Two-in-one sensing platform for the detection of exosomes based on molybdenum disulfide-based nanozymes

Compared with single-mode detection strategies, multi-mode sensing strategies have attracted more and more scientists' attention due to their higher detection accuracy and credibility. Herein, a two-in-one sensing platform was designed for human breast cancer cell line (MCF-7)-derived exosomes detection by coupling the high catalytic activity of gold-platinum core-shell nanoparticles-decorated molybdenum disulfide nanozymes (MoS2-Au@Pt) with the specific recognition ability of aptamers (Apt). Probe DNA1 (P1) was assembled on the surface of MoS2-Au@Pt nanozymes to form MoS2-based signal amplified nanoprobes (MNP), which can efficiently catalyze 3, 3′, 5, 5′-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) reaction strategy to produce distinct electrochemical and colorimetric responses. The added target exosomes triggered the dissociation of the "probe DNA2-Apt-MNP" sandwiched structure and the release of MNP from the electrode surface due to the preferential reaction of anti-CD63 aptamer and exosomes, leading to both electrochemical signal and solution color were reduced. According to this interesting sensing principle, the developed electrochemical/colorimetric dual-mode aptasensor showed excellent sensitivity and specificity for exosomes analysis with low detection limits of 9.3 particles mL−1 (electrochemical) and 4.2 × 103 particles mL−1 (colorimetric), respectively. Furthermore, this dual-mode aptasensor can determine exosomes in human serum with high recoveries (>93 %) and low relative standard deviation (RSD, <8 %), suggesting that the developed dual-mode detection strategy is a promising sensing method for accurate, sensitive and selective analysis of biomarkers in clinical samples.