Enhanced localized plasmonic detections using partially-embedded gold nanoparticles and ellipsometric measurements

Abstract

A cost-effective, stable and ultrasensitive localized surface plasmon resonance (LSPR) sensor based on gold nanoparticles (AuNPs) partially embedded in transparent substrate is presented. Partially embedded AuNPs were prepared by thermal annealing of gold thin films deposited on glass at a temperature close to the glass transition temperature of the substrate. Annealed samples were optically characterized by using spectroscopic ellipsometry and compare with theoretical modeling to understand the optical responses from the samples. By combining the partially-embedded AuNPs substrate with a microfluidic flow cell and dove prism in an ellipsometry setup, an ultrasensitive change in the LSPR signal can be detected. The refractive index sensitivity obtained from the phase measurement is up to 1938 degrees/RIU which is several times higher than that of synthesized colloidal gold nanoparticles. The sample is further used to investigate the interactions between primary and secondary antibodies. The bio-molecular detection limit of the LSPR signal is down to 20 pM. Our proposed sensor is label free, non-destructive, with high sensitivity, low cost, and easy to fabricate. These features make it feasible for commercialization in biomedical applications.

Gold nanoparticles assisted characterization of amine functionalized polystyrene multiwell plate and glass slide surfaces

“…4b. In the case of unmodified plate, AuNPs were not adsorbed on the surface (Moirangthem et al 2012;Carré and Lacarrière 2007;Fujiwara et al 2006). Figure 5a, b shows that the AuNPs stained modified and unmodified GS surface, respectively.…”

“…Covalent immobilization of biomolecules on PS and GS surfaces can be achieved using a variety of techniques including wet chemical treatments, silane monolayers, plasmas, flame, and UV irradiation (Goddard and Hotchkiss 2007). Among these, silane monolayer using 3-aminopropylyl triethoxy silane (APTES), 3-aminopropylyl trimethoxy silane (APTMS), N-[3-(trimethoxysilyl) propyl]ethylenediamine (TMSPED), and 3-glycidoxy propyl trimethoxy silane (GOPS) for the functionalization of the amine and the epoxy groups on the PS plate and the GS surfaces (Huang et al 2012;Moirangthem et al 2012;Wang and Vaughn 2008;Yang et al 2005;Lin et al 2006;Kobayashi et al 2007;Dixit et al 2011). APTES functionalized PS plates and GS are used in the immobilization of antibodies for the detection of antigens.…”

Mycofabrication of common plasmonic colloids, theoretical considerations, mechanism and potential applications

“…Moirangthem et.al. [32] has presented ultrasensitive LSPR sensor based on AuNPs coated with anti-human epidermal growth factor receptor (anti-EGFR) and partially embedded in transparent substrate. The device was able to detect the receptor in concentrations as low as 20 pM.…”

Adapting Bobbert-Vlieger model to spectroscopic ellipsometry of gold nanoparticles with bio-organic shells

“…Spectroscopic ellipsometry has been recently used for biosensing, in combination with plasmonics, whereby even small changes in optical properties produced by biofunctionalization or biorecognition can be detected and sometimes amplified [7,8]. Previous studies have shown that different polarization states of the light scattered and reflected by a sample can provide, with appropriate modeling, information about its optical properties, roughness and thickness [8][9][10].…”

“…Previous studies have shown that different polarization states of the light scattered and reflected by a sample can provide, with appropriate modeling, information about its optical properties, roughness and thickness [8][9][10]. In the context of scattering of light by a sphere placed on a surface, ellipsometric measurements are the most common and practical means of characterization.…”