Phosphate-buffered saline buffer solution

Fig. 10. Hydrolysis of polymeric drugs having 5-FU at 37 °C (O) poly(VBFU), (A) poly(VBFU-co-MAn) in a 0.1 M phosphate buffer solution (pH 7.0), and ( ) poly-(VBFU), (A)poly(VBFU-co-MAn) in a physiological saline solution...

To prevent hemolysis of the blood in the hydrogel tubes, it was necessary to keep the gel pH and salinity equivalent to that of blood. This was done by adjusting the pH of the monomer solution to 7.38 by phosphate buffer solution and 0.85% of sodium chloride was added. 

Affinity purified antibodies to E. coli or Salmonella (KPL, Inc., Gaithersburg, MD) were immobilized on the surface of Nylon membranes (courtesy of Pall Corporation, NY) as follows. The Nylon membranes were cut into 1 cm discs and placed into separate wells of a polystyrene plate. Each membrane was incubated (while shaking) for 1 hour in 1 mL of 10% (w/v) caibodiimide solution (pH 5.0). The membranes were washed 3 times (3 minutes each) in 20 mM phosphate buffer solution (pH 5.6). The membranes were transferred to a new polyst)n ene plate and left 3 minutes to dry. Then, 20 pi stock solution (1 mg/ml) of anti-. coli or m -Salmonella antibodies were dropped onto each membrane and left to dry. Following that, each membrane was incubated for 2 hours with 2 ml of 0.5% BSA solution in 20 mM phosphate buffer, pH 5.6. The membranes were then washed 3 times as described above, incorporated into the disposable immunofiltration column and stored at 4 °C until further use. Mortalized bacteria were used in this study for safety reasons and to ensure a static (non-proliferating) sample population for quantitative purposes. Reference quantification of mortaliz bacteria samples were performed by hemacytometer counts and used to prepare stock bacterial suspensions in phosphate-buffered saline. 

HEPES-buffered saline or BES-buffered saline is mixed with DNA. The result is a precipitate that distributes throughout the cell culture. Uptake of the precipitate, and consequently the DNA, is believed to be achieved through phagocytosis [12]. An important issue affecting transfection efficiency for this method is the pH of the phosphate buffer solution. The pH of the buffer should be maintained between 6.95 as in BES-buffered saline and 7.1 as in HEPES-buffered saline. In addition, the quality of the precipitate must be uniform and removed after incubation. Calcium phosphate coprecipitation works for both transient and stable transfections in numerous cell lines, both adherent and suspension. 

FIGURE 9.4 Circular dichroistn (CD) spectrum of dilute solution (0.24 mg/mL) of recombinant resilin in phosphate-buffered saline (PBS). (From Whelan, A.J. and Robinson, A.J., unpublished data). 

In a subsequent study, the effect of reducing the ELP molecular weight on the expression and purification of a fusion protein was investigated. Two ELPs, ELP [V-20] and ELP[VsA2G3-90], both with a transition temperature at 40°C in phosphate-buffered saline (PBS) containing 1 M NaCl, were applied for the purification of thioredoxin. Similar yields were observed for both fusion proteins, resulting in a higher thioredoxin yield for the ELP[V-20] fusion, since the ELP fraction was smaller. However, a more complex phase transition behavior was observed for this ELP and therefore a selection of an appropriate combination of salt concentration and solution temperature was required [39]. 

The specifications and standardization include raw materials, preparation method of the standard solution, concentration of proteins, and the main band on SDS-PAGE. The outline of the procedure for preparation of the calibrators is shovm in Eig. 4.2. Table 4.5 shows the raw materials and the preparation method of the initial extract. To prepare the calibrators, the raw materials are extracted by the standard solution containing SDS and mercaptoethanol. The initial extract is prepared by centrifugation and filtration of the extract. The diluted extract is then prepared by 10-fold dilution of the initial extract with phosphate-buffered saline (PBS pH 7.4). The protein concentration of the diluted extract is assayed using the 2-D Quant kit (Amersham Bio Sciences). The standard solution is then... 

Enzyme-linked immunosorbent assay (ELISA). Li and Li developed an ELISA procedure for imidacloprid to determine its residues in coffee cherry and bean extracts. A 25-g amount of sample extracted with 300 mL of methanol and 1% sulfuric acid (3 1, v/v) for 3 min. An aliquot of the sample extract (0.5 mL) is mixed with 1 mL of water and a gentle stream of nitrogen is used to evaporate methanol. The solution is then extracted with 1 mL of ethyl acetate, the extract is reconstituted in 1 mL of PBST (phosphate-buffered saline containing 0.05% Tween 20) and competitive ELISA is performed to quantify imidacloprid in the extract. Eor methanol extracts of coffee cherries and beans fortified with imidacloprid at 0.5 mgL recoveries of imidacloprid by the ELISA method were 108 and 94, respectively. 

Preparations of PEG-modified proteins. A. SC-PEG (1 g, 0.2 mmol) was added to a stirred solution of Bovine Serum Albumin (BSA) (100 mg, 1.5 x 10 6 mol) in 0.1 M sodium phosphate, pH 7.8 (60 mL). Sodium hydroxide (0.5 N) was used to maintain pH 7.8 for 30 min. The excess of free PEG was removed by diafiltration using 50 mM phosphate buffered saline. Approximately 30 amino groups of the native protein were modified as determined by trinitrobenzenesulfonate (TNBS) assay (28). The same degree of modification was obtained when the experiment was repeated under identical conditions using SS-PEG instead of SC-PEG. 

Figure 4. AFM micrograph of a saturated monolayer of antibodies against p2-microglobulin measured in phosphate buffered saline (PBS) solution using tapping mode. The dark window shows the underlying polystyrene surface obtained by wipping off the antibodies.

Fig. 10. Controlled release of insulin in vitro from P(MAA-g-EG) microparticles simulated gastric fluid (pH = 1.2) for the first two hours and phosphate buffered saline solutions (pH = 6.8) for the remaining three hours at 37°C (243).

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