AFM-based Force Spectroscopy on Polystyrene Brushes: Effect of Brush Thickness on Protein Adsorption

Abstract

Herein we present a study on nonspecific binding of proteins at highly dense packed hydrophobic polystyrene brushes. In this context, an atomic force microscopy tip was functionalized with concanavalin A to perform single-molecule force spectroscopy measurements on polystyrene brushes with thicknesses of 10 and 60 nm, respectively. Polystyrene brushes with thickness of 10 nm show an almost two times stronger protein adsorption than brushes with a thickness of 60 nm: 72 pN for the thinner and 38 pN for the thicker layer, which is in qualitative agreement with protein adsorption studies conducted macroscopically by fluorescence microscopy.

Synthesis and Postpolymerization Modification of Thermoresponsive Coatings Based on Pentaerythritol Monomethacrylate: Surface Analysis, Wettability, and Protein Adsorption

“…It is known that surfaces modified with polystyrene [55] or substances with free carboxyl groups [56] have very good adsorption effectiveness, especially for BSA. On the other hand, the surfaces modified by ethers have often low-fouling properties [45,[57][58].…”

Superamphiphilic TiO2 Composite Surface for Protein Antifouling

“…To further investigate the protein–substrate interaction, adhesion force spectroscopy was applied to determine the adhesion force of proteins approaching the SAC surface and the uncoated silica surface (Figures S5 and S6, Supporting Information). [ 35,36 ] The AFM tip decorated with proteins approached the substrate, came into contact with the surface with a loading force of 1.60 ± 0.32 nN, and then retracted. The force–distance curves revealed two different rupture events on the SAC substrate and uncoated silica substrate (Figure 1e,f and Figure S7 (Supporting Information)).…”

Surface modification of polydopamine coated particles via glycopolymer brush synthesis for protein binding and FLIM testing

“…For exceedingly high grafting density glycopolymer brushes, only the terminal carbohydrate moieties would be involved in binding due to the inability for the lectin to diffuse down through the brush layer and would essentially behave as a flat surface. 23 Protein binding for densely packed glycopolymer brushes would not therefore exhibit the glycocluster effect, the ability for a lectin to present an enhanced binding affinity by interacting with multiple carbohydrate moieties on a polymer backbone. 24,25 Fluorescent lifetime imaging microscopy (FLIM) was employed to investigate the binding of fluorescently tagged Concanavalin A (FITC-ConA) to the glycopolymer brush coated PDA@SiO 2 particles.…”