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If one needs to monitor the concentration of glucose, for example, in the bloodstream using an in vivo biosensor, it involves electrochemical or spectroscopic techniques.
One ongoing project, in collaboration with ~Linda Luck in Clarkson's Chemistry Department, involves the use of atomic force microscopy and quatz microbalance to study a periplasmic glucose/galactose binding protein, GGRQ26C. So far the nature of this receptor-glucose interaction was not clear. Here we have found that the receptor protein film immobilized on the gold surface increases its rigidity when glucose is added, which explains the unexpected detection signal. To study the rigidity change, we developed a new fast and simple method based on using atomic force microscopy (AFM) in tapping mode. The method was verified by explicit measurements of the Young’s modulus of the protein film by conventional AFM methods. Since there are a host of receptors that undergo structural change when activated by ligand, AFM can play a key role in the development and/or optimization of biosensors based on rigidity changes in biomolecules.
.Igor Sokolov, Venkatesh Subba-Rao, and Linda A. Luck, ~Change in Rigidity in the Activated Form of the Glucose/ Galactose Receptor from E-coli: A Phenomenon That Will Be Key to the Development of Biosensors, Biophysical Journal, Biophysical Journal 2006; 90(3):1055-63.
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