Previous attempts to review the literature on magnetic nanomaterials for hyperthermia-based therapy focused primarily on magnetic fluid hyperthermia (MFH) using mono metallic/metal oxide nanoparticles. The term “Hyperthermia” in the literature was also confined only to include use of heat for therapeutic applications. Recently, there have been a number of publications demonstrating magnetic nanoparticle-based hyperthermia to generate local heat resulting in the release of drugs either bound to the magnetic nanoparticle or encapsulated within polymeric matrices. In this review article, we present a case for broadening the meaning of the term “hyperthermia” by including thermotherapy as well as magnetically modulated controlled drug delivery. We provide a classification for controlled drug delivery using hyperthermia: Hyperthermia-based controlled Drug delivery through Bond Breaking (DBB) and Hyperthermia-based controlled Drug delivery through Enhanced Permeability (DEP). The review also covers, for the first time, core-shell type magnetic nanomaterials, especially nanoshells prepared using layer-by-layer self-assembly, for the application of hyperthermia-based therapy and controlled drug delivery. The highlight of the review article is to portray potential opportunities in the combination of hyperthermia-based therapy and controlled drug release paradigms for successful application in personalized medicine.

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Gold nanoshell around super paramagnetic iron oxide nanoparticles (SPIONs) was synthesized and small angle X-ray scattering (SAXS) analysis suggests a gold coating of approximately 0.4 to 0.5 nm thickness. On application of low frequency oscillating magnetic fields (44 – 430 Hz), a four- to five-fold increase in the amount of heat released with gold-coated SPIONs (6.3 nm size) in comparison with SPIONs (5.4 nm size) was observed. Details of the influence of frequencies of oscillating magnetic field, concentration and solvent on heat generation are presented. We also show that, in the absence of oscillating magnetic field, both SPIONs and SPIONs@Au are not particularly cytotoxic to mammalian cells (MCF-7 breast carcinoma cells and H9c2 cardiomyoblasts) in culture, as indicated by the reduction of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium by viable cells in a phenazine methosulfate-assisted reaction.

The mesoporous silica nanoparticles (MSNs), because of the synthesis, ease of surface functionalization, tunable pore size, large surface area, and biocompatibility, are being useful in many of the biomedical applications like drug delivery, theranostics, stem cell research, etc. It has been a potent nanocarrier for many different therapeutic agents, i.e., the surface functionalization of silica nanoparticles (SNs) with chemical agents, polymers, and supramolecular moieties enable the efficient delivery of therapeutic agents in a highly controlled manner. Also, the toxicity, biosafety, and in vivo efficiency involving biodistribution, pharmacokinetics, biodegradation, and excretion of MSNs play an important role in its involvement in the clinical applications. A coherence between chemistry and biological sciences extends its opportunities to a wide range in the field of nanomedicine such as smart drug delivery systems, functionalization and gating approach, controlled drug delivery systems, diagnostic and targeted theragnostic approach etc. Thus, taking advantage of the inbuilt properties of the MSNs applicable to the biomedical sector, the present review describes a panorama on the SNs which are presently used for the development of theragnostic probes and advanced drug delivery platforms.

A facile synthesis of carbon nanotube hybrid nanostructures: energy and environmental applications.

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We report step-wise changing of magnetic behavior of iron oxide core gold shell nanoparticles from super paramagnetic to permanent magnetism at room temperature, on step-wise biofunctionalization with leutenizing hormone and releasing hormone (LHRH) through cysteamine linker. The observed permanent magnetism at room temperature in LHRH-capped gold nanoshells provides opportunities to extend fundamental investigations of permanent magnetism to other novel nanostructures and biofunctionalized nano gold architectures, simultaneously opening the way to newer applications, especially to those in biomedicine. KeywordsIron oxide nanoparticles; SPION; Gold nanoshell; SPION@Au; Thiol capping; leutenizing hormone and releasing hormone (LHRH); Biofunctionalization It is well known that bulk gold is diamagnetic due to counteraction of paramagnetic behavior of conduction electrons by orbital and ionic core diamagnetism. On the other hand, single gold atoms are paramagnetic because of the unpaired 6s electron. 1 There is a distinct change in the magnetism as one goes from gold atoms to nano gold and further to bulk gold and these fundamental changes in the magnetism are interesting from basic research as well as practical applications. Adding to this is recently reported chemically induced ferromagnetism in thiol-capped gold nanoparticles. 2 The chemically induced permanent magnetism was also extended to Ag and Cu nano clusters. 3 The surprising induction of permanent magnetism, under some conditions of chemisorptions, in small nanoparticles of a bulk-diamagnetic metal is likely through an interaction of s and p orbitals of adsorbates such as thiolates with 5d-orbitals of metal atoms. This interaction is anticipated to lead to emergence of 5d-localized holes as a result of significant charge transfer occurring from the metal atoms to sulfur atoms in the adsorbate molecule. The Au L3-edge extended X-ray absorption near-edge structure (EXAFS) measurements confirm the existence of these holes in Au nanoparticles capped with thiolates. 4 , 5 This interaction between the orbitals of S and Au is ultimately responsible for the onset of magnetism in thiol-capped gold nanoclusters. Recent literature reports indicate that different types of thiol-capped Au nanoparticles showed a great variety of effects going from giant paramagnetism, 6 superparamagnetism, 7 and even to permanent magnetism. 2 , 8 * Corresponding Author: To whom correspondence should be addressed. ckumar1@lsu.edu . Supplementary Figures S1-S7 and Table S1. This material is available free of charge via the Internet at http://pubs.acs.org. We synthesized SPIONs (Fe 3 O 4 ) and gold coated SPIONs (Fe 3 O 4 @Au) modifying the procedure described previously. 16 The SPIONs@Au nanoparticles were purified magnetically making them free of unwanted residual amount of pure Au nanoparticles. The HRTEM measurements show their spherical nature and the mean size of SPIONs@Au is 6.3 ± 0.7 nm compared to 5.4 ± 0.4 nm for SPIONs (Figure 1 and S1). The particles are well dispersi...