Purpose <p>The main objective of this research is to prepare and characterize silica-coated magnetic capsules and investigate them for DNA extraction via adsorption and desorption process as a function of pH and DNA concentration.</p> Method <p>A novel approach was used to synthesize and emulsify ferrofluid, followed by silica coating of the resulting nanoparticles using sol-gel process consuming TEOS and APTES as silica precursors separately. TEM, XRD, DLS, FTIR, and TGA are employed to determine the size distribution, crystallinity, morphology, and chemical composition of the nanoparticles.</p> Results <p>The ferrofluid contains magnetic nanoparticles stabilized with oleic acid in octane. O/W (oil-in-water) magnetic emulsion and silica-coated capsules have an average size of 280, 290, and 320&#xa0;nm, respectively. The successful extraction of DNA using these capsules is evidenced by the quantification of immobilized DNA on the particles.</p> Conclusions <p>This research work shows positive results regarding DNA immobilization and separation methodologies, suggesting potential avenues for practical biomedical applications.</p> Graphical Abstract <p></p>