Rapid and Efficient Extraction of Cell-Free DNA Using Homobifunctional Crosslinkers

Since its discovery in circulating blood seven decades ago, cell-free DNA (cfDNA) has become a highly focused subject in cancer management using liquid biopsy. Despite its clinical utility, the extraction of cfDNA from blood has many technical difficulties, including a low efficiency of recovery and long processing times. We introduced a magnetic bead-based cfDNA extraction method using homobifunctional crosslinkers, including dimethyl suberimidate dihydrochloride (DMS). Owing to its bifunctional nature, DMS can bind to DNA through either covalent or electrostatic bonding. By adopting amine-conjugated magnetic beads, DMS–DNA complexes can be rapidly isolated from blood plasma. Using standard washing and eluting processes, we successfully extracted cfDNA from plasma within 10 min. This method yielded a 56% higher extraction efficiency than that of a commercial product (QIAamp kit). Furthermore, the instant binding mechanism of amine coupling between the microbeads and DMS–DNA complexes significantly reduced the processing time. These results highlight the potential of this magnetic bead-based homobifunctional crosslinker platform for extraction of cfDNA from blood plasma.