γ-Fe2O3@SiO2 core-shell structured nanoparticle: Fabrication via surface treatment and application for plasmid DNA purification

• Published in: Ceramics international 2017-10, Vol.43 (15), p.12888-12892
• Main Authors: An, Gye Seok, Choi, Soo Wan, Chae, Dong Ho, Lee, Hyeon Seung, Kim, Hyeong-Jun, Kim, YooJin, Jung, Yeon-Gil, Choi, Sung-Churl
• Format: Article
• Language: English
• Subjects: Core-shell structure; Maghemite; Plasmid DNA purification; Surface treatment; Zeta potential
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2017.06.183

Plasmid DNA was purified using core-shell γ-Fe2O3@SiO2 nanoparticles synthesized by a common sol-gel method utilizing tetraethylorthosilicate (TEOS) as a silica precursor. The dispersibility and TEOS binding affinity of γ-Fe2O3 nanoparticles were enhanced by acid/base treatment due to the formation of additional surface hydroxyl groups prior to SiO2 deposition. Since SiO2 was coated under basic conditions in the presence of ammonia as a catalyst, base-treated γ-Fe2O3 nanoparticles were more suited for this modification due to exhibiting a larger zeta potential and a lower saturation magnetization loss. The performance of the synthesized γ-Fe2O3@SiO2 nanoparticles with a 15-nm-thick SiO2 layer in the purification of plasmid DNA was compared to that of commercial Fe3O4-based magnetic beads. The used DNA samples exhibited similar purities, and all samples had similar theoretical plasmid DNA binding capacities. However, γ-Fe2O3@SiO2 nanoparticles exhibited a faster separation speed and a larger saturation magnetization of 100emu/g compared to that of commercial Fe3O4-based magnetic beads (75emu/g).