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Development of Three New Optical Bio-sensing Instruments: Circular Polarization Interferometry, Miniature Handheld Surface Plasmon Resonance Biosensor and Radially Polarized Surface Plasmon Microscope
Chih-Kung Lee, Chih-Hsiang Sung, Chia-Ming Jan, Ching-Sung Chen, Dominique Chauvat, and Joseph Zyss

In this article, we introduce three new optical bio-sensing instruments developed by our research team. The first instrument is a multi-functional biochip system called “OBMorph”, which is composed of an ellipsometric SPR with circular polarization interferometry which can be used to retrieve sensitive optical response on a surface. The OBMorph system enables us to control the incident angles easily with the paraboloidal mirrors to allow phase interrogation. Previous studies have shown that ellipsometric parameters can provide high resolutions up to 1 ng/ml for closed-channel IgG and Anti-IgG reaction measurements. Recently, we advanced the concept of an ITO-based chip by modifying the intrinsic ITO optical property by adopting an externally applied voltage which shifts the SPR angle for the required dynamic range by phase-interrogation. The refractive index of the ITO was analyzed for a change level at 10-4 while the externally applied DC voltage was set at under 100 mV. The second instrument we developed was a miniature handheld SPR device which has characteristics such as easy alignment, high sensitivity and low power consumption. Its advantages enable it to be used as a practical point-of-care-test (POCT) tool. The third instrument we developed was a dual-channel radially polarized surface plasmon microscope (SPM) system which offers high sensitivity for single nanoparticle detecting measurements. The complementary fluorescent image and the back-scattered image from the nanoparticle were found to be well co-localized.

Keywords: Surface plasmon resonance, ellipsometry, interferometry, circular polarization, radial polarization, surface plasmon microscope, point-of-care, handheld

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