反应详情

The coating process as described in Example 12 is repeated but instead of colouring 10 mM solution of biotin N-hydroxysuccinimide ester in dimethyl sulfoxide is added. After 2 hours of incubation, the tube is washed with dimethyl sulfoxide, ethanol and water, then dried. As a result of the treatment, biotin is bound by covalent bond to the free amino groups of the layer formed. Binding of the biotin was proved by titration with labelled 125I-streptavidine solution. 125I-streptavidin/PBS (Phosphate Buffered Saline) solution (pH 7,4) of 400,000 cpm/ml radioactive concentration is added into a piece of tube of 10 cm length and then it is incubated for 1 hour at ambient temperature. The composition of the PBS solution is as follows: 8 g NaCl, 0.2 g KCl, 1.15 g Na2HPO4.2H2O, 0.2 g KH2PO4, diluted with distilled water to a volume of 3 liters; pH is adjusted with NaOH to 7.4. After removing the titrant, the tube is washed three times with PBS solution (pH 7,4), then its radioactivity is measured. It was established that the tube has bound 97.4% of the labelled streptavidin. Consequently, the process described in the example is suitable for the formation of a layer containing functional groups; the layer can be modified by appropriate reagents.

1. additionis added
2. washthe tube is washed with dimethyl sulfoxide, ethanol and water
3. customdried