Aptasensor with Expanded Nucleotide Using DNA Nanotetrahedra for Electrochemical Detection of Cancerous Exosomes

Abstract

Exosomes are extracellular vesicles (50–100 nm) circulating in biofluids as intercellular signal transmitters. Although the potential of cancerous exosomes as tumor biomarkers is promising, sensitive and rapid detection of exosomes remains challenging. Herein, we combined the strengths of advanced aptamer technology, DNA-based nanostructure, and portable electrochemical device to develop a nanotetrahedron (NTH)-assisted aptasensor for direct capture and detection of hepatocellular exosomes. The oriented immobilization of aptamers significantly improved the accessibility of an artificial nucleobase-containing aptamer to suspended exosomes, and the NTH-assisted aptasensor could detect exosomes with 100-fold higher sensitivity when compared to the single-stranded aptamer-functionalized aptasensor. The present study provides a proof-of-concept for sensitive and efficient quantification of tumor-derived exosomes. We thus expect the NTH-assisted electrochemical aptasensor to become a powerful tool for comprehensive exosome studies.

A Sensitive Aptasensor Based on a Hemin/G‐Quadruplex‐Assisted Signal Amplification Strategy for Electrochemical Detection of Gastric Cancer Exosomes

“…Screening of Gastric Cancer Exosome Aptamer : First several reported aptamers were chosen, which were specific to gastric cancer cell or cancer‐related protein as candidates of detection probe. The specificity of aptamer candidates was tested as follows . 10 µL of exosomes was incubated with 10 µL of latex beads for 15 min.…”

“…As exosomes exist in various body fluids and exhibit specific molecular profiles depending on their cell of origin, exosomes have been considered the potential diagnostic biomarkers in cancer. Many methods, including flow cytometry, nanoparticle tracking analysis, enzyme‐linked immunosorbent assay combined with microfluidic platform, and electrochemical biosensors have been developed to achieve the quantification of exosomes (Table S3, Supporting Information) . Aptamers are short ssDNA or RNA molecules which can specifically bind to their targets.…”

Exosomes: Isolation, Analysis, and Applications in Cancer Detection and Therapy

“…Many electrochemically based exosome biosensors have also been developed, because of their simplicity, rapid response, and high sensitivity . The Tan group, for example, developed a sensor for electrochemical detection of cancerous exosomes . In that work, they introduced a aptamer, named LZH8, that could specifically recognize HepG2 (hepatocarcinoma cells) and their exosomes .…”

Intracellular Electrochemical Sensing

“…In the future, other vesicles, including exosomes, could be monitored as they attract a lot of attention . Already, some biosensors for exosomes based on aptamers and for exosomal microRNAs have been reported.…”