In vitro protein adsorption

Park JH, Bae YH (2002) Hydrogels based on poly(ethylene oxide) and poly(tetramethylene oxide) or poly(dimethylsiloxane) synthesis, characterization, in vitro protein adsorption and platelet adhesion. Biomaterials 23 1797-1808... 

In vitro protein adsorption studies are relevant to in vivo behavior in humans. 

Protein deposition on materials surface is dependent on chemical nature of the surface (hydrophilicity, hydrophobicity, charge density) and also on the size and chemical composition of the proteins exposed to the synthetic surface (2). Since different biological media are composed of rather different types of proteins, materials designed for specific in lant applications must be tested using those proteins most likely encoimtered in vivo. Materials used in contact leiis applications are generally tested for in vitro protein adsorption using an artificial tear fluid (ATF) containing mixtures of proteins and lipids that are commonly found in hximan tear fluid and in contact lens deposits (15, 16). A... 

Yuan, J., Yang, D.C., Birkmeier, J. and Stolzenbach, J. (1995) Determination of protein binding by in vitro charcoal adsorption. Journal of Pharmacokinetics and Biopharmaceutics, 23, 41-55. 

Despite these excellent in vitro results, little progress has been made in vivo. For instance, under clinical conditions, blood proteins have been demonstrated to adsorb extensively to a PEO coated polymer, in contrast to in vitro results [69], Also, in vivo research on PEO coatings in the oral cavity showed poor results [70], despite excellent in vitro reductions in salivary protein adsorption and oral bacterial adhesion to PEO coatings on glass and hydroxyapatite [70,71], Possibly, the durability of the thin layer of grafted PEO chains in the oral cavity was not sufficient over a clinically relevant time scale. 

Crotts G, Sah H, Park TG. Adsorption determines in-vitro protein release rate from biodegradable microspheres quantitative analysis of surface area during degradation. J Contr Rel 1997 47 101-111. 

Amosite UICC Horse spleen ferritin In vitro Ferritin adsorption Desorbed protein showed subunits of 13 and 15 kDa, aside from the 20 kDa subunit present in the native protein Fubini et aL (1997) E K)sed iron core of the absorbed protein can trigger Fenton-type reactions... 

A good example of a surface-modified lens is the Sola/Bames-Hind Hydrocurve Flite lens, introduced in 1986. The material for the commercial Hydrocurve lens, bufilcon A [56030-52-5] contains methacrylic acid and has a high affinity for protein and subsequent deposition. The surface of the Flite lens was chemically modified with the addition of diazomethane (190) to reduce the surface charge. In vitro testing demonstrated a decrease in protein adsorption (191). 

The overall distribution of lanthanides in bone may be influenced by the reactions between trivalent cations and bone surfaces. Bone surfaces accumulate many poorly utilized or excreted cations present in the circulation. The mechanisms of accumulation in bone may include reactions with bone mineral such as adsorption, ion exchange, and ionic bond formation (Neuman and Neuman, 1958) as well as the formation of complexes with proteins or other organic bone constituents (Taylor, 1972). The uptake of lanthanides and actinides by bone mineral appears to be independent of the ionic radius. Taylor et al. (1971) have shown that the in vitro uptakes on powdered bone ash of 241Am(III) (ionic radius 0.98 A) and of 239Pu(IV) (ionic radius 0.90 A) were 0.97 0.016 and 0.98 0.007, respectively. In vitro experiments by Foreman (1962) suggested that Pu(IV) accumulated on powdered bone or bone ash by adsorption, a relatively nonspecific reaction. On the other hand, reactions with organic bone constituents appear to depend on ionic radius. The complexes of the smaller Pu(IV) ion and any of the organic bone constituents tested thus far were more stable (as determined by gel filtration) than the complexes with Am(III) or Cm(III) (Taylor, 1972). 

Lestelius M, Liedberg B, Tengvall P (1997) In vitro plasma protein adsorption on co-functionalized alkanethiolate self-assembled monolayers. Langmuir 13 5900-5908... 

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],... 

The cellular uptake of AS-ODN is an energy-dependent process and takes place in a saturable and sequence-independent manner [120,121]. The exact mechanism of uptake remains controversial. From in vitro experiments, some authors have proposed that the uptake is endocytic and mediated by membrane receptor proteins. The receptor responsible for the cellular uptake of AS-ODNs was reported to consist of both a 30-kDa protein [122] and an 80-kDa membrane protein [121]. However, other workers have argued that AS-ODN binding to membrane proteins is relatively non-specific and is mostly charge associated, consistent with adsorptive endocytosis or fluid-phase pinocytosis [101]. As a result of these conflicting reports, it is unlikely that in vitro data can be safely extrapolated to what occurs in the intact organism. 

An A-B-A-type block copolymer (HEMA-St-HEMA) was shown to form a microdomain structure and to exhibit excellent blood compatibility in both in vitro and ex vivo examinations. For instance, the luminal surface of the HEMA-STY coated vascular graft was bare without detectable thrombi after 372-day implantation in dog carotid aortas. The excellent blood compatibility was discussed by taking results of the unique mode of protein adsorption of HEMA-STY surface into account. 

The extractability of I3IJ-labelled plasma albumin from bone pieces and from powdered bone has been compared after both in vivo and in vitro incorporation. Albumin is more readily extracted from bone pieces than from bone powder which implies that tissue disruption exposes additional protein adsorption sites. It has been suggested that incorporation of plasma albumin and other proteins into calcified matrix during bone formation occurs mainly as a result of its strong interaction with bone mineral237 239 240>. 

According to the results of our experiments in vitro, the highest adsorptive capacity with reference to proteins and protein-associated phospholipids and triglycerides of blood serum was characteristic of the highly disperse silica modified with aluminium oxide. The mechanism of the therapeutic effect of HDS on treatment for intestinal infections seems to involve the following major aspects. 

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