Long Feng, Zhu Anna, Shi Hanchang, Wang Hongchen
School of Environment and Natural Resources, Renmin University of China , Haidian, Beijing 100872, China.
Anal Chem. 2014 Mar 18;86(6):2862-6. doi: 10.1021/ac500347n. Epub 2014 Mar 4.
A hapten-grafted graphene-based biosensor by integrating both the graphene nanosheets and immunoassay sensing technologies was developed for ultrasensitive homogeneous competitive immunoassay of small molecules. The structure of hapten-grafted graphene avoids the activity loss of biomolecules immobilized onto the graphene surface and is beneficial to preserve the binding affinity between small molecule and its specific antibody. The sandwich structure formed between hapten-grafted graphene nanosheets and fluorescence-labeled antibody increases the quenching efficiency of the organic dye, thereby resulting in high signal-to-background ratios and improved sensitivity for Bisphenol A (BPA) detection. On the basis of fluorescence resonance energy transfer (FRET) and homogeneous competitive immunoassay mechanism, high BPA concentrations in the sample reduce the amount of fluorescence-labeled anti-BPA antibody bound to graphene-BPA nanosheets, thus resulting in remarkable fluorescence signals. The linear quantification of BPA over concentration ranges from 0.5 to 50 nM with a detection limit determined as 0.12 nM. These findings show that the proposed method provides a powerful tool for the rapid and sensitive detection of small molecules in biological and environmental samples.
通过整合石墨烯纳米片和免疫分析传感技术，开发了一种半抗原接枝的基于石墨烯的生物传感器，用于小分子的超灵敏均相竞争免疫分析。半抗原接枝的石墨烯结构避免了固定在石墨烯表面的生物分子的活性损失，有利于保持小分子与其特异性抗体之间的结合亲和力。半抗原接枝的石墨烯纳米片与荧光标记抗体之间形成的夹心结构提高了有机染料的猝灭效率，从而导致高信噪比，并提高了双酚A（BPA）检测的灵敏度。基于荧光共振能量转移（FRET）和均相竞争免疫分析机制，样品中高浓度的BPA会减少与石墨烯-BPA纳米片结合的荧光标记抗BPA抗体的数量，从而产生显著的荧光信号。BPA在0.5至50 nM浓度范围内的线性定量，检测限确定为0.12 nM。这些发现表明，所提出的方法为快速、灵敏地检测生物和环境样品中的小分子提供了一个有力工具。
