Polymer‐Based Prism‐Free Nanograting SPR Imaging Enables Multiplexed Detection and Single‐Step Aptamer Binding Kinetics

ABSTRACT Surface plasmon resonance (SPR) is a benchmark for label‐free biomolecular interaction analysis, but traditional prism‐based systems are costly, time‐consuming, and limited in multiplexing. We present a prism‐free, low‐cost, single‐use polymer‐based Au nanograting SPR imaging (SPRi) platform using normal‐incidence optics and camera‐based detection. Integrated with a microarray, the platform demonstrates multiplexed analysis capability. Furthermore, the incorporation of a custom microfluidic design enables simultaneous, multi‐concentration kinetic analysis in a single step. Demonstrated using thrombin–aptamer interactions with 1 s time resolution, the system yielded dissociation constants of 10.1 ± 0.05 n m (kinetic) and 8.71 ± 0.59 n m (steady‐state), consistent with literature values. This approach offers high‐throughput potential for aptamer screening, drug discovery, biomedical applications, and life science research.