A Low-Cost, Microvalve-Controlled Microfluidic Sensor for Surface Plasmon Resonance Detection

Surface plasmon resonance (SPR) is a highly sensitive, label-free optical detection technology widely used in biosensing applications. However, conventional SPR systems often face limitations in throughput and flexibility. To address these challenges, this study designed a multi-channel microfluidic-SPR sensing system with on-chip microvalves. The U-shaped microchannel structure can be completely sealed by pneumatic microvalves, and an additional wash channel effectively prevented dead volume. The microfluidic chip mold was manufactured using mechanical processing, resulting in a low production cost. It was combined with the SPR chip to form a universal, reusable, and fast sensing system through pressure sealing, allowing for simultaneous sample introduction and multi-target detection. Based on the principle of immunity, immunoglobulin G (IgG) and human serum albumin (HSA) were detected in different microfluidic channels, which proved that the presence of micro-valves in the microfluidic chip avoided cross-contamination of samples. This microfluidic-based SPR sensor reduced sample consumption, offering a solution for the development of portable, label-free, and instant biomedical diagnostic instruments.