Chitosan- or Poly-L-lysine-modified nanoparticles for nucleic acid separation

The separation and detection of nucleic acids (NAs) from clinical samples play crucial roles in biomedical sciences. Surface modified magnetic nanoparticles with various reactive groups can efficiently adsorb nucleic acids. This article demonstrates the modification of silica-coated magnetic nanoparticles (SiO 2 @MNPs) by chitosan (Chit) and poly- l -lysine (PLL) for efficient separation of nucleic acids. The physico-chemical properties (like size, shape, zeta potential, isoelectric point, and magnetic properties) of Chit-SiO 2 @MNPs and PLL-SiO 2 @MNPs were characterized to identify optimized conditions for chitosan and poly- l -lysine adsorption on the SiO 2 @MNPs surface. The optimal w/w ratio for Chit/SiO 2 @MNPs and PLL/SiO 2 @MNPs was found to be 0.5 and 0.05, respectively. Hereafter, the samples are designated as Chit-SiO 2 @MNPs-opt and PLL-SiO 2 @MNPs-opt. The biological activity results confirm that Chit-SiO 2 @MNPs-opt and PLL-SiO 2 @MNPs-opt bind to single-stranded RNA and extract 58.64% and 33.99% of RNA, respectively, improving RNA isolation performance compared to SiO 2 @MNPs (3.86%). The obtained efficiency of RNA extraction makes chitosan and poly- l -lysine modified magnetic nanoparticles promising candidates for clinical applications related to the separation of RNA viruses.