Protein adsorption mechanism

Surveying the literature, it appears that the interfacial behavior of proteins is a controversial subject. The main reason is that many studies have been performed under insufficiently defined conditions and/or that conclusions have been drawn on the basis of too scanty experimental evidence. Furthermore, the theoretical description of adsorbed layers of simple, flexible polymers is still in its infancy (5,6). As the structure of proteins is much more complex than that of those simple polymers, theories of polymer adsorption need to be greatly extended to become applicable to proteins. Clearly, our current knowledge of protein adsorption mechanisms and of the structure of the adsorbed layer is far from complete. 

Jin J, Jiang W, Yin J, Ji X, Stagnaro P. Plasma proteins adsorption mechanism on polyethylene-grafted poly(ethylene glycol) surface by quartz crystal microbalance with dissipation. Langmuir 2013 29 6624-33. http //dx.doi.org/10.1021/la4017239. 

Choi, S., Choi, B. C., Xue, C., Leckband, D. E. (2013). Protein adsorption mechanisms determine the efficiency of thermally controlled ceU adhesion on poly (AJ-isopropylacrylamide) brushes. Biomacromolecules, 14, 92-100. 

Additional work is required to pinpoint the protein adsorption mechanism and to clarily the role of the protein. 

Because membrane filtration is the only currently acceptable method of sterilizing protein pharmaceuticals, the adsorption and inactivation of proteins on membranes is of particular concern during formulation development. Pitt [56] examined nonspecific protein binding of polymeric microporous membranes typically used in sterilization by membrane filtration. Nitrocellulose and nylon membranes had extremely high protein adsorption, followed by polysulfone, cellulose diacetate, and hydrophilic polyvinylidene fluoride membranes. In a subsequent study by Truskey et al. [46], protein conformational changes after filtration were observed by CD spectroscopy, particularly with nylon and polysulfone membrane filters. The conformational changes were related to the tendency of the membrane to adsorb the protein, although the precise mechanism was unclear. 

Recent reports describe the use of various porous carbon materials for protein adsorption. For example, Hyeon and coworkers summarized the recent development of porous carbon materials in their review [163], where the successful use of mesoporous carbons as adsorbents for bulky pollutants, as electrodes for supercapacitors and fuel cells, and as hosts for protein immobilization are described. Gogotsi and coworkers synthesized novel mesoporous carbon materials using ternary MAX-phase carbides that can be optimized for efficient adsorption of large inflammatory proteins [164]. The synthesized carbons possess tunable pore size with a large volume of slit-shaped mesopores. They demonstrated that not only micropores (0.4—2 nm) but also mesopores (2-50 nm) can be tuned in a controlled way by extraction of metals from carbides, providing a mechanism for the optimization of adsorption systems for selective adsorption of a large variety of biomolecules. Furthermore, Vinu and coworkers have successfully developed the synthesis of... 

Quiquampoix H, Abadie J, Baron MH, Leprinae F, Matumoto Pintro PT, Ratcliffe RG, Staunton S (1995) Mechanisms and consequences of protein adsorption on soil mineral surfaces. Proteins at Interfaces II 602 321-333... 

The underlying mechanism by which this substance binds and fractionates proteins is poorly understood. Protein adsorption is believed to involve interaction with both calcium and phosphate... 

Norde, W. and C.A. Haynes. 1995. Reversibility and the mechanism of protein adsorption. In Proteins at Interfaces II Fundamentals and Applications. T.A. Hor-bett and J.L. Brash, editors. American Chemical Society, Washington, D.C., 26 40. 

Problems of desorption and loss of activity encountered with natural heparin have led numerous workers to explore synthetic heparin-like polymers or heparinoids, as reviewed by Gebelein and Murphy [475, 514, 515]. The blood compatibility of 5% blended polyelectrolyte/polyfvinly alcohol) membranes was studied by Aleyamma and Sharma [516,517]. The membranes were modified with synthetic heparinoid polyelectrolytes, and surface properties (platelet adhesion, water contact angle, protein adsorption) and bulk properties such as permeability and mechanical characteristics were evaluated. The blended membrane had a lower tendency to adhere platelets than standard cellulose membranes and were useful as dialysis grade materials. 

There has been considerable effort on the prediction of secondary and tertiary structures of protein from the amino acid sequence using computeraided minimal potential energy calculations8). The question as to how a primary amino acid sequence begins to produce secondary and super-secondary structures and fold into its equilibrium tertiary structure and functional domains is a very active field of structural biochemistry. A related problem is the mechanism by which a protein unfolds or denatures 20) which is of fundamental interest in the protein adsorption process. 

Hoffman129 and Baier 13° have reviewed most of the hypotheses and mechanisms suggested for blood compatibility in general and for the role of protein adsorption in particular. The safest statement one can make is that protein adsorption is indeed important in the blood compatibility process, in the compatibility of soft contact lenses, in the stability and acceptance of intraocular lenses, in the soft tissue foreign body reaction 131), and in virtually all situations where solid surfaces come into contact with physiologic environments. 

Quiquampoix, H. 2000. Mechanisms of protein adsorption on surfaces and consequences for extracellular enzyme activity in soil. In Soil Biochemistry, Vol. 10 (J.-M. Bollag and G. Stotzky, Eds.), pp. 282-300. Marcel Dekker, New York. 

Quiquampoix, H., Abadie, J., Baron, M. H., Leprince, F., Matumoto-Pintro, P.T., Ratcliffe, R. G., and Staunton, S. (1995). Mechanisms and consequences of protein adsorption on soil mineral surfaces. In Proteins at Interfaces. Protein Adsorption on Soil Mineral Surfaces. Horbett, T. A., and Brash, J. L., eds., American Chemical Society Symposium Series 602, Washington, D.C., pp. 321-333. 

Tang, Q. Wang, Y.-L. Chang, and H. J. Dai, An investigation of the mechanisms of electronic sensing of protein adsorption on carbon nanotube devices , Journal of The American Chemical Society 126, 1563 (2004). 

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