Figure 2.

Operation principles of a cfNA isolation based microfluidic system with DTBP. 1) Chip preparation: assembling the microfluidic platform and inner surface modification with APDMS for binding the amine group of DTBP. 2) Sample mixing: blood plasma samples were mixed with DTBP solution (30 mg mL⁻¹) and injected into the platform. 3) Binding: DTBP binds to the amine group of both APDMS and nucleic acids by covalent bonding and electrostatic coupling. 4) Washing and elution: after washing with PBS, elution buffer leads to the breakage of the cross‐linking, thus eluting cfDNA (or cfRNA).