Phosphate buffered saline adsorption

Adsorption of t-PA to process equipment surfaces consisting of either stainless steel or glass was minimized by adding the detergent polyoxyethylene sorbitan monooleate (Tween 80) to the semm-free culture conditioned media at 0.01% (vol/vol). The equipment was also rinsed, before use, with phosphate buffered saline (PBS) containing 0.01% Tween 80. Hydrophilic, plastic equipment was used whenever possible. AH buffers were sterile filtered. Sterile filtration of Hquids and gases is usually carried out using 0.2 or 0.45 p.m filters. 

For Yiv > YPv> where y v and Ypv are the surface tensions of liquid and protein, respectively, AFads increases with increasing ysv, predicting decreasing polymer adsorption. An example of this is phosphate buffer saline where y]v = 72.9 mJ/m2 and Ypv is usually between 65 and 70mJ/m2 for most proteins [5]. Therefore, supports for gel-permeation and affinity chromatography should be as hydrophilic as possible in order to minimize undesirable adsorption effects. 

Figure 6. Semi quantitative evaluation of spontaneous adsorption of collagen IV conjugated with a fluorescence marker Oregon Green 488 (A) to polyethylene foils iradiated with ions (energy 30 keV, dose from lO to lO ions/cm ), and its correlation with the number of rat aortic smooth muscle cells initially adhering to the polymer on day 1 after seeding (B). Collagen was diluted in phosphate-buffered saline to the concentration of 0.02 mg/ml (10 pg/cm ) and incubated with the foils for 24 h at room temperature. Mean+SEM from 4-9 experiments. Student t-test for unpaired data [43].

Song et al. have reported the determination of chlorpromazine by adsorptive stripping voltammetry [169]. Phosphate buffer saline solution (pH 7.4), consisting of 0.2 g KH2PO4,1.15 g Na2HP04,0.2 g KCl, 8 g NaCl, and 0.047 g MgCl2, was used as the supporting electrolyte. Two methods were reported for the determination of chlorpromazine ... 

The effects of conditioning layers of two important blood serum proteins, albumin and fibrinogen were investigated. Protein adsorption was studied using bovine serum albumin (BSA) and fibrinogen (F) from Sigma. The samples were incubated for 3 h at 37°C in solutions of albumin (1 mg/mL) and fibrinogen (0.2 mg/mL) prepared in phosphate buffered saline (PBS, 0.01 M phosphate buffer, 0.0027 M KC1, 0.137 MNaCl, pH 7.4). After the incubation period, the samples were rinsed 3 times with PBS and analyzed by the various surface characterization techniques. 

All solutions were made with analytical-grade reagents and low-conductivity (6 megohm) water purified by a combination of reverse osmosis, ion exchange, activated-carbon adsorption, and microfiltration. Phosphate-buffered saline (PBS)... 

In order to reduce the nonspedfic binding of D1 protein to hydrophobic surface of microtiter plate, the polystyrene surface was blocked by bovine semm albumin (BSA). Eu- labelled D1 protein (1 mg/ml) was incubated with different concentrations of atrazine (ITO -ITO M) for 1 h. The plate was washed 8 times by phosphate buffered saline (PBS), pH 7.5, followed by incubation with enhancing solution and measurement of fluorescence. Despite the high hydrophobic properties of D1 protein and Nylon, the adsorption of D1 protein on the Nylon 11 surface was 3-5 times smaller than on Nylon modified with melamine, which suggests that specific matrix contained herbicide molecules vras created. The binding reaction of the Eu- labelled D1 protein to spedfic polymer demonstrated some competitive effect in presence of atrazine but it was not sufficiently sensitive (Fig. 7). The maximum inhibition of binding reaction was in the range of 20%. 

Figure 2 Adsorption isotherms of four serum proteins to poly-tetrafluorethylene. Proteins dissolved at various bulk concentrations in phosphate buffered saline, pH 7.3 surface tension =72.0 ergs/cm. Proteins as indicated. (Reproduced with permission from Ref. 18. Copyright 1981, Elsevier/North Holland Press).

Although ATR has been used to quantify the variation in composition at the surface in TPEs (Sung and Hu, 1980), a related utility is its ability to monitor in situ processes such as reaction injection molding (RIM) (Ishida and Scott, 1986) and protein adsorption onto a polyurethane substrate (Pitt and Cooper, 1986). In the latter, the effect of shear rate on the kinetics of protein adsorption and desorption from phosphate-buffered saline (PBS) was studied in a specially designed flow cell. A very thin film of the commercial MDI-ED-PTMO polyurethane Biomer was cast from solution onto a Ge ATR prism. The thickness of the film was less than the penetration depth so the protein concentration could be monitored after the infrared absorption of the polymer... 

The adsorption method of fibrinogen is as follows each of the different PU beads was first contacted with bovine plasma containing C-labeled human fibrinogen as a function of adsorption time or plasma concentration. Sample was then rinsed with phosphate buffered saline (PBS, pH 7.4, 0.15M) twice and placed in 2% sodium dodecyl sulfate (SDS) solution for 2 days, and the surface concentration of fibrinogen was determined by counting the radioactivity. 

Figure 7 shows a human (milk) Lyso adsorption isotherm recorded on hydrophobic silica slides treated with dimethyldichlorosilane (DDS) [29]. Total internal reflectance fluorescence (TIRF) spectroscopy was used to assess the adsorbed mass of Lyso. The isotherm experiment was carried out at pH 7.4, with protein dissolved in a phosphate-buffered saline (PBS) (0.013 M KH2PO4, 0.054 Af Na2HP04) buffer including 0.1 M NaCl. Tables 8 and 9 show the relevant thermodynamic and regression data determined for this isotherm. 

The study of the phosphorus adsorption in the Changjiang River Estuary sediments showed that the sediments were buffers to phosphate and the balance time of phosphorus adsorption (desorption) was about 6 h. The saturated adsorption quantity of phosphorus was about 600 pg/g and the saturated desorption was about 126.37 pg/g. The apparent adsorption heat of fine sediments (AH) was 47.59 kJ/mol. The adsorption of phosphate was in accordance with Freundlich s isothermal equilibrium and it was a heat absorption reaction. The contents of sand and mud in sediments had some influence on adsorption and the adsorption would decrease with the increase in sand or mud content. In general, the increase in pH favors adsorption. Moreover, the increase in salinity does not favor adsorption but favors desorption. The research shows that the release of phosphorus in the sediments of the Changjiang River Estuary... 

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