Effects of an applied force on the association and dissociation of noncovalent specific interactions of macromolecules

• Main Authors: Jiang, Rui - Bin, 江瑞斌
• Other Authors: Lei, U
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/61316606701737276001

碩士 === 國立臺灣大學 === 應用力學研究所 === 92 === After applying a biosensor assay to assess the existence of some particular biomolecules, it is required that the sensing surface be regenerated before performing another course of assessment. In this thesis, we study theoretically the effects of forces through an applied electrical field on the association and the dissociation behavior of the biomolecule on biosensor surface. The dissociation behavior is affected by externally applied forces, and the association behavior is determined by the local concentration of the analytes. The course of regeneration is dominated by the dissociation behavior. We have tried three approaches for studying the dissociation. First, we considered that the dissociation is accomplished by tearing off the analyte from the ligand safely by the applied electrical force. We found that the required voltage is about several KVs, which is quite a large value for practical applications. Secondly, we considered that the dissociation is solely due to the bombardment of surrounding molecules to the combined analytes. The applied electric field exerts a drifting force on the free analytes, which drives them constantly away from the sensing surface. Thus the role of the applied field is to retard the association. We found that such drifting effect is minor in comparing with the flushing with clean buffer solution if the applied voltage is of order of volts. Thirdly, we proposed that the applied electric field can change the energy barrier for intermolecular force between the associated molecules. Such idea is incorporated with the classical Bell’s theory and the result agrees with the existing experiment. Thus the third approach may provide a physical explanation for the dissociation under an applied electric field.