Wavelength-based localized surface plasmon resonance optical fiber biosensor

Two types of localized surface plasmon resonance (LSPR)-based optical fiber biosensors using gold nanospheres (GNSs) and gold nanorods (GNRs) have been developed and their performance characteristics evaluated and cross-compared successfully in this work. Based on the results obtained from the optimization of each of these types of biosensor and reported by the authors elsewhere, GNSs with a diameter of 60 nm and GNRs with an aspect ratio of 4.1 were specifically chosen in this work for the fabrication of two representative sensor probes, with an aim to create a highly sensitive and wavelength-based LSPR sensor to overcome the limitations arising from other intensity-based sensors. In order to develop effective LSPR biosensors, both GNSs and GRNs respectively were immobilized on an unclad surface of an optical fiber, prior to the functionalization with human IgG in order to create a device for the detection of anti-human IgG, at different concentrations. The experimental results obtained from tests carried out show that the sensitivities of GNSs and GNRs-based LSPR sensors to refractive index variation are 914 and 601 nm/RIU respectively; however as biosensors they have demonstrated the same detection limit of 1.6 nM for the detection of anti-human IgG.