School of Chemical Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai, 200092, PR China.
Sci Rep. 2017 Jan 13;7:40772. doi: 10.1038/srep40772.
We created an immunosensing platform for the detection of proteins in a buffer solution. Our sensing platform relies on graphene oxide (GO) nanosheets conjugated with antibodies to provide quantitative binding sites for analyte proteins. When analyte proteins and standard fluorescein-labelled proteins are competing for the binding sites, the assay exhibits quantitative fluorescence quenching by GO for the fluorescein-labelled proteins as determined by the analyte protein concentration. Because of this mechanism, measured fluorescence intensity from unquenched fluorescein-labelled protein was shown to increase with an increasing analyte protein concentration. As an alternative to the conventional enzyme-linked immunosorbent assay (ELISA), our method does not require an enzyme-linked second antibody for protein recognition and the enzyme for optical signal measurement. Thus, it is beneficial with its low cost and fewer systematic errors caused by the series of antigen-antibody recognition steps in ELISA. Immune globulin G (IgG) was introduced as a model protein to test our method and our results showed that the limit of detection for IgG was 4.67 pmol mL in the buffer solution. This sensing mechanism could be developed into a promising biosensor for the detection of proteins, which would broaden the spectrum of GO applications in both analytical biochemistry and clinical diagnosis.
我们创建了一个用于在缓冲溶液中检测蛋白质的免疫传感平台。我们的传感平台依赖于与抗体共轭的氧化石墨烯 (GO) 纳米片，为分析物蛋白质提供定量结合位点。当分析物蛋白质和标准荧光素标记的蛋白质竞争结合位点时，该测定法通过 GO 对荧光素标记的蛋白质进行定量荧光猝灭，其荧光猝灭程度取决于分析物蛋白质的浓度。由于这种机制，从未猝灭的荧光素标记的蛋白质中测量的荧光强度随着分析物蛋白质浓度的增加而增加。与传统的酶联免疫吸附测定法 (ELISA) 相比，我们的方法不需要用于蛋白质识别的酶联第二抗体和用于光学信号测量的酶。因此，它具有成本低的优势，并且由于 ELISA 中的一系列抗原 - 抗体识别步骤引起的系统误差较少。免疫球蛋白 G (IgG) 被引入作为模型蛋白来测试我们的方法，我们的结果表明 IgG 在缓冲溶液中的检测限为 4.67 pmol mL。这种传感机制可以开发成一种用于检测蛋白质的有前途的生物传感器，这将拓宽 GO 在分析生物化学和临床诊断中的应用范围。
