Detection of Secretion of Exosomes from Individual Cell in Real-Time by Multifunctional Nanoelectrode-Nanopore Nanopipettes

Highly Sensitive Detection of Tumor Cell-Derived Exosomes Using Solid-State Nanopores Assisted with a Slight Salt Gradient

As an important biomarker, tumor cell-derived exosomes have substantial application prospects in early cancer screening and diagnosis. However, the unsatisfactory sensitivity and complicated sample pretreatment processes of conventional detection approaches have limited their use in clinical diagnosis. Nanopore sensors, as a highly sensitive, label-free, single-molecule technology, are widely utilized in molecule and bioparticle detection. Nevertheless, the exosome capture rate through nanopores is extremely low due to the low surface charge densities of exosomes and the effects of electrolyte concentration on their structural stability, thereby reducing the detection throughput. Here, we report an approach to improve the capture rate of exosome translocations using silicon nitride (SiNx) nanopores assisted by a slight salt electrolyte gradient. Improvements in exosome translocation event frequency are assessed in electrolyte solutions with different concentration gradients. In the case of asymmetric electrolytes (cis1× PBS and trans0.2 M NaCl, 1× PBS), the event frequency of tumor cell (HepG2)-derived exosome translocations is enhanced by nearly 2 orders of magnitude while maintaining vesicle structure stability. Furthermore, benefiting from the salt gradient effect, tumor cell (AsPC-1 and HCT116)-derived exosome translocations could be discriminated from those of HepG2 cell-derived exosomes. The developed highly sensitive detection method for tumor cell-derived exosomes at the single-particle level provides an approach for early cancer diagnosis.

Nanopore Detection of Cancer Biomarkers: A Challenge to Science

Cancer is the most complex and leading cause of fatality worldwide. Despite meritorious research in the field of cancer, it is still a substantial threat to human life. In this article, we address a question on the present strategies and manifest the importance of critical biomarkers for cancer screening and early diagnosis before the symptoms appear. However, this goal can only be achieved if scientists will focus on ultra-sensitive detection techniques such as "Nanopore." Nanopore sensing is a simple and rapid single-molecule detection technique that can detect multiple cancer biomarkers in femto-Molar concentrations in real time. Last but not least, we propose a systematic policy to win the war against cancer that is a big challenge to science.