Interfacial Forces between Biocompatible Surfaces and Proteins
04 / 2006 - 03 / 2007
The uncontrolled, non-specific adsorption of proteins and cells on artificial constructs adversely affects a diverse range of fields, including the fouling of implants and contact lenses, the design of advanced drug delivery vehicles, the colonization of marine organisms on ship hulls and the fouling of industrially interesting surfaces like filtration membranes. Over the past decades there has been an extensive search for coatings that minimize the adhesion of biomolecules. One of the most attractive ways to prevent the adsorption of biological materials on surfaces is the preparation of hydrophilic films of poly(ethylene glycol) (PEG) derivatives. In addition, polysaccharides have also been considered as materials for anti-fouling coatings.
It is well known that electrostatic attraction or repulsion has an effect on protein interactions with surfaces. It is also known that the steric-entropic barrier properties of PEG and polysaccharide coatings are responsible for minimizing protein adsorption. However, it is not well understood, and very few data exist, what interfacial interactions are produced when a coated layer produces a combination of steric-entropic and electrostatic interfacial forces.
A strategy to obtain more insight in the forces that play a role in the (lack of) adsorption process is to counteract the repelling force due to the entropic effect by the introduction of charges. The current proposal aims to construct multilayered systems that are based on highly hydrophilic PEG and polysaccharide coated layers onto which small charged molecules will be grafted covalently in order to introduce controlled amounts of surface charge. The resultant total interfacial forces and their effects on protein interactions with the layer surfaces will be studied with colloid-probe atomic force microscopy and streaming potential measurements. A fundamental understanding of the interfacial forces that play a role in antifouling will enable the design and fabrication of novel biomaterial surfaces and coatings.