Proteins, adsorption, cell adhesion delivery

Some active materials are carriers for drugs (drug delivery systems), some have immobilized peptides to enable cell adhesion or migration, some are degradable by hydrolysis or by specific enzyme action. Some contain bioactive agents (e.g., heparin, thrombomodulin) to prevent coagulation or platelet activation while others incorporate bioactive groups to enhance osteo-conduction. Many include polyethylene oxide to retard protein adsorption and this is perhaps the closest we have come to a kind of inertness. 

In this study, the adsorption of polyelectrolytes, such as the class of PLL-g-PEG graft copolymers on metal oxide surfaces, was found to be consistent with the related observations from previous studies. In previous characterizations of the adsorption behavior of polyeleotrolytes on such metal oxide surfaces, polycations in particular, such as PLL, were found to form stable adsorbed layers on negatively charged oxides such as silicon dioxide and titanium dioxide. However, the class of PLL-g-PEG-based copolymers thus far had been evaluated only in the contexts of drug delivery and the reduction of cell adhesion without a thorough characterization of the related modified surfaces and their reduction of protein adsorption. 

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). 

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