Institute of Microbial Technology (IMTECH), Council of Scientific and Industrial Research (CSIR), Chandigarh, India, 160036.
Department of Cardiology, PGIMER, Chandigarh, India, 160012.
Mikrochim Acta. 2022 Sep 2;189(10):366. doi: 10.1007/s00604-022-05461-9.
Bioreceptor functionalized metallic nano-colloids have been identified as effective nanobioprobes to realize the detection of an analyte based on a common phenomenon of salt-induced aggregation. In marked contrast to this, we describe a nano-sandwich assay integrating the novel match-pair of aptamer and peptide functionalized gold nanoparticles. The site-directed biomolecular interaction of high affinity aptamer and peptide bioreceptors directed towards distinct sites of cardiac biomarker troponin I; this was found to form a nano-sandwich assay in a peculiar manner. The gold nanoconjugates interact with specific and distant regions of troponin I to result in collision of probes upon target identification. In the presence of TnI, both nanobioprobes bind at their respective sites forming a nano-sandwich pair providing a visual color change from red to blue. Thus, the presence of target TnI itself causes instant agglomeration in just a single-step without addition of any external aggregator. The assay imparts 100% specificity and 90% sensitivity in a dynamic concentration range of 0.1-500 ng/mL troponin I with detection limit as low as 0.084 ng/mL. The applicability of the assay has been validated in clinical samples of acute myocardial infarction patients thus establishing a promising point-of-care detection of TnI.
生物受体功能化的金属纳米胶体已被鉴定为有效的纳米生物探针，可实现基于盐诱导聚集这一常见现象的分析物检测。与此形成鲜明对比的是，我们描述了一种整合新型适体和肽功能化金纳米粒子对的纳米三明治分析。高亲和力适体和肽生物受体针对心肌生物标志物肌钙蛋白 I 的不同位点的定向生物分子相互作用；以一种特殊的方式形成了纳米三明治分析。金纳米缀合物与肌钙蛋白 I 的特定和遥远区域相互作用，导致在靶标识别时探针发生碰撞。在 TnI 存在的情况下，两个纳米生物探针在各自的位点结合，形成纳米三明治对，提供从红色到蓝色的可见颜色变化。因此，目标 TnI 的存在本身会导致在没有添加任何外部聚集剂的情况下，在单个步骤中立即聚集。该分析在 0.1-500ng/mL 肌钙蛋白 I 的动态浓度范围内赋予 100%的特异性和 90%的灵敏度，检测限低至 0.084ng/mL。该分析已在急性心肌梗死患者的临床样本中得到验证，从而为 TnI 的即时床边检测建立了一种有前途的方法。
