Detection of Phosphopeptides by Localized Surface Plasma Resonance of Titania-Coated Gold Nanoparticles Immobilized on Glass Substrates

Abstract

We herein demonstrate a new sensing method for phosphopeptides by localized surface plasmon resonance (LSPR) using titania-coated gold nanoparticles immobilized on the surface of a glass slide as the sensing substrate and using UV-visible spectrophotometry as the detection tool. Titania has been known to be an effective substrate for binding with phosphorylated species. The detection principle is the shift of wavelength of optical absorption due to SPR of the gold nanoparticles induced by binding of phosphorylated species with titania on the surface of the gold nanoparticles. The feasibility of the approach is demonstrated by detection of tryptic digest products of beta-casein and milk. Gold nanoparticles coated with thin films of titania, immobilized on a glass slide, can selectively bind traces of phosphopeptides from complex samples, resulting in a wavelength shift of the absorption band in the SPR spectrum with good reproducibility. The LSPR results are confirmed by matrix-assisted laser desorption/ionization mass spectrometry. The detection limit for the tryptic digest product of beta-casein is 50 nM.

Gold nanoparticle-based biosensors

“…Secondly, the height of analytical response was inverse related to the affinity of the respective antibodies, which was consistent with the inversely proportional relationship between antibody affinity and binding capacity [20]. Since then, numerous labs have put effort into the work for correlating peak intensity and position of the surface plasmon absorbance of GNPs with the local refractive index of the surrounding medium [21][22][23][24][25][26][27][28][29][30][31], which is termed the localized surface Plasmon resonance (LSPR).…”

“…GNPs are considered to have the ability to amplify the SPR signals [25,[32][33][34][35][36][37][38][39][40][41][42]. Lin et al developed a fiber-based biosensor for organophosphorous pesticide determination utilizing the LSPR effect of GNPs [43].…”

“…They measured the absorption spectra of the GNP monolayers in which GNPs were immobilized upon a glass slide by a functional organic coupling agent and found an optical response to polymers of different refractive indexes that were spin-cast on the immobilized GNPs [26]. Subsequently, a series of papers from different labs have presented this chip-based format optical biosensor, in which GNPs are immobilized on an optically transparent substrate [22,23,25,[45][46][47][48][49]. For instance, Matsui et al demonstrated a SPR sensor chip for detection of small molecules like dopamine [47].…”

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

“…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.…”

Use of thermally annealed multilayer gold nanoparticle films in combination analysis of localized surface plasmon resonance sensing and MALDI mass spectrometry

“…This LSPR wavelength shift, which is based on the change in the refractive index, can be examined by using UV-vis transmission or reflection spectroscopy. Several types of LSPR sensing platforms have been reported such as substrates on which immobilized NPs from a colloidal solution, [10][11][12][13][14][15][16][17][18] lithographically fabricated triangular-nanocrystal arrays, [19][20][21][22][23][24][25][26][27][28] nanohole arrays produced by ion-beam lithography, [29][30][31][32] and transparent substrates on which metal island films are fabricated by vapor deposition. [33][34][35][36][37][38][39] When LSPR sensing is conducted in transmission mode, it is known as transmission localized surface plasmon resonance (T-LSPR) sensing.…”