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Tuesday, March 20, 2012

Hepatitis B surface antigen–antibody interactions studied by optical tweezers

Z.L. Zhou, B. Tang, A.H.W. Ngan, Z.N. Dong, and Y.S. Wu

The protein–protein interactions between hepatitis B surface antigen (HBsAg) and itsantibodies (anti-HBs) were studied by measuring the binding force between microspheres coated with such proteins using optical tweezers. The interaction force between the protein-coated microspheres was found to be strongly influenced by the acidity of the surrounding liquid medium, as well as the experimental temperature, and it reaches a maximum value at around pH 7.5 and temperature around 37°C. By measuring the protein distribution on the surfaces of the microspheres and their contact areas using scanning electron microscopy, the specific binding force between an HBsAg and anti-HBs protein pair is estimated to be around 4.8 pN at the optimum pH value and temperature at an applied loading rate of around 1 pN/s.

DOI

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