Binding Kinetics of Biomolecule Interaction at Ultralow Concentrations Based on Gold Nanoparticle Enhancement

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• 作者：Li-Chen Su ; Ying-Feng Chang ; Chien Chou ; Ja-an Annie Ho ; Ying-Chang Li ; Li-Dek Chou ; Cheng-Chung Lee
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：May 1, 2011
• 年：2011
• 卷：83
• 期：9
• 页码：3290-3296
• 全文大小：831K
• 年卷期：v.83,no.9(May 1, 2011)
• ISSN：1520-6882

文摘

Measuring the kinetic constants of protein鈭抪rotein interactions at ultralow concentrations becomes critical in characterizing biospecific affinity, and exploring the feasibility of clinical diagnosis with respect to detection sensitivity, efficiency and accuracy. In this study, we propose a method that can calculate the binding constants of protein鈭抪rotein interactions in sandwich assays at ultralow concentrations at the pg/mL level, using a localized surface plasmon coupled fluorescence fiber-optic biosensor (LSPCF-FOB). We discuss a two-compartment model to achieve reaction-limited kinetics under the stagnant conditions of the reaction chamber. The association rate constant, dissociation rate constant, and the equilibrium dissociation constant, that is, k_a, k_d, K_D, respectively, of the kinetics of binding between total prostate-specific antigen (t-PSA) and anti-t-PSA at concentrations from 0.1 pg/mL to 1 ng/mL, were measured either in PBS or in human serum. This is the first time that k_a, k_d, and K_D have been measured at such a low concentration range in a complex sample such as human serum.