MicroRNA Extraction from Extracellular Vesicles in Body Fluids Using PMMA-based Nanowire Devices

Abstract

MicroRNAs (miRNAs) within extracellular vesicles (EVs) in body fluids may serve as biomarkers for low-invasive early diseases diagnostics. Although isolation of EVs in body fluids is a crucial step for analyzing miRNAs within the EVs, conventional techniques face challenges due to their low isolation efficiency and requirements of large sample volume. In this work, we propose a method for efficient EV isolation and in-situ miRNA extractions using a disposable microfluidic device with ZnO nanowires. The device has a microchannel on a polymer substrate and the ZnO nanowires are embedded inside the microchannel. The device allows for capturing EVs on nanowire surfaces from biological fluids and extracting miRNAs based on chemical lysis of the captured EVs. Two important factors for the efficient capture mechanism are large surface area of the nanowires and electrostatic interactions between the nanowires and EVs. Our demonstrations confirmed the device isolated EVs from 1 mL of cell supernatant and serum more efficiently in comparison to conventional ultracentrifugation and polymeric precipitation methods. Moreover, by using microarray-based detections of miRNAs extracted from the EVs in human serum, the device also presented a larger number of the detected miRNA types than the conventional methods. EV isolation and miRNA extractions using the device may contribute to realize low-invasive early disease diagnosis and new biomarker development.