Polymer scaffold modifiers

The QAC modifications described in the previous section are bulk phase modifications to the polymer itself. Efforts have been undertaken to concentrate the contact killing moieties, such as QACs, to the surface of the polymer by using polymer scaffold modifiers (PSMs) (Kurt et al 2007 Makal et al 2006 Waschinski et al., 2008). These modifications are driven by low solubility and/or low surface energy (Luzinov et al., 2004). Kurt et al. (2007) used a hard-block/soft-block strategy, with the bulk PU as the hard block and the antibiotic-loaded PSM as the soft block. Alkylammonium polyoxetane telechelics (Figure 17.1) react with the hard block PU formed by the reaction of 4,4 -(methylene bis(p-cyclohexyl isocyanate) and 1,4-butanediol. 

Polymerization of modified monomers makes the polymerization itself more challenging, as polymerization parameters known for common monomers, such as copolymerization reaction rates, do not necessarily apply to pre-modified monomers. Post-polymerization functionahzation methods, however, enable the use of functionahties as the side-chain modifiers to a well-defined polymer backbone so that a variety of functional polymers can be produced through one single polymer scaffold. A major challenge of this method is that the modification step must be a clean... 

Neat polymers have been used extensively for drug delivery applications and as biomaterials that promote cell adhesion. In fact, some of the earliest polymer scaffolds were simply films that promoted cell adhesion and growth (Ito et al., 1991). Aljawish et al. synthesized surface-modified chitosan films and studied the degree of protein adsorption and cell adhesion onto the substtate. Heterogeneous surface morphology of the films improved protein adsorption and subsequently resulted in favorable cell attachment and spreading (Aljawish et al., 2014). Film thickness also played a role in increasing cell viability. It was discovered that thicker films resulted in better cell viabihty (Aljawish et al., 2014). 

Mann, B.K. and West, J.L., Cell adhesion peptides alter smooth muscle cell adhesion, proliferation, migration, and matrix protein synthesis on modified surfaces and in polymer scaffolds, J. Biomed. Mater. Res., 60, 86,2002. 

Polymer Nanocomposite Scaffolds Modified with Carbon Nanotubes for Tissue Regeneration... 

Polymer Nanocomposite Scaffolds Modified With Carbon Nanotubes for... 

Hu, Y., S. Winn, Krajbich, I., and Hollinger, J. O. 2003. Porous polymer scaffolds surface-modified with arginine-glycine-aspartic acid enhance hone cell attachment and differentiation in vitro. J Biomed Mater Res, 64A, 583-590. 

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