate the surface behavior of the silica nanoparticles.

A biomimetic photoacoustic nano-probe is synthesized for enhanced the diagnostic accuracy of hepatocellular carcinoma. It is prepared by using erythrocyte membrane to coat the gold nano-star which shows significant photothermal effect. This probe can escape the clearance by mononuclear phagocytic system because of the inherent proteins on the surface of the erythrocyte membrane. Such an ability to evade immune clearance allows a longer circulation time in vivo, promotes probe enrichment at tumor site, and improves signal-to-noise ratio. Sequentially, it is used as an agent of non-invasive photothermal treatment for tumor and experimentally perform a longer life span of mice.

Innovations in novel probes have significantly push the development of new optical spectroscopy and microscopy methods for revealing new information in biological systems. In this talk, I will discuss our recent development by introducing chemical probes to stimulated Raman scattering (SRS) microscopy that could allow multi-functional imaging at sub-cellular level. Both physical and chemical principles underlying the investigation and design of new probes when coupled to the Raman imaging modalities will be presented, as well as our efforts in biomedical applications including cancer- and neuronal- metabolism

There is an unmet need for simple-to-use oximetry devices that can map tissue oxygenation over large areas while being easily integrated into clinical standard-of-care workflows. We present a phosphorescence-based approach which features red-emitting porphyrin molecule constructs, embedded within a paint-on hydrogel bandage for tissue oxygen concentration imaging. The bandage emission is visible by eye which enables oxygen imaging even in the presence of skin autofluorescence. Preclinical testing to validate correlations between bandage oxygenation maps and perfusion is ongoing, and by allowing gelation to occur on the skin the bandage can conform to odd topologies, such as ears.

Single molecule localization microscopy (SMLM) relies on the detection of fluorescence emission from a single fluorophore molecule. Recently, several fluorescent dyes with spontaneous blinking have been reported. Last year, we reported a near-infrared dye with spontaneous blinking and high photostability. Here, we present a new orangefluorescent dye that exhibits spontaneous blinking based on equilibrium between the fluorescent and non-fluorescent forms. We have also ascertained that the new dye can be used to create a super-resolution image of cytoskeletal microtubules. In combination with our near-infrared dye reported last year, the new dye is expected to allow dual-color SMLM.

Dimethyl-2,5-bis(4-methoxyphenylamino)terephthalate (1) exhibits very feeble emission in acetone solution, but is strongly emissive in the solid state. In order to develop an understanding of the processes responsible for such behavior, fluorescence studies have been performed on solutions of 1 in acetone-water mixtures. Increase in water content of these solutions is found to result in broadening of the absorption spectra along with red shift of the absorption maximum, suggesting the formation of aggregates. The process of aggregation is associated with a significant enhancement of the emission intensity. This is a manifestation of the aggregation induced enhanced emission (AIEE) phenomenon. Quantum chemical calculations reveal a propeller-like shape of the molecule, which is an essential criterion for AIEE-active molecules. The major nonradiative relaxation of the excited state of this molecule is likely to involve the rotation of the molecular segments with respect to each other. X-ray diffraction studies reveal a stacking pattern, which is likely to hinder such nonradiative decativation of the excited state, leading to the enhanced emission in solid state and aggregated state of the molecule. The trend of variation of emission intensity, as a function of water content of the mixture, is in line with the size of aggregates formed in these mixtures, as is brought out by light scattering studies. Electron microscopy reveals that the microstructure of the aggregates as well as the solid powder of 1 consists of nanorods. Fluorescence lifetimes indicate that the nature of the emissive species in the aggregates and the solid is the same. Thus, a systematic understanding of the structure and photoprocesses in the aggregates is developed.

A new approach to assess popularity relies on analysis of the number of times a web article is viewed. Here, a strategy is described to identify chemicals of widespread interest. The strategy makes use of Wikipedia, a rapidly growing publicly editable web encyclopedia that has become an influential knowledge base. While the total number of chemicals mentioned in Wikipedia is unknown, use of the Wikipedia Chemical Structure Explorer (WCSE) developed by Novartis enables identification of those that are described in an Infobox or Chembox along with a Simplified Molecular-Input Line-Entry system (SMILES) code. Using a Python script, all so-listed chemicals (16,243) in Wikipedia were identified and then sorted on the basis of their pageview rankings. Of the 16,243 chemicals, 846 (5.2%) belonged to controlled substances (United States Drug Enforcement Administration), WHO essential medicines, or the top 300 US drugs. These 846 chemicals received 220 million pageviews, which is 41.4% of the pageviews for all members of the Wikipedia chemical list. The number of chemicals described in the entire corpus of Wikipedia remains a tiny fraction of the <10⁷ known chemicals. Much remains to be done to make the venerable literature and data of chemistry readily accessible. Regardless, identification of popular chemicals in this manner can be used to create selected databases, to tailor educational curricula, or to create targeted informational materials (such as safety brochures); such considerations of public demand are likely to engender corresponding widespread interest.

Absorption and fluorescence spectra are foundational data for studies in photochemistry as well as any area of science or technology that entails electronic spectroscopy. The data of interest include the spectra (graphs of intensity as a function of wavelength or wavenumber), the respective quantitative photophysical parameters – molar absorption coefficient [ε(λ)] and the fluorescence quantum yield [Φ_f] – and the conditions under which the data were obtained. Yet such qualitative and quantitative data are scattered across a wide landscape. Modern search engines provide access to much of the world’s published scientific literature (<10⁸ articles) spanning <100 years but are surprisingly ineffective at pinpointing spectra and companion photophysical parameters. Manual curation has led to valuable collections albeit of uneven contents: some include spectra, others include only listings of spectral data (e.g., positions of peak intensity [λ_max]), and many are not available in digital form. Numerous calculations in photophysics, such as propensity for Förster resonance energy transfer (FRET), require spectra and cannot be carried out with tabular listings of values of λ_max, ε(λ) and Φ_f. Here, we summarize the spectral data available in 27 printed archives (beginning in the early 20th century), in repositories or databases at a dozen dedicated websites, and via scholarly literature search tools. The websites and search tools include PubChem, ChemSpider, NIST Chemistry WebBook, SciFinder, Reaxys, Google Scholar, Microsoft Academic, and Web of Science. This work is part of a long-term project to organize and assemble the world of spectral data for the molecular photosciences.

This article discusses the effect of nanopore size on the emission properties of a porous carbon material with a density of 1.4 g/cm³. Atomistic models of porous carbon materials with different nanopore sizes have been constructed. Numerical experiments were carried out using the density functional method with allowance for periodic boundary conditions. It is established that the work function of a porous carbon material with a density of 1.4 g/cm³ decreases with an increase in the size of nanopores and an increase in the concentration of cesium ions.

The theoretical molecular-mechanical method using the AIREBO energy potential was modernized to study the mechanical properties of porous carbon nanostructures doped with potassium atoms. The selection of coefficients was carried out by solving a minimax problem based on experimental data of the distances between the potassium and carbon atoms. The choice of this particular method for modifying and studying the mechanical properties of nanostructures is due to the necessity of calculating a large number of atoms with minimal time expenditures and with no loss of calculation accuracy. The study of mechanical properties was carried out depending on the size of the nanopores of the porous carbon nanostructure. The modernization consisted in the selection of weighting coefficients to describe the interaction between potassium and carbon atoms. Physical interaction is described by the Lennard-Jones potential. This modernization was performed to study the mechanical properties of carbon nanostructures of doped potassium atoms.

In this study, we used GROMACS, a versatile package for performing molecular dynamics to simulate the interactions between different nanoparticles and Dipalmitoyl PhosPhatidyl Choline (DPPC) to understand the physical mechanisms that govern the interactions between nanoparticles and lipid membrane. Our simulations show the responses of the lipid bilayer to the nanoparticles, including the formation of an adsorbent layer on the nanoparticle surface, transmembrane ectopic movements and inconspicuous endocytosis of the nanoparticle by the membrane. Effects of the size of the nanoparticles, structural shape and charge state on the interaction and transport processes will be examined and summarized.

The research for the energy stability of columnar graphene was carried out. It has been established that pillared graphene with zigzag carbon nanotubes and mixed chirality of carbon nanotubes (zigzag and armchair) are energy-stable. An obligatory criterion of sorbent is energy stability. Therefore, pillared graphene with chirality of zigzag carbon nanotubes and mixed chirality of carbon nanotubes (zigzag and armchair) can be used as an element base of nanofilters for water desalination.

This work is devoted to solving the problem of reducing the work function of a pillared graphene structures. A computational experiment was performed. The purpose was to study various structures of pillared graphene, the cavities of which are filled with potassium. The stability of structures was estimated from the energy of formation, the work function – from the Fermi energy. It was found, that work function decreases with an increase of potassium mass fraction – decrease by 1 eV was reached at 10% mass fraction of potassium and decreasing by 2-2.6 eV has been established at the maximal mass fraction of potassium.

In this work, the sensory properties of a thin film of a Co₃O₄ monocrystal 0.5 nm in thick with a (111) plane are studied on the example of alcohol molecules of methanol, ethanol, propanol, and butanol. The regularities in the interaction of alcohol molecules with film surface are investigated. The energy profiles of interaction are calculated and the values of activation energy are determined. It is established that the value of activation energy is determined by the weight of the adsorbed molecule and its configuration relative to the surface of cobalt oxide. The regularity of the change in the electrical resistance of the Co₃O₄ film during the adsorption of various alcohol molecules was revealed. It is found that the monocrystalline nanostructure of cobalt oxide Co₃O₄ is very promising as a sensory surface, which makes it possible to register individual molecules.

In this work, we investigate in silico the patterns of the interaction of natural polymer matrices based on a network of single-walled carbon nanotubes (SWCNTs), albumin and collagen with the cell membrane. A layer of phospholipid molecules is considered as a cell membrane. The simulation is carried by means of the coarse-grained approach using the MARTINI force field. During the simulation of contact of the membrane with the matrix, the membrane moved to the matrix with an average blood flow velocity of 0.5 m/s, which simulates the collision of blood elements with the surface of the SWCNT-natural polymer matrix. It is established that during the interaction of natural polymer matrices with cell membranes, the matrices do no harm to the cell membrane.