Cell adhesion and protein adsorption

Biomatenals with Low Thromhogenicity. Poly(ethylene oxide) exhibits extraordinary inertness toward most proteins and biological macromolecules. The polymer is therefore used in bulk and surface modification of biomaterials to develop antithrombogenic surfaces for blood contacting materials. Such modified surfaces result in reduced concentrations of cell adhesion and protein adsorption when compared to the nonmodified surfaces. 

Cell Adhesion and Protein Adsorption on Gradient Surfaces... 

Hyaluronic acid on PU Grafting Platelet adhesion, cell behavior Static, in vitro Bovine serum and cells, human blood Decreased platelet adhesion and protein adsorption, viable and round-shape cell layer [95]... 

It is clear that there is a bright future for responsive polymer brashes in the field of biomedical applications. They provide a unique control over surfaces that is difficult to match by any other surface coating. They have been shown be able to control wettability, cell adhesion, bacterial adhesion, and protein adsorption, which provide many opportunities for functional coatings of medical implants, protein carriers, biosensors. 

In contrast to other analytical methods, ion-selective electrodes respond to an ion activity, not concentration, which makes them especially attractive for clinical applications as health disorders are usually correlated to ion activity. While most ISEs are used in vitro, the possibility to perform measurements in vivo and continuously with implanted sensors could arm a physician with a valuable diagnostic tool. In-vivo detection is still a challenge, as sensors must meet two strict requirements first, minimally perturb the in-vivo environment, which could be problematic due to injuries and inflammation often created by an implanted sensor and also due to leaching of sensing materials second, the sensor must not be susceptible to this environment, and effects of protein adsorption, cell adhesion, and extraction of lipophilic species on a sensor response must be diminished [13], Nevertheless, direct electrolyte measurements in situ in rabbit muscles and in a porcine beating heart were successfully performed with microfabricated sensor arrays [18],... 

Whitesides and coworkers describe the use of an elastomeric membrane to pattern proteins and cells on bacteriological polystyrene (PS), glass, and poly(dimethyl-siloxane) (PDMS) substrates [92], A patterned PDMS membrane was casted from lithographically structured photoresists and brought into close contact with the substrates (Fig. 6). When incubated with a solution of fibronectin (FN), adsorption of the cell-adhesion-mediating protein to the surface was restricted to the exposed areas. The membrane was peeled off and cells were seeded from a serum-free medium. Passivation to cell attachment of the untreated portions of the surface was achieved by adding 1% bovine serum albumin (BSA) to the cell-seeding medium, which... 

Cell lines usually cannot be successfully propagated in various synthetic media without supplemental (and, unfortunately, poorly characterized) serum components. This requirement for supplemental protein materials probably reflects—at least initially—the need for adsorbable proteinaceous constituents which will spontaneously accumulate at and favorably modify (for cell adhesion and propagation) the surfaces of the culture containers. There was essentially no spontaneous fllm adsorption from freshly prepared RPMI 1630 culture medium without... 

Many interesting correlations have been established between the critical surface tension of materials (or other approximations of surface free energy) and protein adsorption, cell adhesion, and thrombus formation (41-48). Unfortunately, very few studies in which a biological response has been related to a specific surface chemistry exist. One study in which such a relationship was established, demonstrated the power of the contact angle method in analyzing surface structure related to blood compatibility (40). The blood compatibility of Stellite alloy heart valves was not due to the alloy itself, but to the closely packed methyl group structure associated with a tallow polishing compound used to finish the valve. Very recently, the power... 

DeFife K M, Hagen K M, Clapper D L, et al. (1999). Photochemically immobilized polymer coatings effects on protein adsorption, cell adhesion, and leukocyte activation. Journal of Biomaterials Science. Polymer Edition. 10(10) 1063-1074. 

Hydrophilic coatings have also been popular because of their low interfacial tension in biological environments [Hoffman, 1981]. Hydrogels as well as various combinations of hydrophilic and hydrophobic monomers have been studied on the premise that there will be an optimum polar-dispersion force ratio which could be matched on the surfaces of the most passivating proteins. The passive surface may induce less clot formation. Polyethylene oxide coated surfaces have been found to resist protein adsorption and cell adhesion and have therefore been proposed as potential blood compatible coatings [Lee et al., 1990a]. General physical and chemical methods to modify the surfaces of polymeric biomaterials are listed in Table 40.7 [Ratner et al., 1996]. 

Fibronectin, vitronectin, and type 1 collagen are some of the most representative ECM proteins involved in cell adhesion processes, therefore adsorption studies with these proteins and the PLA/G5 composite material have been performed. Preliminary studies have shown that all proteins adhere better to the G5 (the most hydrophilic material) than to the other materials. Vitronectin presented the best adhesion with PLA (the most hydrophobic material), and the PLA/glass composite presented an intermediate behavior. Further experiments are being conducted to evaluate the direct impHcation of the main proteins present in ECM to regulate cell proliferation and differentiation in the studied materials, and to obtain information on how the quality of the surface (physicochemical and topographical) influences the adsorbed protein layer. 

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