Study of the interactions of proteins with a solid surface using complementary acoustic and optical techniques

Area of Science:

• Materials Science
• Biotechnology
• Chemical Engineering

Background:

• Membrane-based water treatment is crucial but hindered by biofouling.
• Controlling biofouling necessitates understanding early-stage protein-membrane surface interactions.

Purpose of the Study:

• To characterize in real-time the interactions between model proteins and a polymeric membrane surface.
• To investigate the adsorbed mass, water content, and viscoelastic properties of proteins on the membrane.

Main Methods:

• Combined acoustic quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR).
• Utilized bovine serum albumin (BSA) and avidin as model proteins.
• Employed a polysulfone (PSU) membrane as the reference surface.

Main Results:

• Both BSA and avidin irreversibly adsorbed onto the PSU surface.
• Irreversible adsorption amounts were 292 ng/cm(2) for BSA and 380 ng/cm(2) for avidin.
• BSA formed a thinner, rigid layer with 50% water content, while avidin formed a thicker, viscoelastic layer with 58% water content and greater conformational changes.

Conclusions:

• Protein adsorption characteristics significantly influence the formation and properties of the fouling layer.
• Distinct adsorption behaviors of BSA and avidin on PSU membranes offer insights into fouling mechanisms.
• Real-time characterization techniques are vital for understanding fouling initiation and developing control strategies.