Abstract

Absolute Quantification of Molecular Biomarkers

Hsueh-Chia Chang, Bayer Professor of Engineering / Director, University of Notre Dame

We report several micro/nanofluidic technologies we invented that can overcome the sensitivity obstacles for liquid biopsy:  (1) A chip electrophoresis module for high-yield exosome extraction without centrifugation;  (2) A Surface Acoustic Wave exosome lysing module that replaces chemical lysing and eliminates the need for low-yield solid/liquid miRNA extraction;  (3) A solid-state  polymer nanopore fM assay that can delay translocation of short 20-nt miRNAs and differentiate the duplexes that have hybridized with inserted oligos and the wild-type miRNAs; (4) A Carbon-Nanotube Protein Sensor with fM sensitivity, three orders of magnitude below KD. Integrated into a biochip, these technologies allow us to quantify protein biomarkers for breast cancer and miRNAs for pancreatic cancer, from patient blood samples, at sensitivities far better than CTC and current molecular biomarker assays, with dramatically improved AUC and p values.  We have eliminated low-yield extraction steps and employed irreversible kinetics to achieve such high performances and have allowed absolute quantification without the need for house-keeping reference molecules.