Synthesis, Characterization and Magnetic Hyperthermia of Monodispersed Cobalt Ferrite Nanoparticles for Cancer Therapeutics.

Magnetic nanoparticles such as cobalt ferrite are investigated under clinical hyperthermia conditions for the treatment of cancer. Cobalt ferrite nanoparticles (CFNPs) synthesized by the thermal decomposition method, using nonionic surfactant Triton-X100, possess hydrophilic polyethylene oxide chains acting as reducing agents for the cobalt and iron precursors. The monodispersed nanoparticles were of 10 nm size, as confirmed by high-resolution transmission electron microscopy (HR-TEM). The X-ray diffraction patterns of CFNPs prove the existence of cubic spinel cobalt ferrites. Cs-corrected scanning transmission electron microscopy-high-angle annular dark-field imaging (STEM-HAADF) of CFNPs confirmed their multi-twinned crystallinity due to the presence of atomic columns and defects in the nanostructure. Magnetic measurements proved that the CFNPs possess reduced remnant magnetization (MR/MS) (0.86), which justifies cubic anisotropy in the system. Microwave-based hyperthermia studies performed at 2.45 GHz under clinical conditions in physiological saline increased the temperature of the CFNP samples due to the transformation of radiation energy to heat. The specific absorption rate of CFNPs in physiological saline was 68.28 W/g. Furthermore, when triple-negative breast cancer cells (TNBC) in the presence of increasing CFNP concentration (5 mg/mL to 40 mg/mL) were exposed to microwaves, the cell cytotoxicity was enhanced compared to CFNPs alone.

Gold-Iron oxide yolk-shell nanoparticles (YSNPs) as magnetic probe for fluorescence-based detection of 3 base mismatch DNA.

Seed-mediated Gold-Iron oxide yolk-shell nanoparticles (YSNPs) were synthesized and functionalized with cy5 attached- thiolated single strand DNA probe for the detection of mutated DNA. The optimum concentration of thiolated DNA determined from a bathochromic shift of surface plasmon resonance (SPR) peak, was 0.177µM. The effect of pH (2-10), temperature (4, 37, 60 and 100 °C), and ionic strengths (1 M to 4 M) on the stability of ssDNA probe tethered YSNPs, studied with the assistance of flocculation parameter. The detection of mutation in DNA was possible using such ssDNA probe functionalized and stabilized nanoparticles. The hybridization of the oligonucleotide probe with the complementary, non-complementary and mutated DNA strands are determined via their respective intensities of the fluorescence of cy5, an efficient fluorescent marker. The intensities help in the comprehension of the specificity of the system. The report predicts controlled efficiency of hybridization with the aid of Hamaker constant, which is determined as 1.15 × 10-20 J for DNA functionalized YSNPs. The minimum concentration of target DNA detected using this methodology was 1.2 × 10-11 mol/L.