Comparison Between Two Polymer-Based Surface Plasmon Resonance Probes Combined with the Same Bioreceptor for Ochratoxin a Detection

In this work, a performance comparison between two Surface Plasmon Resonance (SPR) immunosensors for detecting ochratoxin A (OTA) in aqueous solutions is reported. More specifically, two SPR probes based on spoon-shaped waveguides and plastic optical fibers (POFs) were functionalized with the same anti-OTA receptor in order to assess and compare their biosensing performance. In both sensor configurations, the measurements pointed out a good linear relation among the variation in SPR wavelength values and the OTA concentration range from 0.2 ppt to 5 ppt, achieving binding sensitivities of about 1233 nm/ppb and 924 nm/ppb, and detection limits of 0.17 ppt and 0.18 ppt for the probe based on a spoon-shaped waveguide and POF, respectively. Each developed and tested polymer-based SPR biosensor presents an ultra-high sensitivity via a low-cost setup, representing an approach to realize portable analytical devices for on-site qualitative and quantitative OTA measurements in several application fields, like in coffee quality analyses.