A negative correlation between water content and protein adsorption on polymer brushes

Area of Science:

• Surface Science
• Polymer Chemistry
• Biomaterials

Background:

• Protein adsorption on surfaces is a critical factor in biomaterial performance and biocompatibility.
• Understanding the interplay between surface hydration and protein interactions is essential for designing advanced materials.

Purpose of the Study:

• To quantitatively investigate the correlation between water content and protein adsorption on various polymer brushes.
• To determine how surface-bound water influences protein interactions with different polymer architectures.

Main Methods:

• Utilized quartz crystal microbalance with dissipation (QCM-D) and surface plasma resonance (SPR) for quantitative analysis.
• Employed model polymer systems including poly N-isopropylacrylamide (PNIPAM), polyethylene glycol (PEG), poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(2,2,3,4,4,4-hexafluorobutyl)methacrylate (PHFBMA).
• Studied the adsorption of model proteins like bovine serum albumin (BSA) and fibrinogen (Fg).

Main Results:

• A clear negative correlation was observed between the water content within polymer brushes and the extent of protein adsorption.
• Higher hydrodynamic water content within the brushes led to a significant suppression of protein adsorption.
• For PNIPAM brushes with sufficient grafting density and water content exceeding 250 ng cm⁻², protein adsorption was found to be negligible.

Conclusions:

• Surface-bound water plays a crucial role in modulating protein adsorption on polymer brush surfaces.
• Tailoring the water content of polymer brushes is a viable strategy to control protein interactions and enhance biomaterial performance.
• PNIPAM brushes demonstrate potential for creating highly protein-repellent surfaces.