Plastic extended optical-path-length absorbance Detection Microchip For On-Chip Prostate Specific antigen (PSA) quantification

This paper reports a new polymer extended optical-path-length absorbance-based detecting device for quantification of free PSA for point-of-care testing. The plastic COC device was fabricated using the polymer micromachining protocols, including multi-stage silicon molder, replica-molding and photolithographic protocols. The plastic-based microdevice incorporated with optical functions including micromirrors with minimum dead volume and a huge extended optical path length of 2 mm, which is the dimension in enzyme-linked immunosorbent assay (ELISA). We demonstrated the quantitative detection of free PSA, a prostate cancer biomarker, in range of 1~10 ng/ml on microchip with a 3 mul-volume chamber after positive and negative control tests.