Enhanced specific loss power of hematite-chitosan nanohybrid synthesized by hydrothermal method

We used a hydrothermal technique to develop nano-scale α-Fe₂O₃ particles and functionalized them with chitosan. An X-ray diffraction study revealed α-Fe₂O₃ nanoparticles were of single-phase, lattice constants were a = 5.07 Å and c = 13.68 Å, and the grain size was 27 nm. The presence of lattice fringes in the HRTEM image confirmed the crystalline nature of the α-Fe₂O₃. The Mössbauer spectra reveal a mixed relaxation state, which supports the PPMS studies. Zero-field cooled studies revealed the existence of a Morin transition and blocking temperature. The z-average value of the coated particles by DLS was between 218 and 235 nm, PDI ranged from 0.048 to 0.119, and zeta potential was +46.8 mV. We incubated the Vero and HeLa cell lines for 24 h to study the viability of the nanohybrids at different concentrations. Hyperthermia studies revealed the maximum temperature and specific loss power attained by the hematite-chitosan nanohybrid solution of a concentration between 0.25-4 mg ml^-1. The T_max at the lowest and highest concentrations of 0.25 and 4 mg ml^-1 were 42.9 and 48.3°C, while the SLP were 501.6 and 35.5 W g^-1, which are remarkably high when the maximum magnetization of α-Fe₂O₃ nanoparticles was as small as 1.98 emu g^-1 at 300 K.