Helical Conjugated Polyelectrolyte Aggregation Induced by Biotin鈥揂vidin Interaction
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- 作者：Danlu Wu ; Fude Feng ; Dongping Xie ; Yan Chen ; Weihong Tan ; Kirk S. Schanze
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2012
- 出版时间：June 21, 2012
- 年：2012
- 卷：3
- 期：12
- 页码：1711-1715
- 全文大小：350K
- 年卷期：v.3,no.12(June 21, 2012)
- ISSN：1948-7185
文摘
Fluorescence correlation spectroscopy (FCS) is applied to demonstrate avidin-induced cross-linking in a system consisting of a helical anionic conjugated polyelectrolyte (P1) and a biotin-tetramethylrhodamine (TMR) conjugate (2). In a previous study, we used fluorescence spectroscopy to demonstrate that 2 binds to P1 via intercalation of the TMR chromophore into the P1 helix. Addition of avidin to the P1/2 complex induces little change in the fluorescence of the system; however, FCS reveals a remarkable increase in the diffusion time of the P1/2 complex in the presence of avidin. This change is attributed to supramolecular polymer aggregates produced by cross-link formation between the biotin unit of intercalated 2 and avidin. Atomic force microscopy imaging provides evidence supporting the existence of these aggregates. The highly sensitive FCS method is used to develop a novel sensor for the biotin鈥揳vidin interaction, with a detection limit of <100 pM for avidin.