Highly sensitive detection of extracellular vesicles on ZnO nanorods integrated microarray chips

Extracellular vesicle (EV) has become a type of potential biomarker for cancer diagnosis in liquid biopsy. However, the accurate detection of EVs for large-scale cancer scanning is still challenge due to the low sensitivity, high cost, and requirement of large instruments, which impedes their wide applications in clinical trials, especially in resource limited areas. Researchers at the Huazhong University of Science and Technology report a ZnO nanorods integrated microarray chip (ZnO-chip) for effective capture and sensitive detection of EVs. The ZnO-chip provides abundant binding sites for EVs capture. Meanwhile, the high-ordered hybridization chain reaction and non-ordered enzyme catalytic reaction are collaborated for cascade signal amplification. The oxidized product, glucose, can be read out directly by portable glucometer to realize accurate quantitation of EVs with a linear range of 1.0 × 10⁴ to 8.4 × 10⁷ particles/μL and a minimal detectable concentration of 3.3 × 10³ particles/μL. This approach could distinguish cancer patients from healthy individuals, proving the statistically increase of EVs in serums of cancer patients. Finally, the researchers verify that the captured EVs can be released for downstream molecular assays by dissolving ZnO nanorods under slightly acidic condition. They believe their approach has remarkable possibility for the routine screening of cancer patients in clinical trials.