Work

Silica coating of thermal decomposition-based hydrophilic and hydrophobic magnetic nanoparticles for nucleic acid extraction

Year: 2025

Type: article

Abstract: Superparamagnetic iron oxide nanoparticles (IONPs) hold diverse utility in biomedicine, particularly in sample enrichment and sensing applications for disease detection. The synthesis and surface functionalization of IONPs are crucial steps therein, demanding technical attention. Most surface functionalization investigations have focussed on IONPs synthesized using the co-precipitation approach. However, the full potential of the thermal decomposition method, which yields high-quality solvent-dispersible IONPs with a narrow size distribution, has not been utilized for silica coating to produce IONPs with varying morphologies, silica shell thicknesses and magnetic properties for their use in nucleic acid extraction. Hence, our current work investigates the silica coating of hydrophilic as well as hydrophobic IONPs synthesized via the thermal decomposition method. Hydrophilic and hydrophobic IONPs were coated with silica using varying amounts of precursor to create amine-functionalized IONPs with a thinner silica shell and the highest magnetization saturation value. In addition to this, the relationship between colloidal stability and the silica coating process was made apparent by the functionalization of phase-transferred IONPs at two distinct pH values. Ultimately, the successfully silica-coated IONPs from hydrophilic and hydrophobic (phase-transferred) synthesis modes were used for nucleic acid extraction, whereas the non-silica-coated phase-transferred IONPs were not tested for the same application. All the silica-coated IONPs independently demonstrated their nucleic acid extraction capability from INF-A and SARS-CoV-2, validated using RT-PCR. The capture efficiency of each of these IONPs can be further increased by adjusting and refining the reaction conditions utilized for nucleic acid extraction and subsequent applications in diagnostics and therapy.

Source: Colloids and Surfaces A Physicochemical and Engineering Aspects

DOI: 10.1016/j.colsurfa.2025.137663