Innovation in SPR-Based Molecular Fishing: Development and Applications of an Indigenous Chinese Platform

Affinity capture is a key technique for isolating target molecules from complex biological samples. However, its efficiency is often constrained by methodological instability and procedural standardization, with accuracy and specificity serving as the core evaluation metrics. This study established a molecular fishing system based on the Chinese-developed and manufactured surface plasmon resonance (SPR) instrument MI-S200F, and systematically validated its performance across diverse biological samples. In the antigen-antibody fishing test, the MI-S200F exhibited markedly higher capture efficiency than the Biacore T200 SPR system and Octet R8 bio-layer interferometry (BLI) instruments, with a mass-recovery ratio of 25:3:1, demonstrating its superior target enrichment capability. For complex matrices such as 293F cell lysates and culture supernatants, MI-S200F selectively captured the target analyte with a purity of recovered material substantially higher than that achieved by BLI, effectively minimizing interference from non-specific adsorption. In the smallmolecule fishing validation, recovered analytes from MI-S200F and Biacore T200 were identified by LC–MS; both platforms accurately captured the target with identical fidelity. In summary, this study demonstrates that the Chinese-built MI-S200F SPR system exhibits high sensitivity and specificity in its molecular fishing module, highlighting its strategic value for promoting the broader adoption of Chinese-developed and manufactured high-end bioanalytical instrumentation.