Exosomes， closely associated with tumor development and metastasis， carry biomolecules （proteins， nucleic acids， etc.） that serve as diagnostic “fingerprints” for tumors， which are favored by researchers as key biomarkers. Therefore， developing convenient， rapid， sensitive， and reliable methods for detecting exosome is of paramount importance. As superior recognition elements compared to antibodies， aptamers can identify specific biomolecules or signaling markers on exosomes. Aptamer electrochemical sensors， combining the advantages of aptamers and electrochemical methods， represent a more competitive tool for applications such as liquid biopsy and early cancer screening. They are particularly well-suited for rapid point-of-care testing and the detection of exosomes in complex matrix samples. In this paper， the detection modes and application scope， along with various signal amplification strategies of aptamer electrochemical sensors for exosome over the past five years were reviewed. This paper also outlines the future trends for these sensors in the field of exosomes detection.

Contents

1 Introduction

2 Aptamer and aptamer electrochemical sensor

2.1 Definition and characteristics of aptamer

2.2 Engineering strategies of aptamer-modified interfaces

2.3 Structure and detection principle of aptamer electrochemical sensors

3 Mode of aptamer electrochemical sensors for detecting exosome

3.1 Direct detection

3.2 Sandwich-type

3.3 Logic gate

4 Signal amplification modes for aptamer electrochemical sensors in detecting exosome

4.1 Signal amplification in DNA walker

4.2 CRISPR-Cas system mediated signal amplification

4.3 Signal amplification in proximity ligation strategy

4.4 Signal amplification in isothermal nucleic acid amplification technology

5 Conclusion and outlook