title: Recognition kinetics of biomolecules at the surface of different-sized spheres.
abstract: Bead-based assay is widely used in many bioanalytical applications involving the attachment of proteins and other biomolecules to the surface. For further understanding of the formation of a sphere-biomolecule complex and easily optimizing the use of spheres in targeted biological applications, it is necessary to know the kinetics of the binding reaction at sphere/solution interface. In our presented work, a simple fluorescence analysis method was employed to measure the kinetics for the binding of biotin to sphere surface-bound FITC-SA, based on the fact that the fluorescence intensity of FITC was proportionally enhanced by increasing the binding amount of biotin. By monitoring the time-dependent changes of FITC fluorescence, it was found that the binding rate constant of biotin to sphere surface-immobilized FITC-SA was much smaller than that of biotin to freely diffusing FITC-SA. This can be attributed to the decreased encounter frequency of the reaction pair, restricted motion of the attached biomolecule, and the weakened steric accessibility of the binding site. These factors would become more obvious when increasing the size of the sphere upon which the FITC-SA was immobilized. Additionally, the effect of nanoparticles on the diffusion-controlled bimolecular binding reaction was more evident than that on the chemical recognition-controlled binding reaction.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, P. R. China; National Engineering Research Center for Nanomedicine, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, P. R. China.
authors.forename: Cong-Ying
authors.initials: CY
authors.lastname: Wen
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, P. R. China.
authors.forename: Zhi-Ling
authors.initials: ZL
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, P. R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Xie
authors.affiliation: School of Life Science and Technology, Beijing Institute of Technology, Beijing, P. R. China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Xie
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, P. R. China. Electronic address: dwpang@whu.edu.cn.
authors.forename: Dai-Wen
authors.initials: DW
authors.lastname: Pang
mesh_terms: D001710:Biotin / Q000737:chemistry*; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry*; D008863:Microspheres; D019809:Streptavidin / Q000737:chemistry
chemical_list: D001710:Biotin; D019809:Streptavidin; D016650:Fluorescein-5-isothiocyanate