Dual Modality FeS Nanoparticles with Reactive Oxygen Species-Induced and Photothermal Toxicity toward Pathogenic Bacteria.

Bacterial infections pose a major threat to human health, primarily because of the evolution of mutated strains that are resistant to antibiotic treatment. As a viable alternative, several nanoparticles have emerged as attractive antibacterial agents. Herein, we report the development of iron sulfide (FeS) nanoparticles that show dual-modality therapy: namely reactive oxygen species (ROS)-induced toxicity and red-laser induced photothermal therapy. The aqueous synthesized nanoparticles have been characterized based on their size, shape, crystallinity, and magnetic and optical properties. These nanoparticles showed sustained release of Fe2+ ions in an aqueous dispersion. They also have a high absorption cross-section in the visible and near infra-red regions and could be excited by a continuous wave diode laser of wavelength 635 nm leading to significant hyperthermia. Nanoparticle treatment, followed by light irradiation, led to significant cell death in two ghastly pathogenic bacterial strains. Stepwise enhancement of intrabacterial ROS levels, as a result of nanoparticle treatment followed by light activation, has been identified as the primary antibacterial mechanism.

Preparation and characterization of superparamagnetic iron oxide nanoparticles for magnetically guided drug delivery.

Iron oxide nanoparticles have unique magnetic properties and therefore readily respond to applied magnetic fields. Moreover, their surfaces can be used to attach active molecules via various covalent or noncovalent interactions. Thus, they can be used as drug carriers for magnetically controlled delivery to specific biological sites of interest. In the present study, we have synthesized aqueous dispersed samples of citric acid-capped iron oxide nanoparticles, and the anticancer drug doxorubicin was then linked with these superparamagnetic iron oxide nanoparticles via a simple noncovalent interaction. Our results show that the conjugated drug releases from the nanoparticles in a sustained manner. The cellular uptake of these nanoparticles was found to be substantial, although it can be further enhanced using magnetic guidance. These nanoparticles (drug free) were found to be nontoxic to cells; however, upon drug conjugation, drug-induced toxicity was observed, owing to the slow release of drug from the nanoparticles.

Multifunctional biosynthesized silver nanoparticles exhibiting excellent antimicrobial potential against multi-drug resistant microbes along with remarkable anticancerous properties.

This study demonstrates the therapeutic potential of silver nanoparticles (AgNPs), which were biosynthesized using the extracts of Citrus maxima plant. Characterization through UV-Vis spectrophotometry, Dynamic Light Scattering (DLS), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) confirmed the formation of AgNps in nano-size range. These nanoparticles exhibited enhanced antioxidative activity and showed commendable antimicrobial activity against wide range of microbes including multi-drug resistant bacteria that were later confirmed by TEM. These particles exhibited minimal toxicity when cytotoxicity study was performed on normal human lung fibroblast cell line as well as human red blood cells. It was quite noteworthy that these particles showed remarkable cytotoxicity on human fibrosarcoma and mouse melanoma cell line (B16-F10). Additionally, the apoptotic topographies of B16-F10 cells treated with AgNps were confirmed by using acridine orange and ethidium bromide dual dye staining, caspase-3 assay, DNA fragmentation assay followed by cell cycle analysis using fluorescence-activated cell sorting. Taken together, these results advocate promising potential of the biosynthesized AgNps for their use in therapeutic applications.