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This work demonstrates a new class of magnetic resonance (MR) active aqueous Fe 3 O 4 magnetic nanoparticle nanoassemblies (Fe 3 O 4 MNNA) of $40 nm size comprising $6 nm particles. They exhibit enhancement in T 2 MR contrast as compared to 6 nm isolated counterparts (Fe 3 O 4 MNP) and commercial contrast agent, ferumoxytol. This significant improvement in the T 2 MR signal arises from the synergistic magnetism of multiple Fe 3 O 4 nanoparticles assembled in Fe 3 O 4 MNNA. These nanoassemblies also show better colloidal stability, higher magnetization, good specific absorption rate (under external AC magnetic field) and cytocompatibility with cells. Further, the functional groups (-NH 2 ) present on the surface of Fe 3 O 4 particles can be accessible for routine conjugation of biomolecules through well-developed bioconjugation chemistry. Specifically, a new MR active colloidal amine-functionalized Fe 3 O 4 nanoassembly with enhanced T 2 contrast properties has been fabricated, which can also be used as an effective heating source for hyperthermia treatment of cancer.

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We report a facile soft-chemical approach for the fabrication of Fe 3 O 4 embedded ZnO magnetic semiconductor nanocomposites (Fe 3 O 4 -ZnO MSN), and investigate and compare their efficacy for the detoxification of water with respect to their individual counterparts (Fe 3 O 4 and ZnO). The formation of Fe 3 O 4 -ZnO MSN was evident from the detailed structural analyses by XRD, TEM and magnetic measurements. It has been observed that these nanocomposites have a strong tendency for the simultaneous removal of Ni 2+ , Cd 2+ , Co 2+ , Cu 2+ , Pb 2+ , Hg 2+ and As 3+ from waste-water due to their porous network structure, surface polarity and high surface area. These nanocomposites also show a good photocatalytic activity for the degradation of organic dyes under UV irradiation, and are found to be efficient in the easy and rapid capturing of bacterial pathogen. It has been observed that the efficiency of capturing bacteria is strongly dependent on the concentration of nanoadsorbents and their inoculation time. It is investigated that these nanoadsorbents can be used as highly efficient separable and reusable materials for the simultaneous removal of toxic metal ions, organic dyes and bacterial pathogen.

The design and development of water dispersible, pH responsive peptide mimic shell cross‐linked magnetic nanocarriers (PMNCs) using a facile soft‐chemical approach is reported. These nanocarriers have an average size about 10 nm, are resistant to protein adsorption in physiological medium, and transform from a negatively charged to a positively charged form in the acidic environment. The terminal amino acid on the shell of the magnetic nanocarriers allows us to create functionalized exteriors with high densities of organic moieties (both amine and carboxyl) for conjugation of drug molecules. The drug‐loading efficiency of the nanocarriers is investigated using doxorubicin hydrochloride (DOX) as a model drug to evaluate their potential as a carrier system. Results show high loading affinity of nanocarriers for anticancer drug, their sustained release profile, magnetic‐field‐induced heating, and substantial cellular internalization. Moreover, the enhanced toxicity to tumor cells by DOX‐loaded PMNCs (DOX‐PMNCs) under an AC magntic field suggest their potential for combination therapy involving hyperthermia and chemotherapy.

La(0.7)Sr(0.3)MnO(3) (LSMO) nanoparticles have been prepared using glycine and polyvinyl alcohol (PVA) as fuels. Their crystal structure, particle morphology and compositions are characterized using X-ray diffraction, transmission electron microscopy, field-emission electron microscopy and energy dispersive analysis of X-ray. They show a pseudo-cubic perovskite structure. The spherical particle sizes of 30 and 20 nm have been obtained from samples prepared by glycine and PVA respectively. The field cooled (FC) and zero field cooled (ZFC) magnetizations have been recorded from 5 to 375 K at 500 Oe and superparamagnetic blocking temperatures (T(B)) of 75 and 30 K are obtained from samples prepared by glycine and PVA respectively. Particle size distribution is observed from dynamic light scattering measurements. Dispersion stability of the particles in water is studied by measuring the Zeta potential with varying the pH of the medium from 1 to 12. Under induction heating experiments, a hyperthermia temperature (42-43 °C) is achieved by both the samples (3-6 mg mL(-1)) at magnetic fields of 167-335 Oe and at a frequency of 267 kHz. The bio-compatibility of the LSMO nanoparticles is studied on the L929 and HeLa cell lines by MTT assay for up to 48 h. The present work reveals the importance of synthesis technique and fuel choice on structural, morphological, magnetic, hyperthermia and biocompatible properties of LSMO and predicts the suitability for biomedical applications.

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