Biological Environment polymer surface interactions

Adsorbed proteins can greatly influence cellular reactions with synthetic materials. The sensitivity to adsorbed proteins, the variation in cellular response to specific proteins, and the rapid adsorption of proteins to all surfaces exposed to the biological environment, have led to the idea that the cellular response to implanted polymers is the result of specific interactions between components of the adsorbed protein layer on the polymer and the cell periphery. These observations, in turn, have led to the hypothesis that cellular interactions with foreign materials are controlled by the presence at the surface of specific proteins at sufficiently high surface density and degree of reactivity to elicit a response. Each of these factors constitutes an important aspect of the organization of the adsorbed protein layer. 

Both biomolecule doping and entrapment are likely to maintain CP biofunctionality for a longer period than if the biological molecules are adsorbed to the polymer surface postprocessing. Adsorption relies on ionic interactions at a material surface which dynamically alters when placed in a biological environment. The presence of molecules with stronger affinities for either the target molecule or the CP will result in displaeement of the biomolecule from the CP surface. 

In this review, recent advances in polymer/(nano)HAp composites and nanocomposites for bone tissue regeneration are presented, including specific subjects associated with polymer/HAp composition, molecular orientation and morphology, surface modification, and interactions between components and the biological environment. 

With further understanding how molecular rotors interact with their environment and with application-specific chemical modifications, a more widespread use of molecular rotors in biological and chemical studies can be expected. Ratiometric dyes and lifetime imaging will enable accurate viscosity measurements in cells where concentration gradients exist. The examination of polymerization dynamics benefits from the use of molecular rotors because of their real-time response rates. Presently, the reaction may force the reporters into specific areas of the polymer matrix, for example, into water pockets, but targeted molecular rotors that integrate with the matrix could prevent this behavior. With their relationship to free volume, the field of fluid dynamics can benefit from molecular rotors, because the applicability of viscosity models (DSE, Gierer-Wirtz, free volume, and WLF models) can be elucidated. Lastly, an important field of development is the surface-immobilization of molecular rotors, which promises new solid-state sensors for microviscosity [145]. 

Lipid-bilayer membranes on solid substrates are often used as cell-surface models connecting biological and artificial materials. They can be placed either directly on solids or on ultrathin polymer supports, such as brushes or hydrogels, which mimic the extracellular matrix. A similar approach has been applied to polymer membranes with the advantage of tunable thickness, easier chemical modifications to allow stimulus responsiveness, or the attachment of active molecules by incorporation of reactive end groups. In addition, incorporated proteins have lower interactions with the support because of the increased membrane thickness, and therefore behave as in a natural environment. ... 

The growth of the lyotropic liquid crystal precursor is very sensitive to the environment. Ozin and co-workers have shown that complex particle morphologies can result from growth of these mesoporous structures in quiescent solutions as diffusion fields and surface forces interact. Several workers have shown how the direction of the rods or plates of silica can be controlled. Polymers can be introduced to form composite structures that are very reminiscent of some biological composites. This does seem to parallel the proposed importance of liquid crystals in the growth of many biological structures. 

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