Research PaperMiniaturized surface plasmon resonance biosensor with vacuum-driven hydrodynamic focusing

- A portable SPR biosensor integrated with microfluidics system was developed.
- Vacuum-driven microfluidics provide pulse-free and constant flow rate over a test period.
- Vertical focusing mechanism allows minimizing sample volume with the same sensitivity.
- The proposed system was fully verified with detecting streptavidin and prostate specific antigen (PSA).
- The vertical focusing mechanism is suitable for detecting low concentration biomarkers.

To apply surface plasmon resonance (SPR) biosensors into point-of-care testing (POCT), new techniques are required such as miniaturization, reduction of power consumption, and reduction of sample consumption. Although several miniaturized and portable SPR biosensors have been fabricated, they have not been developed for POCT because of the need for bulky liquid handlers, high power consumption, and large sample volumes. We developed a fully integrated portable SPR system with vacuum-driven vertical focusing microfluidics for POCT applications. The present SPR system was fully operated using a mobile PC battery by adopting an electric-power-free pump and an automated microfluidic system. Vertical focusing allowed the required sample volume to be significantly reduced (1/10 of that in conventional methods) without degrading sensitivity or measurement time. Additionally, the SPR system was found to be useful for detecting rare targets such as prostate specific antigen (PSA) in blood samples. We expect that the proposed system can be used in on-site monitoring systems in the fields of healthcare, food systems, and the environment.