Simple preparation of an Au nanoparticle dispersed substrate by arc plasma deposition and its application in bio-sensing using LSPR.

We propose a simple preparation of a Localized Surface Plasmon Resonance (LSPR) device in which Au nanoparticles (AuNPs) are dispersed on SiO₂/Si substrates using arc plasma deposition (APD). APD can coat AuNPs directly onto a substrate using a single-step process with a very short deposition time. The dispersion and diameter of the AuNPs were evaluated based on the APD characteristics: applied voltage (V), capacitance (C), and number of pulses (n). The LSPR device was prepared under the best conditions for reflectance spectra: C = 2200 μF, V = 100 V, n = 80, and a vacuum of 1.3 × 10^-3 Pa at room temperature, and protein-protein interactions (PPIs) were detected using the device. The fabricated device could detect avidin over a wide range from 1 ng mL^-1 to 10 μg mL^-1. The detection limit was 0.33 ng mL^-1, which is considerably low compared to that of other detection methods. These results demonstrate that APD is useful for fabricating superior nanoparticles without additional processes such as photolithography and etching.