Protein interactions with polyelectrolyte multilayers: interactions between human serum albumin and polystyrene...

Area of Science:

• Materials Science
• Biophysics
• Surface Chemistry

Background:

• Protein adsorption on surfaces is crucial in biomaterial applications.
• Polyelectrolyte multilayers (PEMs) offer tunable surface properties.
• Understanding protein-surface interactions is key for controlling biological responses.

Purpose of the Study:

• To investigate the adsorption behavior of human serum albumin (HSA) on polystyrenesulfonate (PSS)/polyallylamine (PAH) multilayers.
• To elucidate the influence of multilayer surface charge and ionic strength on HSA adsorption.
• To explore the adsorption/desorption dynamics and underlying electrostatic interactions.

Main Methods:

• Fabrication of PSS/PAH multilayers.
• Scanning Angle Reflectometry (SAR) for in-situ thickness measurements.
• Controlled variation of ionic strength and protein concentration during adsorption/desorption experiments.

Main Results:

• HSA adsorbs on both PSS (negative) and PAH (positive) terminated surfaces.
• PAH-terminated surfaces result in significantly thicker protein films (up to 4x native albumin size).
• Adsorption is strongly dependent on ionic strength, with distinct behaviors for PSS and PAH terminations, and exhibits limited desorption in pure buffer but significant desorption in higher ionic strength buffer.

Conclusions:

• Protein adsorption is a complex process driven by competing electrostatic interactions.
• PEM surface charge and solution ionic strength are critical parameters controlling HSA adsorption.
• Proposed microscopic models explain the observed adsorption/desorption phenomena.