Integrated Microfluidic System for Cell-Free DNA Extraction from Plasma for Mutant Gene Detection and Quantification

Ovarian cancer (OvCa) is among the most severe gynecologic cancers, yet individuals may be asymptomatic during its early stages. Routine, early screening for genetic abnormalities associated with OvCa could improve prognoses, and this can be achieved by detecting mutant genes in cell-free DNA (cfDNA). Herein, we developed an integrated microfluidic chip (IMC) that could extract cfDNA from plasma and automatically detect and quantify mutations in the OvCa biomarker BRCA1. The cfDNA extraction module relied on a vortex-type micromixer to mix cfDNA with magnetic beads surface-coated with cfDNA probes and could isolate 76% of molecules from a 200 μL plasma sample in 45 min. The cfDNA quantification module, which comprised a micropump that evenly distributed 4.5 μL of purified cfDNA into the on-chip, allele-specific quantitative polymerase chain reaction (qPCR) zones, was capable of quantifying mutant genes within 90 min. By automating the cfDNA extraction and qPCR processes, this IMC could be used for clinical screening for OvCa-associated mutations.