Accurate identification of exosomes plays an essential role in facilitating disease diagnosis and therapies. Herein, we proposed an Aptamer-cholesterol-mediated Proximity Ligation Assay (AcmPLA) for accurate identification of exosomes in a dual-probe strategy, one aptamer probe for recognition of exosomal innate surface protein CD63 and another cholesterol probe for biolipid layer targeting. By integrating a proximity ligation of probes bound with exosomal biomarkers for specific recognition and a rolling circle amplification (RCA) strategy for signal amplification, we have successfully developed an exosomes-surface approach that can perform “AND” logic analysis of dual biomarkers, which not only could be used for exosomes quantification, but also for exosomes tracing. Besides RCA-initiated signal amplification, CD9 antibody-labeled magnetic beads were used to capture exosomes for isolation and secondary signal enrichment. Our approach can achieve specific exosomes isolation and accurate identification and thus could be exploited for broad applications in biological science, biomedical engineering, and personalized medicine.

中文翻译：

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适体-胆固醇介导的邻近结扎测定法可准确鉴定外来体。

外泌体的准确鉴定在促进疾病诊断和治疗中起着至关重要的作用。在这里，我们提出了一种适体-胆固醇介导的邻近结扎测定法（AcmPLA），用于在双探针策略中准确鉴定外泌体，一种适体探针用于识别外泌体先天表面蛋白CD63，另一种胆固醇探针用于生物脂质层靶向。通过整合与外泌体生物标志物结合的探针的接近连接以进行特异性识别和滚动环扩增（RCA）策略进行信号放大，我们成功开发了一种外泌体表面方法，可以对双重生物标志物进行“ AND”逻辑分析，仅可用于外泌体定量，也可用于外泌体追踪。除了RCA启动的信号放大之外，CD9抗体标记的磁珠用于捕获外来体，以进行分离和二级信号富集。我们的方法可以实现特定的外泌体分离和准确鉴定，因此可以在生物科学，生物医学工程和个性化医学中得到广泛应用。