A homogeneous electrochemical sensing platform based on DNAzyme walker for accurate detection of breast cancer exosomes

Abstract

Exosomes generated from tumors contain a range of bioactive molecules, making them attractive and trustworthy non-invasive biomarkers for prognostic monitoring and adjuvant diagnosis of malignancies. Here, a homogeneous portable electrochemical sensing platform based on DNAzyme-induced DNA walker and enzyme-catalyzed amplification strategies has been created to accurately identify exosomes from breast cancer. The aptasensor induced enzymatic cleavage through dual probe recognition, and the continuous movement of the DNA walker achieves the cleavage of a large number of substrate strands. This causes a significant number of enzyme-containing DNA fragments to be released, and the enzyme that is released catalyzes the production of hydrogen peroxide (H2O2) by oxidizing excess glucose. The hydrogen peroxide (H2O2) underwent a redox reaction using a screen-printed carbon electrode (SPCE), and the detection of exosome can be achieved by reading current signal changes. The detection limit of the sensor is 3.63 × 104 particles/mL SK-BR-3 exosomes. This method improved the accuracy of detection by double recognition of MUC1 protein and HER2 protein on breast cancer exosomes and avoided cumbersome electrode modification steps. In addition, clinical serum samples can be analyzed using the constructed electrochemical sensor to separate patients with breast cancer from healthy volunteers as well as patients with various tumors. It is anticipated that the current work will give an effective tool for the accurate detection of breast cancer exosomes because it presents a novel technique for doing so in HER2-positive breast cancer.