- Immobilization of Surfactant Protected Gold Nano Cubes on the Glass Surface using Ligand Exchange for Sensing Applications
Immobilization of Surfactant Protected Gold Nano Cubes on the Glass Surface using Ligand Exchange for Sensing Applications
in: RSC Advances (2020)
In this report, we address an important issue associated with the utilization of excellent plasmonic properties of shape-anisotropic gold nanostructures for sensing application. Plasmonic nanoparticles having shapes of rods, triangles, cubes, stars, etc. are typically synthesized using surfactant assisted approaches. The utilized surfactants such as cetyltrimethylammonium bromide/chloride (CTAB/C) are afterwards still present on its surface and compromise the film formation ability on substrates such as glass surfaces. In this regard, we report a two step process for the ligand exchange as a combination of extraction and exchange reaction using poly(sodium 4-styrenesulfonate) (PSS) and trisodium citrate (TSC). CTAC stabilized gold nano cubes (CTAC/Au-NCs) synthesized using a microfluidic synthesis procedure were successfully deposited on silane modified glass substrate after ligand exchange from CTAC/Au-NCs to TSC stabilized gold nano cubes (TSC/Au-NCs). Further, TSC/Au-NCs were found to be highly stable and suitable for microfluidic sensing of different glucose concentrations using localized surface plasmon resonance (LSPR) spectroscopy offering a highly improved sensitivity (126.37 nm/RIU). The proposed method is also a promising tool for the immobilization of (CTAC/Au-NCs) protected other gold nanostructures such as rods, trangles, prism etc. on glass slide for optical sensing applications.