Abstract：
Highly sensitive and facile detection of low levels of protein markers is of great significance for the early diagnosis and efficacy monitoring of diseases. Herein, aided by an efficient tyramine-signal amplification (TSA) mechanism, we wish to report a simple but ultrasensitive immunoassay with signal readout on a portable personal glucose meter (PGM). In this study, the bioconjugates of tyramine and invertase (Tyr-inv), which act as the critical bridge to convert and amplify the protein concentration information into glucose, are prepared following a click chemistry reaction. Then, in the presence of a target protein, the sandwich immunoreaction between the immobilized capture antibody, the target protein, and the horseradish peroxidase (HRP)-conjugated detection antibody is specifically performed in a 96-well microplate. Subsequently, the specifically loaded HRP-conjugated detection antibodies will catalyze the amplified deposition of a large number of Tyr-inv molecules onto adjacent proteins through highly efficient TSA. Then, the deposited invertase, whose dosage can faithfully reflect the original concentration of the target protein, can efficiently convert sucrose to glucose. The amount of finally produced glucose is simply quantified by the PGM, realizing the highly sensitive detection of trace protein markers such as the carcinoembryonic antigen and alpha fetoprotein antigen at the fg/mL level. This method is simple, cost-effective, and ultrasensitive without the requirement of sophisticated instruments or specialized laboratory equipment, which may provide a universal and promising technology for highly sensitive immunoassay for in vitro diagnosis of diseases.
摘要：
高灵敏、简便地检测低水平的蛋白质标志物对于疾病的早期诊断和疗效监测具有重要意义。在这里，在有效的酪胺信号放大(TSA)机制的帮助下，我们希望在便携式个人血糖仪（PGM）上报告一种简单但超灵敏的免疫测定。在这项研究中,酪胺和转化酶（Tyr-inv）的生物结合物，作为将蛋白质浓度信息转换和放大为葡萄糖的关键桥梁，是在点击化学反应后准备的。然后，在靶蛋白存在的情况下，固定的捕获抗体之间的夹心免疫反应，目标蛋白，并且辣根过氧化物酶(HRP)缀合的检测抗体在96孔微孔板中特异性地进行。随后，特异性加载的HRP缀合的检测抗体将通过高效TSA催化大量Tyr-inv分子在相邻蛋白质上的放大沉积。然后，沉积的转化酶，其剂量可以如实反映目标蛋白的原始浓度，可以有效地将蔗糖转化为葡萄糖。最终产生的葡萄糖的量通过PGM简单地定量,实现了对fg/mL水平的癌胚抗原、甲胎蛋白抗原等微量蛋白标志物的高灵敏度检测。此方法简单,成本效益高,超灵敏，不需要复杂的仪器或专门的实验室设备，为疾病的体外诊断提供了一种高灵敏的免疫分析技术。
