LSPR Sensor Chip Fabricated Based on Au Nanoparticles: Effect of Graphene Oxide and Reduced Graphene Oxide
Abstract Nanoparticles of noble metals are well known to display unique optical properties due to the localized surface plasmon resonance (LSPR) phenomenon, making them applicable for use as transducers in various LSPR sensor configurations. In order to develop a sensor chip, Au nanoparticles (AuNPs) were decorated onto a transparent glass substrate in the form of a uniform, high-density single layer using a self-assembly monolayer (SAM) process. The glass substrate surface was initially modified with amine functional groups using different concentrations of (3-Aminopropyl) triethoxysilane (APTES), followed by its optimization to reach a uniform monolayer of AuNPs. The optimized substrate was subsequently prepared by functionalization with APTES, while also being immersed into colloidal AuNPs. A uniform layer of Graphene oxide (GO) and reduced graphene oxide (rGO) sheets were coated on the AuNPs thin films using the dip-coating technique. The AuNPs/GO and rGO hybrid films were employed along with an appropriate optical set up acting as a smart sensor chip for detection of different concentrations of biomaterials. The optimum LSPR sensor (%0.5 APTES immersed in colloidal AuNPs for 12 h) resulted in a chip with %29 absorption and sharper plasmon peak. This appropriate condition remained constant after adding rGO, indicating that Glass/AuNPs/rGO chip will be suitable for sensory applications.
