The role of Zn2+ on structure, magnetic properties, and drug delivery performance of ZnxFe3–xO4/SiO2 nanocomposites

A series of Zn x Fe 3– x O 4 /SiO 2 nanocomposites ( x = 0, 0.1, and 0.9) for drug delivery applications has been successfully prepared using coprecipitation and sol–gel methods. X-ray diffraction analysis showed a shift in the Zn x Fe 3– x O 4 peaks to lower 2 θ due to the role of incorporating Zn 2+ , associated with increasing lattice parameters from 8.377 Å to 8.388 Å in the spinel structure. In addition, a broad peak appeared at 2θ ≈ 22 o –24 o , originating from amorphous SiO 2 . The metal–oxygen bonds (Zn–O and Fe–O) were detected at octahedral (526–535 cm –1 ) and octahedral (409–480 cm –1 ) sites. The symmetric and asymmetric vibrations of Si–O–Si were detected at 805–941 cm –1 and 1067–1094 cm –1 , respectively. The stretching vibrations of Fe–O–Si were detected at 544–580 cm –1 , indicating a chemical interaction between Zn x Fe 3– x O 4 and the SiO 2 network. The Zn x Fe 3– x O 4 /SiO 2 nanocomposites had a spherical morphology and a particle size of approximately 36.99–41.79 nm. The nanocomposites displayed an S -like pattern, indicating superparamagnetic characteristics. The saturation magnetization exhibited a non-linear trend over the range 1.64–4.21 emu/g, attributed to Zn 2+ substitution in the crystal lattice and particle size. The drug carrier performance of the nanocomposites was achieved for x = 0.1 with loading (above 95%) and release (above 64%). Doxorubicin molecules were considered to be adsorbed onto Zn x Fe 3– x O 4 /SiO 2 nanocomposites through electrostatic interactions, hydrogen bonding, and π–π interactions. Therefore, the Zn x Fe 3– x O 4 /SiO 2 nanocomposites show great promise as drug delivery agents for inhibiting cancer cell proliferation.