Nature-Inspired Histidine and Guanidine Modification of Magnetic Nanoparticles for Urinary DNA Liquid Biopsy

Urinary cell-free DNA (cfDNA) is a promising substrate for non-invasive liquid biopsy analysis and biomarker detection. However, the lack of standardized pre-analytical workflows and the intrinsic challenges associated with isolating highly dilute and fragmented cfDNA limit its broader research and clinical applications. Here, we present a simplified, reliable and cost-effective extraction platform based on iron oxide nanoparticles (IONPs) synthesized via coprecipitation. By leveraging nature-inspired surface functionalization, these magnetic nanoparticles enable the rapid and direct isolation of cfDNA from fresh urine while supporting scale-up of the processing volumes. The proposed platform achieves a 2-fold increase in cfDNA yield compared to conventional commercial extraction kits and demonstrates enhanced recovery of short DNA fragments, with a predominant size distribution between 80-150 bp. This improved capture efficiency facilitates a detection sensitivity down to 10^-3 ng/mL using qPCR, likely limited by assay sensitivity rather than DNA extraction performance. Moreover, the simplified extraction and elution steps eliminate the need for specialized laboratory instrumentation. Collectively, this approach provides a foundation for accessible, potentially at-home cfDNA extraction and advances the development of truly non-invasive diagnostic strategies for longitudinal disease monitoring and management.