Highly reproducible fiber optic surface plasmon resonance biosensors modified by CS2 for disposable immunoassays

To achieve fiber optic surface plasmon resonance (SPR) biosensors for disposable immunoassays, the following activities are required: first, to manufacture highly consistent fiber optic SPR sensors; second, to develop highly reproducible and reliable surface modification methods for the sensors; third, to establish methods of analysis and evaluation to determine the capability and reliability of biomolecular detection. In this work, we prepared microprobe-type fiber optic SPR sensors and selected highly consistent sensors according to the Pearson correlation coefficient (PCC) model. To obtain reliable surface modification, carbon disulfide (CS2) was introduced as a crosslinker to modify anti-human IgG on the surface of fiber optic SPR biosensors for the first time. After systematic improvement and optimization, the CS2-based biosensors obtained a higher human IgG sensitivity and lower human IgG detection limit than conventional (11-MUA)-based biosensors. The PCC model was employed to evaluate the consistency of the surface-functionalized biosensors, and experimental results showed that the CS2-based biosensors exhibited reliable consistency, while the (11-MUA)-based biosensors did not. Finally, the proposed CS2-based biosensors have high selectivity and work well in serum. The surface modification method and reliable and consistency evaluation model for the sensors reported in this paper can contribute to the development of disposable fiber optic SPR biosensors.