Investigation of pH-Induced Protein Conformation Changes by Nanomechanical Deflection

Publication year: 2014
Authors: Thakur G. †, Jiang K. †, Lee D. †, Prashanthi K. †, Kim S. †‡, Thundat T. †

 - Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2 V4, Canada
 - Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta T2N 1N4, Canada

Published in: Langmuir, 2014, Vol. 30 (8), p. 2109–2116
doi: 10.1021/la403981t

Broad-spectrum biosensing technologies examine sensor signals using biomarkers, such as proteins, DNA, antibodies, specific cells, and macromolecules, based on direct- or indirect-conformational changes. Here, we have investigated the pH-dependent conformational isomerization of human serum albumin (HSA) using microcantilevers as a sensing platform. Native and denatured proteins were immobilized on cantilever surfaces to understand the effect of pH on conformational changes of the protein with respect to the coupling ligand. Our results show that protonation and deprotonation of amino acid residues on proteins play a significant role in generating charge-induced cantilever deflection. Surface plasmon resonance (SPR) was employed as a complementary technique to validate the results.

MP-SPR keywords: HSA immobilization, pH-based biosensor, pH-induced conformational changes