Characterization of Extracellular Vesicles by Resistive-Pulse Sensing on In-Plane Nanofluidic Devices

In the past twenty years, research related to characterizing extracellular vesicles (EVs) has increased at a rapid rate, largely due to their influence in biological systems and potential impact in drug discovery. EVs are naturally produced, membrane-bound, nanoscale particles that are linked to cell-cell communication and propagation of diseases. The cargo carried by EVs mimics that of the parent cells from which they were derived and can be diagnostic of parent cells themselves. Conventional characterization techniques for EVs include dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and charge detection mass spectrometry (CDMS). To make similar measurements in solution, we are developing resistive-pulse sensing devices with multiple pores in series, which are fabricated in-plane on glass substrates by focused ion beam (FIB) milling. Because resistive-pulse sensing characterizes individual particles, we can easily correlate their size and pore-to-pore times, unlike DLS and NTA, which provide distributions for entire populations. Precision of the resistive-pulse sensing is further improved by passing the particles through multiple pores in series. In this presentation, we will discuss fabrication and characterization of the nanofluidic devices and their application to the measurement of EVs from various sources, including bovine milk, human urine, and plants. In the longer term, resistive-pulse measurements of exosomes derived from human samples may indicate disease states when patient samples are compared to control samples.