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Proceedings Paper

Optical biosensor system with integrated microfluidic sample preparation and TIRF based detection
Author(s): Eduard Gilli; Sylvia R. Scheicher; Michael Suppan; Heinz Pichler; Markus Rumpler; Valentin Satzinger; Christian Palfinger; Frank Reil; Martin Hajnsek; Stefan Köstler
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Paper Abstract

There is a steadily growing demand for miniaturized bioanalytical devices allowing for on-site or point-of-care detection of biomolecules or pathogens in applications like diagnostics, food testing, or environmental monitoring. These, so called labs-on-a-chip or micro-total analysis systems (μ-TAS) should ideally enable convenient sample-in – result-out type operation. Therefore, the entire process from sample preparation, metering, reagent incubation, etc. to detection should be performed on a single disposable device (on-chip). In the early days such devices were mainly fabricated using glass or silicon substrates and adapting established fabrication technologies from the electronics and semiconductor industry. More recently, the development focuses on the use of thermoplastic polymers as they allow for low-cost high volume fabrication of disposables. One of the most promising materials for the development of plastic based lab-on-achip systems are cyclic olefin polymers and copolymers (COP/COC) due to their excellent optical properties (high transparency and low autofluorescence) and ease of processing. We present a bioanalytical system for whole blood samples comprising a disposable plastic chip based on TIRF (total internal reflection fluorescence) optical detection. The chips were fabricated by compression moulding of COP and microfluidic channels were structured by hot embossing. These microfluidic structures integrate several sample pretreatment steps. These are the separation of erythrocytes, metering of sample volume using passive valves, and reagent incubation for competitive bioassays. The surface of the following optical detection zone is functionalized with specific capture probes in an array format. The plastic chips comprise dedicated structures for simple and effective coupling of excitation light from low-cost laser diodes. This enables TIRF excitation of fluorescently labeled probes selectively bound to detection spots at the microchannel surface. The fluorescence of these detection arrays is imaged using a simple set-up based on a digital consumer camera. Image processing for spot detection and intensity calculation is accomplished using customized software. Using this combined TIRF excitation and imaging based detection approach allowes for effective suppression of background fluorescence from the sample, multiplexed detection in an array format, as well as internal calibration and background correction.

Paper Details

Date Published: 3 May 2013
PDF: 11 pages
Proc. SPIE 8774, Optical Sensors 2013, 87740C (3 May 2013); doi: 10.1117/12.2017436
Show Author Affiliations
Eduard Gilli, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Sylvia R. Scheicher, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Michael Suppan, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Heinz Pichler, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Markus Rumpler, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Valentin Satzinger, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Christian Palfinger, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Frank Reil, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Martin Hajnsek, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)
Stefan Köstler, JOANNEUM RESEARCH Forschungsgesellschaft mbH (Austria)

Published in SPIE Proceedings Vol. 8774:
Optical Sensors 2013
Francesco Baldini; Jiri Homola; Robert A. Lieberman, Editor(s)

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