Bovine serum albumin conformation on methyl and amine functionalized surfaces compared by scanning force microscopy

Abstract

We investigated the adsorption of albumin on chemically modified gold surfaces by scanning force microscopy operating both in contact and noncontact mode. The surface modification was performed with thiol-based self-assembling molecules carrying amine or methyl groups. The albumin on the aminoethanethiol-coated gold formed a uniform layer and single molecules could be distinguished. On the dodecanethiol-coated surface the protein adsorbed in aggregates or single isolated molecules depending on the incubation time. The width of the albumin molecule on both surface was similar, but the height was much lower on the amine than on the methyl surface. This was interpreted as a difference in the conformation of albumin depending on the substrate, and could explain the promotion of cell adhesion on amine-treated polymers coated with albumin.

Albumin adsorption on unmodified and sulfonated polystyrene surfaces, in relation to cell–substratum adhesion

“…Low solute BSA concentrations (typically 0.5 g/mL) were convenient for individual molecular height measurements by z-axis analysis of AFM images. The height of 2.0 nm (median value; see Table 1) is similar to those reported by other workers [46,47,50].…”

“…Individual BSA molecules appeared, albeit scarcely, for samples prepared with c equal 1-5 g/mL. Corresponding z-axis analysis allowed to determine the molecular height of 1.1 nm (median value; see Table 1), which was similar to the height reported by other authors for BSA molecules on hydrophilic surfaces [46,50,56]. This number should however be treated with care, and may in fact be lower, since the lowest measured value, z = 0.5 nm, approaches the detection limit.…”

Comparative studies of the interaction between ferulic acid and bovine serum albumin by ACE and surface plasmon resonance

“…The SPR sensorgram acquired from a control experiment in which the FA solution was allowed to be in contact with an aminoethanethiol-modified sensor chip is also shown. It has been reported that albumin molecules can uniformly adsorb onto aminoethanethiol monolayers preassembled onto gold surfaces [44]. After FA was injected, there was a rapid increase in the SPR response (i.e.…”

Optimization of incubation time of protein Tc85 in the construction of biosensor: Is the EIS a good tool?

“…Infrared-based techniques, X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), contact angle measurements, surface plasmon resonance (SPR), radiolabelling, and atomic force microscopy (AFM) have all been used to characterize SAMs [8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”