Effect of spin and orbital selectivity of DNA induced SiO2 coated Fe3O4 nanoparticles: X-ray magnetic circular dichroism study

UNPAD & Global Partners Reveal How DNA Boosts Surface Magnetism in Silica-Coated Magnetite—Unlocking Faster Bioseparation (SDG 3 & SDG 9)
A collaborative team (India, Singapore/A*STAR, Universitas Padjadjaran, Japan/KEK-PF) shows that when DNA adsorbs onto SiO₂-coated Fe₃O₄ nanoparticles, the element-specific magnetization increases—clarified using soft X-ray XAS/XMCD. Structurally, the particles retain single-phase inverse-spinel Fe₃O₄ with an amorphous SiO₂ (and DNA) shell confirmed by XRD, TEM/SAED, STEM-EDX.
Spectroscopy reveals a shift of the Fe L₃ edge toward Fe²⁺ character after DNA adsorption and pre-edge O-K features (A₁≈530.2 eV, A₂≈532.0 eV) consistent with interfacial charge transfer at the Fe–O–Si–PO₄ network. Sum-rule analysis shows the total magnetic moment rises with DNA, with ΔM up to ~0.95 μB/Fe across thicker SiO₂/DNA cases—evidence of spin selectivity favoring Fe²⁺ that can simplify magnetic DNA separation.

Discover more: https://doi.org/10.1016/j.colsurfa.2025.136111