Characterization of plasmonic effects in AuNP+rGO composite as a sensing layer for a low-cost lab-on-chip biosensor

• Main Author: Fantoni, Alessandro
• Publication Date: 2019
• Other Authors: Stojkovic, Vladan, Fernandes, Miguel, Louro, Paula, Vieira, Manuela, Alegria, Elisabete, Da Costa Ribeiro, Ana Paula, Carvalho, Ana, Almeida, M. Gabriela
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10400.21/11229
• topic: Biosensor; Localized Surface Plasmon Resonance (LSPR); Antibodies; Nanoparticles

This work deals with the production of a low-cost disposable biosensor for point of care applications. The proposed sensor is a plasmonic structure based on the Localized Surface Plasmon Resonance (LSPR) interaction of metal nanoparticles (MNPs), embedded into a matrix of reduced Graphene Oxide (rGO). After proper functionalization with selective antibodies (Ab), the efficiency of light extinction is controlled by slight changes of the refractive coefficient induced by the concentration of biomarkers trapped by the antibodies on the sensor surface. This work reports a study about the applicability of rGO as a support for gold nanoparticles (AuNPs) for preparing the functionalized LSPR sensing layer. AuNPs are prepared with an economic and eco-friendly method using phytochemicals present in tea extract at room temperature, while a modified Hummer’s method is used to synthesize rGO. The resulting AuNPs-rGO composites are studied in terms of UV-VIS spectroscopy spectral light transmission and plasmonic resonance. The overall analysis is supported by simulation results, obtained by Mie analysis, about the LSPR effect in AuNPs-rGO and its dependence on the biomarker concentration.