Tailor-made gold nanostar colorimetric detection determined by morphology change and used as an indirect approach by using hydrogen peroxide to determine glucose concentration

Abstract

Gold nanostars are being utilized more regularly in the field of nanodiagnostics. The modified seedless synthetic method comprised of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) synthesized with the addition of silver nitrate was applied for a biosensor application. The colorimetric ability of these newly synthesized nanostars showed to be more sensitive and more visually colorful than the HEPES gold nanostars synthesized without silver nitrate. It was observed that the gold nanostar colorimetric assay could be tailored for a specific application using either hydroxylamine or sodium hydroxide as colorimetric catalysts. Upon the attachment of glucose oxidase to the gold nanostars, glucose was measured by its oxidation and the generated hydrogen peroxide resulted in a sufficient color gradient that clearly distinguished different concentrations. Added to the color changes was the spectrophotometric localized surface plasmon resonance peak shifts in response to different glucose concentrations. In conclusion, the reported nanostars showed great potential as a good biosensing candidate