A Dual Metal–Organic Framework-Based Electrochemical Biosensor for the Capture and Detection of Cancerous Exosomes

Abstract

Exosomes are emerging cancerous biomarkers, while reliable, convenient, and highly sensitive analysis remains challenging. Herein, we report a dual metal–organic framework (MOF)-based electrochemical biosensor for directly capturing and detecting cancerous exosomes in complex biological samples. This biosensor comprises three key components, that is, a pH-sensitive ZIF-8-engineered screen-printed carbon electrode for signal transduction, a pH-insensitive magnetic nanoparticle-modified copper-based MOF (MNP/Cu-BTC MOF) for exosome collection, and a DNA logic system for DNA computation. MNP/Cu-BTC MOF can directly and rapidly collect exosomes from biological media without the use of expensive antibodies or time-consuming centrifugation processes. By introduction of a DNA-based logic system, streptavidin-glucose oxidase (SA-GOx) can be chemically bonded to the surface of exosomes through the biotin–streptavidin interaction. This fabricated biosensor allows ultrasensitive detection of exosomes through the combination of magnetic enrichment, acidification of the solution around the electrode through enzymatic catalysis of glucose to gluconic acid, and ZIF-8-mediated signal transduction as an exosome capture tool. The fabricated biosensor allows label-free detection of exosomes ranging from 104 to 108 particles mL–1 with a limit of detection of 2.2 × 104 particles mL–1. With its capacity for simple exosome collection, accurate identification, and sensitive detection, the proposed biosensor may accelerate the translation of exosome analysis for routine clinical testing.

A lateral flow assay strip for simultaneous detection of miRNA and exosomes in liver cancer

“…However, ELISA procedures are complex and time-consuming. 8 Although some emerging strategies with high potency have been developed to detect exosomes by analysing specific surface proteins, such as colorimetric, 9,10 electrochemical 11,12 and fluorescence, 13–15 most of them involve tedious steps and focus on a single biomarker, which may limit their accuracy in cancer diagnosis. To increase the portability and specificity of disease detection, it is preferable to develop simple and robust methods for multiplexed biomarker detection.…”