The nature of PDMS affects the results of the immunoassays carried out in microfluidic channels

Due to various physical or biochemical processes, the nature of polydimethylsiloxane (PDMS) could affect the sensitivity and accuracy of immunoassays performed in microfluidic channels. An appropriate PDMS membrane with high adsorption properties and low background noise allows more sensitive detection of biomarkers. Here, we explored the unusual correlation between membrane surface properties and the signal-to-noise ratio (SNR) of immunoassay, developed a microfluidic-based versatile point-of-care (MVP) detection system on PDMS membrane to simultaneously detect multiple vitamins from multiple human serums. Compared with conventional enzyme-linked immunosorbent assay (ELISA) and Roche electroluminescence method, the MVP detection system exhibits a lower consumption of sample and reagents (10 µL per test), a lower limit of detection (LOD: 6.15 ng/mL), a higher SNR (33.49 dB) and multiplexed ability (seven samples and two targets in one assay). Our MVP detection system can quantitatively detect folic acid (FA) and vitamin D3 (VD3) from human serums and shows good consistency with ELISA and Roche electroluminescence methods. The R square values of FA and VD3 detections are 0.94 and 0.91, respectively. The MVP system is more cost-effective than utilizing conventional methods for a single detection (about 0.04 USD for each target) because of the straightforward design of our detection instruments, their superior anti-interference capabilities, and the low cost of routine instrument maintenance.