FERRIMAGNETIC ZNFE2O4 NANOPARTICLES IN BIOACTIVE GLASS CERAMICS
FOR THE HYPERTHERMIA TREATMENT OF CANCER
M. U. Hashmi, Saqlain A. Shah
Department of Applied Sciences, Superior University Lahore, Pakistan
Ferrimagnetic bioactive Nanoparticles are expected to be potential candidates for the hyperthermia
treatment of cancer. When placed under an alternating magnetic field of high frequency, these particles generate
heat energy by hysteresis losses. Tumor cells usually perish around 43 °C due to the poorly developed nervous and
circulatory system whereas healthy body cells remain unaffected at this temperature. Such materials should have
the adequate ability to bond with the tissues (bioactivity). Much work has been done on Fe3O4 nanoparticles in
glass ceramics for this purpose but present work is the first ever detailed study of its kind on ferrimagnetic
ZnFe2O4 nanoparticles in bioactive glass ceramics for the hyperthermia treatment of cancer.
Glass ceramics of the composition xZnO • 25Fe2O3 • (40 -x)SiO2 • 25CaO • 7P2O5 • 3Na2O were prepared by
the melt-quench method. Glass-powder compacts were sintered at 1100 ºC for 3h and then rapidly cooled at -10
ºC. Vibrating sample magnetometer (VSM) data at 10 kOe showed that saturation magnetization, coercivity and
hence hysteresis area increased with the increase in ZnO content. ZnFe2O4 nanoparticles exhibited ferrimagnetism
due to the random distribution of Zn2+ and Fe3+ cations at tetrahedral A sites and octahedral B sites. This
inversion/random distribution of cations was probably due to the surface effects of nanostructures of ZnFe2O4 and
rapid cooling of the material from 1100 ºC (thus preserving the high temperature state of the random distribution
of cations). Calorimetric measurements were carried out using magnetic induction furnace at 500 Oe magnetic
field and 400 kHz frequency. The data showed that maximum specific power loss and temperature increase after 2
min were 26 W/g and 37 ºC, respectively for the sample containing 10% ZnO. The glass ceramic samples were now heated to 600 °C and cooled in an aligning magnetic field of 1 Tesla
to cause anisotropy. Magnetically aligned samples were compared with the non-aligned samples. VSM
measurements at 10 kOe showed that the magnetic properties were enhanced by the aligning magnetic field and it
led to enhance the magnetic heat generation under magnetic induction furnace operating at 500 Oe and 400 kHz
for 2 min. Data showed that maximum specific power loss and temperature increase after 2 min were 31.5 W/g and
45 °C respectively for the aligned sample containing 10% ZnO.
The samples were immersed in simulated body fluid (SBF) for 3 weeks. Scanning electron microscope
(SEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and XRD results
confirmed the growth of precipitated hydroxyapatite phase after immersion in SBF, suggesting that the
ferrimagnetic glass ceramics were bioactive and could bond to the living tissues in physiological environment.
Thus, following are the prime features of this research work:
1. Generally, Fe3O4 (magnetite) nanoparticles have been used in this research arena of biomaterials. Present
work is the first ever detailed study of its kind on ferrimagnetic ZnFe2O4 containing bioactive glass
2. ZnFe2O4 is a paramagnetic substance at room temperature. In this work it is made ferrimagnetic by special
treatment of quenching the substance after sintering.
3. The magnetic and heat generating properties of the ferrimagnetic zinc-ferrite containing bioactive glass
ceramics have been enhanced by cooling the substance in aligning magnetic field, without any
compositional or micro-structural changes in the material.
4. The glass ceramics presented in this work possess not only sufficient magnetic and calorimetric properties
but also adequate bioactivity, making it a potential candidate for the hyperthermia treatment of cancer as
well as for the re-generation of damaged bone.