Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul 136-713, Republic of Korea.
Biosens Bioelectron. 2011 Oct 15;28(1):378-85. doi: 10.1016/j.bios.2011.07.052. Epub 2011 Jul 28.
We synthesized a three-dimensional nanorod structure of zinc oxide (ZnO) using a simple sol-gel process and systematically investigated properties of the ZnO nanorods regarding protein adsorption and effect on fluorescence emission. As compared to conventional polystyrene plate that has been widely used for strong protein adsorption, the ZnO nanorods had a superior protein adsorption capacity and significantly amplified fluorescence emission, suggesting the ZnO nanorods are attractive for fluorescence-based biomolecular detection assays. When applied to diagnostic assay of rheumatoid arthritis (RA) using cyclic citrullinated peptide (CCP) probe with a RCGRS motif that reportedly has a strong affinity for ZnO, the ZnO nanorods gave apparently high positive signals for all the RA-positive standards and patient sera, whereas upon the detection using conventional polystyrene plate, all the detection signals were relatively negligible. Moreover, the streptavidin-mediated immobilization of well oriented CCP further enhanced sensitivity, even for a 5000-times diluted patient serum. A highly sensitive detection of a very small amount of RA autoantibodies is important because individuals at high risk of developing RA can be identified several years before the clinical onset. Consequently, the fluorescence-based sensitive assay of RA was successfully performed using the three-dimensional ZnO nanorods, owing to the fluorescence amplification and protein/peptide adsorption properties and dimensionality of ZnO nanorods that in turn increases probe accessibility to anti-CCP RA autoantibodies. Although RA was assayed here for proof-of-concept, the ZnO nanorods-based assay can be applied in general to sensitive detection of a wide variety of antibody or protein targets.
我们使用简单的溶胶-凝胶法合成了氧化锌（ZnO）的三维纳米棒结构，并系统地研究了 ZnO 纳米棒的性质，包括蛋白质吸附和对荧光发射的影响。与传统的广泛用于强蛋白质吸附的聚苯乙烯板相比，ZnO 纳米棒具有优越的蛋白质吸附能力，并显著放大了荧光发射，这表明 ZnO 纳米棒在基于荧光的生物分子检测中具有吸引力。当将其应用于使用具有报道的与 ZnO 强亲和力的环瓜氨酸肽（CCP）探针的类风湿关节炎（RA）诊断检测时，ZnO 纳米棒对所有 RA 阳性标准品和患者血清均给出了明显的高阳性信号，而使用传统的聚苯乙烯板进行检测时，所有检测信号都相对较小。此外，链霉亲和素介导的定向 CCP 固定进一步提高了灵敏度，即使对于稀释了 5000 倍的患者血清也是如此。对少量 RA 自身抗体进行高灵敏度检测很重要，因为在临床发病前几年就可以识别出发生 RA 的高危个体。因此，由于 ZnO 纳米棒的荧光放大和蛋白质/肽吸附特性以及维度增加了对抗-CCP RA 自身抗体的探针可及性，成功地使用三维 ZnO 纳米棒进行了基于荧光的 RA 敏感检测。虽然这里只检测了 RA，但基于 ZnO 纳米棒的检测方法可以一般应用于对各种抗体或蛋白质靶标的敏感检测。
