Department of Chemistry, Wuhan University, Wuhan 430072, China.
Analyst. 2013 May 7;138(9):2661-8. doi: 10.1039/c3an36400c.
Based on the fluorescence resonance energy transfer (FRET) and fluorescence anisotropy (FA), the present study reported proof-of-principle for a highly sensitive and rapid detection technique that can be precisely utilized for investigating the self-assembly of polydeoxyadenylic acid (poly(dA)) and β-glucan, and the interactions of the poly(dA)-β-glucan complex on the surface of graphene oxide (GO). Due to the noncovalent assembly of fluorescein amidite (FAM)-labeled poly(dA) and GO via π-π stacking, the fluorescence of (FAM)-labeled poly(dA) as a molecular aptamer beacon (MAB) was completely quenched by GO. Conversely, the addition of single-stranded lentinan (s-LNT) resulted in the significant restoration of fluorescence due to the formation of poly(dA)-s-LNT complexes with a stiff rod-like structure, which had a weak affinity to GO and kept the dyes away from GO. However, relatively weak fluorescence restoration was observed by adding another single-stranded curdlan (s-CUR) for positive control, indicative of complex formation with higher binding ability to GO. The fluorescence anisotropy (FA) was also combined to confirm the occurrence with different increments of anisotropy relative to the free poly(dA), which could be conveniently extended for detecting the assembly of other biomolecules with higher sensitivity.
基于荧光共振能量转移（FRET）和荧光各向异性（FA），本研究报告了一种高灵敏度和快速检测技术的原理验证，该技术可精确用于研究聚脱氧腺苷酸（poly(dA)）和β-葡聚糖的自组装，以及 poly(dA)-β-葡聚糖复合物在氧化石墨烯（GO）表面的相互作用。由于荧光素胺（FAM）标记的 poly(dA)通过π-π堆积非共价组装到 GO 上，作为分子适体探针（MAB）的（FAM）标记的 poly(dA)的荧光完全被 GO 猝灭。相反，加入单链香菇多糖（s-LNT）会由于形成具有刚性棒状结构的 poly(dA)-s-LNT 复合物而导致荧光显著恢复，该复合物与 GO 的亲和力较弱，并使染料远离 GO。然而，添加另一种单链昆布多糖（s-CUR）作为阳性对照时，观察到相对较弱的荧光恢复，表明与 GO 具有更高结合能力的复合物形成。还结合了荧光各向异性（FA）来确认发生了不同程度的各向异性相对于游离的 poly(dA)，这可以方便地扩展用于检测其他具有更高灵敏度的生物分子的组装。
