Self-assembly protein-polymer

CappeUo J., Crissman J.W., Crissman M., Ferrari F.A., Textor G., WaUis O., Whitledge J.R., Zhou X., Butman D., Auketman L., and Stedronsky E.R. In-situ self-assembling protein polymer gel systems for administration, deUvety, and release of drugs, J. Contr. Rel., 53, 105, 1998. 

For formation of self-assembled protein-polymer complexes, p-galactosi-dase was selected as a model protein. p-Galactosidase has a p7 of 4.6, thus possessing a net negative charge under physiological conditions, which allows for interactions with the positively charged polymers. The two reported SS-PAAs efficiently condensed this enzyme by self-assembly into... 

Sallach RE, Cui W, Balderrama F, Martinez AW, Wen J, Haller CA, Taylor JV, Wright ER, Long RC Jr, Chaikof EL (2009) Long-term biostability of self-assembling protein polymers in the absence of covalent crosslinkmg. Biomaterials 31 779-791... 

Self-assembly of polymers in the bulk Polymer micelles, polymero-somes, gelled macromole-cules, nano-tubes, protein fibres/tapes produced by aggregation at low pH, controlled release vehicles, smart delivery systems 50-500 nm Forster and Konrad, 2003 Sanguansri and Augustin, 2006 Dickinson 2006a Graveland-Bikker and de Kruif, 2006 van der Linden, 2006... 

Self-assembled supramolecular polymers and fibres based on proteins are ubiquitous biological building blocks... 

Keywords Elastinlike polymers Genetic engineering Protein-based polymers -Self-assembly Smart polymers... 

Milk is a natural colloidal dispersion that contains casein micelles, self-assembled protein associates with a diameter of about 200 nm [20]. The casein micelles are protected against flocculation by an assembly of dense hairs (often called a brush ) at their surfaces. Polymer brushes can thus provide steric stabilization of colloids. For millennia, man used the fact that milk flocculates and gels when it is acidified, as in yogurt production. Below pH = 5 macroscopic flocculation of the casein micelles in milk is observed [21]. This means that the interactions between casein micelles change from repulsive to attractive. The explanation is that acidification leads to collapse of the casein brushes [22]. In cheese-making the steric stabilization is removed by enzymes, which induce gelation into cheese curd. 

Samples, one half coated with SiOa and the other half with Ti02, were used for quantitative surface analysis after each of the siuface treatment steps (cleaning, self-assembly, and polymer and protein adsorption, section 2). These samples exhibit material contrast on a macroscopic scale and are discussed in section 3.1. Micropat-temed surfaces were subjected to identical siuface modification procedures and characterized qualitatively by imaging ToF-SIMS (section 3.2) and fluorescence microscopy (section 3.3) and were used in the cell experiments (section 3.4). In both types of samples, material contrast (on a macroscopic or microscopic scale, Figure la) is converted into contrast with respect to protein adhesion (Figure Ic) via a series of surface modification steps (self-assembly of DDP, adsorption of PLL-g-PEG section 2). 

In this chapter we describe the basic principles involved in the controlled production and modification of two-dimensional protein crystals. These are synthesized in nature as the outermost cell surface layer (S-layer) of prokaryotic organisms and have been successfully applied as basic building blocks in a biomolecular construction kit. Most importantly, the constituent subunits of the S-layer lattices have the capability to recrystallize into iso-porous closed monolayers in suspension, at liquid-surface interfaces, on lipid films, on liposomes, and on solid supports (e.g., silicon wafers, metals, and polymers). The self-assembled monomolecular lattices have been utilized for the immobilization of functional biomolecules in an ordered fashion and for their controlled confinement in defined areas of nanometer dimension. Thus, S-layers fulfill key requirements for the development of new supramolecular materials and enable the design of a broad spectrum of nanoscale devices, as required in molecular nanotechnology, nanobiotechnology, and biomimetics [1-3]. 

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