Synthesis of Multi-Spike Gold Nanostar using the Surfactant-Free Method as LSPR Substrate Material

Gold nanostars (AuNNs) were synthesized by a surfactant-free wet-chemistry technique. The UV-Vis spectra and surface morphology showed the formation of AuNNs with average diameters of 20-30 nm and 100 nm, including those spikes. From the EDX and AFM analysis, the sample has high purity (above 79 wt%) and was successfully deposited on ITO glass with a 100-300 nm thickness. The current methods for synthesizing AuNNs often involve surfactants, which can interfere with their purity and application in sensitive optical sensors. There is a need for a reliable, surfactant-free synthesis method that produces high-purity AuNNs with consistent morphology, which can be effectively utilized in biosensing applications, particularly for detecting biomolecules such as creatinine. This study aims to synthesize AuNNs using a surfactant-free wet-chemistry method and to characterize their UV-Vis spectra, surface morphology, and purity. These findings are important for various optical sensor applications. As an initial measurement, AuNNs were promising to be used as an LSPR substrate material and applied to biosensors. Synthesized AuNNs and the initial optical performance using LSPR for creatinine detection are highlighted in this study.