Abstract

Dielectrophoresis Based Collection of Extra Cellular Vesicles and On Chip Analysis of Nucleic Acid Payload

Stuart Ibsen, Assistant Professor, The Knight Cancer Institute’s Cancer Early Detection Advanced Research Center (CEDAR), Oregon Health and Science University

Differentiating patients with pancreatic cancer (PDAC) from patients with precancerous intraductal papillary mucinous neoplasms (IPMN) and pancreatitis is a challenge using traditional blood-based biomarkers like CA 19-9. Extracellular vesicle (EV) nanoparticles are a valuable source of cancer-derived biomarkers that are released by tumors into circulation throughout their development. These particles include extracellular vesicles, organelle fragments, and cell free DNA (cf-DNA) nanoparticles. However, it is a challenge to use these nanoparticles for clinical diagnostic applications due the difficulty of recovering them from plasma for analysis. We address this challenge through the use of high conductance dielectrophoresis (DEP) to simultaneously recover different nanoparticle types from a single undiluted plasma sample in a quick and easy microfluidic chip format. This method takes advantage of the difference in the dielectric properties between the nanoparticles and the surrounding plasma to create a force that pulls nanoparticles down to an electrode array. The particles are held with enough force to remove the bulk plasma using a fluidic wash. This can simultaneously collect both EVs and cf-DNA nanoparticles around the edges of the electrodes used to generate the DEP force. The combination of EV biomarkers (Glypican-1) and the level of cf-DNA nanoparticles can be used to successfully differentiate PDAC patients from patients with benign pancreatic diseases using a blinded cohort study design. This can also differentiate between PDAC patients and patients with IPMN making this study among the first that we are aware of developing a multiomic threshold that can distinguish between PDAC and IPMN lesions. This is clinically important because IPMNs are a major source of false positives for multiomic biology-based screening. This multiomic biomarker panel had a sensitivity of 0.92, a specificity of 0.88, and an AUC of 0.80 in differentiating between PDAC and benign pancreatic diseases, which is comparable to the traditional invasive endoscopic ultrasound-guided fine needle aspiration (EUS/FNA) diagnostic procedure (AUC 0.79). This new dielectrophoresis-based technique shows multiple types of cancer-derived nanoparticles can be quickly and easily recovered from a single plasma sample and that their associated biomarkers are promising for future use in clinical diagnostics.