Two-Dimensional Materials Enhanced Surface Plasmon Resonance for Antibiotic Sensing

Abstract

Two-dimensional (2D) materials attract attention by the academic community due to their excellent properties, and its wide application in sensing is expected to revolutionize environmental monitoring, medical diagnostics, and food safety. In this work, we systematically evaluate the effects of 2D materials on the Au chip surface plasmon resonance (SPR) sensor. Variations between the sensitivities under different modulation modes in regard to real part and imaginary part of refractive index (RI) and the thickness are simulated.  The 2D material's thickness needed for the highest sensitivity reduces with the increase of its real part and imaginary part of RI. Good agreements of the SPR enhancement are accomplished between the criteria-based predictions and the experimental verification of 5 nm-thickness MoS2 and single-layer graphene functionalized Au SPR chip. As a case study, we developed the 5 nm-thickness MoS2 enhanced SPR biosensor, which exhibited low sulfonamides (SAs) detection limit of 0.05 μg/L based on group-targeting indirect competitive immunoassay, nearly 12-fold lower than that of the bare Au SPR system. The proposed criteria help to shed light on 2D material-Au surface interaction, which has greatly promoted development of novel SPR biosensing with outstanding sensitivity.

Keywords: Two-dimensional materials, Surface plasmon resonance, Antibiotics, Sensitivity enhancement, Refractive index