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Human serum albumin self-assembly on weak polyelectrolyte multilayer films structurally modified by pH changes.
Csilla Gergely1, Sophie Bahi, Balázs Szalontai
1Institut National de la Santé et de la Recherche Médicale, Unité 595, Faculté de Chirurgie Dentaire, Université Louis Pasteur, 11, rue Humann, 67085 Strasbourg Cedex, France.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 1, 2005
Summary
Protein adsorption onto polyelectrolyte films depends on pH and film termination. Unexpected human serum albumin uptake occurred on negatively charged films, possibly due to surface changes and protein structure.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Protein-Surface Interactions
Background:
- Protein adsorption on polyelectrolyte films is complex, influenced by electrostatic forces, hydrogen bonds, and hydrophobic interactions.
- The charge and accessibility of proteins are pH-dependent and affected by their secondary structure.
- Polyelectrolyte film buildup and protein adsorption are intricate processes influenced by multiple factors.
Purpose of the Study:
- To investigate the effect of pH on protein adsorption onto polyelectrolyte films.
- To examine the role of film-terminating polyelectrolyte and protein secondary structure in adsorption.
- To understand the adsorption behavior of human serum albumin (HSA) onto poly(L-lysine) (PLL) and poly(glutamic acid) (PGA) films.
Main Methods:
- Fabrication of multilayer polyelectrolyte films using poly(L-lysine) (PLL) and poly(glutamic acid) (PGA).
- Adsorption studies of human serum albumin (HSA) onto (PLL/PGA)n films across a pH range of 3.0-10.5.
- Analysis of polyelectrolyte film buildup and HSA adsorption based on pH, terminating layer, and protein characteristics.
Main Results:
- Polyelectrolyte film buildup was not solely dependent on the charges of individual polyelectrolytes.
- HSA adsorption was significantly influenced by the film's terminating polyelectrolyte.
- At low pH, PLL-terminated films showed repulsion of HSA, while at high pH, PGA-terminated films exhibited unexpected HSA uptake despite both being negatively charged.
Conclusions:
- Protein adsorption is a complex interplay of electrostatic, hydrogen bonding, and hydrophobic interactions, modulated by pH and protein secondary structure.
- Surface rugosity and changes in protein secondary structure at specific pH values can lead to unexpected adsorption behaviors.
- The terminating layer of polyelectrolyte films plays a critical role in dictating protein adsorption dynamics.