Synthesis, Characterization, and Cytotoxicity Evaluation of Polyethylene Glycol-Coated Iron Oxide Nanoparticles for Radiotherapy Application.

BACKGROUND: Treatment methods for cancer that are widely being utilized affect both normal and cancerous cells. We report synthesis polyethylene glycol (PEG)-coated Fe3O4 nanoparticles (NPs) and its characteristic properties and appraise its potential as a promising radiation sensitizer candidate in radiotherapy that improves cancer treatment and reduces side effects of radiation. MATERIALS AND METHODS: PEG-coated Fe3O4 NPs were synthesized by chemical coprecipitation method and characterized by studying their size, structure, functional group, stability, magnetization, and cytotoxicity using different techniques. X-ray powder diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis results show that Fe3O4 NPs have been functionalized with PEG molecules during the course of synthesis. RESULTS: Synthesized NPs have good stability based on zeta-potential study. Dynamic light-scattering results reveal that PEG-coated Fe3O4 has a greater hydrodynamic size than bare Fe3O4. Transmission electron microscopy (TEM) micrograph exhibited that NPs are roughly spherical with size in range of 10-20 nm. Saturation magnetization value of PEG-coated and bare Fe3O4 also confirms coating and shows superparamagnetic behavior. Cytotoxicity evaluation study indicated that PEG-coated Fe3O4 is biocompatible on L929 and toxic on Michigan Cancer Foundation-7 (MCF-7) (breast cancer cells). CONCLUSION: These characterized properties of PEG-coated Fe3O4 NPs show that it could be used as a potential radiosensitizer candidate in radiotherapy to significantly improve cancer treatment and minimize painful side effects of radiation.

Highly Stable Cycling of Silicon-Nanographite Aerogel-Based Anode for Lithium-Ion Batteries.

Silicon anodes are considered as promising electrode materials for next-generation high capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge-discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nanographite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.

Hybrid chitosan-ZnO nanoparticles coated with a sonochemical technique on silk fibroin-PVA composite film: A synergistic antibacterial activity.

The hybrid chitosan-ZnO nanoparticles (C@ZnO NPs) are synthesized and coated on Silk fibroin-polyvinyl alcohol (SF-PVA) composite film by a sonochemical coating process. These are systematically studied for their synergistic antibacterial activity and reported. The coated composite films show the excellent antibacterial activity against Gram-positive and Gram-negative bacteria. The composite films are characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) studies. The specific surface area and porosity are studied by Brunauer-Emmett-Teller (BET) analysis under nitrogen gas adsorption. The swelling degree, mechanical property and cell viability study of coated and uncoated composite films are investigated. The results showed that the specific surface area, porosity, swelling degree, and mechanical property of coated composite films increased with increasing the concentrations of C@ZnO NPs on SF-PVA composite film. Cell viability study confirmed the cytocompatible nature of all the C@ZnO NPs coated composite films. Thus, obtained properties of composite films reveal the potential of this material which can be used as antibacterial wound dressing applications.

Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries.

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g-1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g-1.