Abstract
Tumor-derived circulating exosomes (TDEs) are being pursued as informative and noninvasive biomarkers. However, quantitatively detecting TDEs is still challenging. Herein, we constructed a DNA tetrahedral-structured probe (TSP)-mediated microfluidic magnetic detection system (μFMS) to provide a rapid and sensitive platform for analyzing TDEs. CD63 aptamer-modified Fe3O4 magnetic nanoparticles (MNPs) were constructed to form magnetic nano-report probes (MNRs). The microfluidic chips were fabricated from glass functionalized with DNA TSP-modified aldehyde groups and a PDMS layer designed with serpentine microchannels. An induction coil-based magnetic detector was used to measure the magnetic signal. The linear dynamic range of the μFMS system for TDE assays was 1.98 × 103-1.98 × 107 particles/mL with a limit of detection of 1.98 × 103 particles/mL in PBS. There was no significant difference in TDE detection between the simulated serum and PBS, which indicated the feasibility of the constructed μFMS system for TDE analysis in complex biological systems. In terms of cost, reaction time and operation procedure, this μFMS has the potential to be developed as a clinical point-of-care testing tool for cancer diagnosis and therapeutics.