Biocompatibility studies of functionalized cofe<inf>2</inf>o<inf>4</inf> magnetic nanoparticles

CoFe2O4 nanoparticles of different sizes were synthesised by controlling the digestion time using precipitation method and were characterised by X-ray diffraction, transmission electron microscopy, dynamic light scattering, and vibrating sample magnetometer. The average crystalline size increases from 13.9 to 19 nm as the digestion time is increased from 1.3 to 120 minutes. The CoFe2O4 nanoparticles were coated with two biological polymers, namely polyvinyl alcohol (PVA) and polyethylene glycol (PEG) at various ra- tios to enhance their biocompatibility. Coated nanoparticles were analysed for their cytotoxicity by MTT assay against 3T3-L1 adipo- cytes. Coated nanoparticles were found to be less cytotoxic when compared to uncoated one. The cell viability decreased as the concen- tration of the polymer (either PVA or PEG) coating increased. Cell viability decreases as the concentration of nanoparticle increases. At 5 g/ml the cell viability with PEG coated nanoparticles (1:4) was 92.5%, with PVA coated nanoparticles (1:4) was 82.7% and with un- coated nanoparticles it was 46.4%. As the ratio of biopolymers (PVA and PEG) to nanoparticle increases, the viability of the cell in- creases. The difference between the effect of these two polymers increases as the concentration of the nanoparticle decreases. The anti- inflammatory properties of these nanoparticles were determined by RTPCR by measuring the two pro-inflammatory cytokines (namely tumor necrosis factor and IL6). TNF- and IL6 were upregulated by 3.57- & 2.86 folds their base level with uncoated nanoparticles. Whereas it was upregulated by 1.54- & 1.68-folds with PEG coated and 1.9- & 2.18-folds with PVA coated nanoparticles. Thus the coated nanoparticles can be used for further biological experiments including magnetic resonance imaging, and in targeted drug delivery systems for various diseases. © 2011 Bentham Science Publishers Ltd.