Multiplexing of radiative-surface plasmon resonance for the detection of gastric cancer biomarkers in a single optical fiber

The simultaneous detection of multiple biological analytes is achieved for the first time using a single optical fiber based surface plasmon resonance (SPR) biosensor. This is achieved by collecting the plasmonic wave re-scattered by a rough metallic coating deposited onto two separate sections (sensing regions) of a single multimode optical fiber. The results obtained showed that two gastric cancer biomarkers (apolipoprotein E and clusterin) are detected in clinically relevant concentrations each on a separate sensing region, simultaneously, something that cannot be done in traditional fiber based SPR biosensors that read the transmitted or reflected light to monitor the position of the resonance. While this multiplexing demonstration has been performed with two different biomarkers, it paves the way for the multiplexed detection of a larger number of biomarkers using a simple fiber optic based SPR sensor for point of decision diagnostics.