Proteins, adsorption, cell adhesion

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],... 

Keywords protein adsorption cell adhesion polymer brush surface modification biofouling PEO a-chymotrypsin IgG... 

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. 

Through a matrix Alkanethiols, polymer An Protein adsorption, cell adhesion 7,34-38,67... 

Silane Si, nanoporous Si Protein adsorption, cell adhesion 29-32... 

Polymerization PU with poly(MPC-co-BMA) side chain via macromonomer S5mthesis Protein adsorption Cell adhesion [87]... 

Surface properties of an implantable device are of critical importance since the first contact with the organism is mediated by the interface. This interaction is what drives the subsequent tissue and cellular events, including protein adsorption, cell adhesion, and inflammatory response (Castner and Ratner, 2002 Cole et ai, 2009 Stevens and George, 2005). Thus, instructive biointerfaces will first dictate the type of cell that attach and instruct the cell behavior through the motifs presented. Scaffold materials can be functionalized with bioactive molecules, to influence cell adhesion and regulate cell function, either by physical adsorption of specific biomolecules or by chemical immobilization. 

Even the van Oss-Good theory has been criticized, e.g. due to the very high basic values, but despite that it has found wide applicability in describing interfacial phenomena (interactions) involving polymers, paints, proteins and other complex systems (like polymer surface characterization, CMC determination of surfactants, protein adsorption, cell adhesion, enzyme-substrate interactions). 

DeFife KM, Shive MS, Hagen KM, Clapper DL, Anderson JM. Effects of photochemically immobilized polymer coatings on protein adsorption, cell adhesion, and the foreign body reaction to silicone rubber. J Biomed Mater Res 1999 44(3) 298-307. 

Fig. 4 The effect of proteins on cell adhesion, (a) Kretschmann configuration for SPR. (b) Reflectance (R) as a function of incident angle (9), before (black) and after (red) the adsorption of substances, (c) Left. Time course of SPR angle shift during exposure to culture medium supplemented with 2% FBS (solid line) and the fraction of adherent cells determined by TIRFM (circles) on NH2-SAM. The dashed line is a manual fit to the symbols, included simply as a guide [42]. Right The concentrations of serum proteins in FBS...

Functional biomaterial surfaces that absorb proteins minimally are desirable in prolonging the lifetime of medical implants and providing a clean background for introducing specific cell adhesion functionalities. Nonspecific protein adsorption occurs in various degrees to all surfaces, but more readily to hydro-phobic and positively charged surfaces. To date, the most effective way to minimize nonspecific protein and cell adhesion is to use surfaces comprised of chains of polyethylene oxide (PEO also named polyethylene glycol, or PEG). ... 

Benoit DSW, Anseth KS (2005) Heparin functionalized PEG gels that modulate protein adsorption forhMSC adhesion and differentiation. Acta Biomater 1 461 70 Benoit DSW, Dumey AR, Anseth KS (2007) The effect of heparin-functionalized PEG hydrogels on three-dimensional human mesenchymal stem cell osteogenic differentiation. Biomaterials 28 66-77... 

Surface modification with hydrophilic polymers, such as poly(ethylene oxide) (PEO), has been beneficial in improving the blo( compatibility of polymeric biomaterials. Surface-bound PEO is expected to prevent plasma protein adsoiption, platelet adhesion, and bacterial adhesion by the steric repulsion mechanism. PEO-rich surfaces have been prepared either by physical adsorption, or by covalent grafting to the surface. Physically adsorbed PEO homopolymers and copolymers are not very effective since they can be easily displaced from the surface by plasma proteins and cells. Covalent grafting, on the other hand, provides a permanent layer of PEO on the surface. Various methods of PEO grafting to the surface and their effect on plasma protein adsorption, platelet adhesion, and bacterial adhesion is discussed. 

From a clinical point of view, a biomaterial can be considered as blood compatible when its interaction with blood does not provoke either any damage of blood cells or any change in the structure of plasma proteins. Only in this case can it be concluded that this material fulfills the main requests of biocompatibility [9]. As a consequence of the non-specific protein adsorption and adhesion of blood cells, the contact of any biomaterial with blood often leads to different degrees of clot formation [22-24]. 

SAMs of alkanethiolates on gold provide excellent model systems for studies on interfacial phenomena (e.g., wetting, adhesion, lubrication, corrosion, nucleation, protein adsorption, cell attachment, and sensing). These subjects have been reviewed previously [125,183-185]. Here we focus on applications that involve using chemical synthesis of functional SAMs after their assembly. 

Protein and cell adhesions on PMPC brushes prepared by SI-ATRP. (a) Schematic illustration for fabrication of a patterned PMPC brush, (b) L929 fibroblast cell adhesion on patterned PMPC brush after 20 h. (c) FN adsorption on PMPC brush after 60 min. (Images (b) and (c). (Reprinted with permission from Iwata, R., et ah. Biomacromolecules, 5, 2308, 2004. Copyright (2004) American Chemical Society.)... 

Chen et al. utUized a direct chemical reaction with a given solution (wet treatment) to modify the surface of the silicone rubber. The presence of a layer of PEO on a biomaterial surface is accompanied by reductions in protein adsorption, and cell and bacterial adhesion. In order to obtain a PEO layer on top of the silicone rabber surface, the surface was firstly modihed by incorporating an Si-H bond using (MeHSiO) , and followed by PEO grafting to the surface using a platinum-catalyzed hydrosilylation reaction. These PEO-modified surfaces were demonstrated by fibrinogen adsorption both from buffer and plasma, as well as albumin adsorption from buffer. Reductions in protein adsorption of as much as 90% were noted on these surfaces. 

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