Single-molecule imaging of protein adsorption mechanisms to surfaces

TL;DR

This study uses single-molecule imaging to distinguish and analyze the mechanisms of protein adsorption onto surfaces, revealing that solution deposition is the main pathway and that surface chemistry influences adsorption.

Contribution

It provides real-time visualization and analysis of individual protein-surface interactions, differentiating between adsorption mechanisms at the single-molecule level.

Findings

Solution deposition is the primary adsorption mechanism at low protein concentrations.

Hydrophilic surfaces can prevent streptavidin adsorption.

Single-molecule imaging reveals dynamic adsorption pathways.

Abstract

Protein-surface interactions cause the desirable effect of controlled protein adsorption onto biodevices as well as the undesirable effect of protein fouling. The key to controlling protein-surface adsorptions is to identify and quantify the main adsorption mechanisms: adsorptions that occur (1) while depositing a protein solution onto dry surfaces and (2) after the deposition onto wet surfaces. Bulk measurements cannot reveal the dynamic protein adsorption pathways and thus cannot differentiate between the two adsorption mechanisms. We imaged the interactions of single streptavidin molecules with hydrophobic fused-silica surfaces in real-time. We observed both adsorbed proteins on surfaces and diffusing proteins near surfaces and analyzed their adsorption kinetics. Our analysis shows that the protein solution deposition process is the primary mechanism of streptavidin adsorption onto surfaces at the sub-nanomolar to nanomolar protein concentrations. Furthermore, we found that hydrophilic fused-silica surfaces can prevent the adsorption of streptavidin molecules.