Showing papers by "Prathap Haridoss published in 2018"

Novel nano-cocoon like structures of polyethylene glycol–multiwalled carbon nanotubes for biomedical applications

Abstract: In this article, we report the synthesis and use of a novel drug delivery particle, based on bio-compatible polymer polyethylene glycol (PEG-400) and multi-walled carbon nanotubes (MWCNTs). MWCNTs in PEG-400 were broken into small tubes by vortex mixing with tungsten-carbide balls for about 15 h. Length separation of MWCNTs was then done using differential centrifugation with various concentrations of PEG-400. The separated MWCNTs in PEG solution were further pelletized using high speed centrifugation and re-dispersed in water. Novel cocoon like oval nanoparticles of about 100–200 nm size was observed in one of the centrifuged fractions. TEM shows that the cocoons primarily have PEG enclosing few MWCNTs. However, similar structures were not found when differential centrifugation was done without MWCNTs. These nano-cocoons are hemo-compatible, non-toxic to mice fibroblast cell lines (L929), have great potential to be used as nano biomaterials and they could be loaded with naturally anti-cancerous drug curcumin. The cocoon–curcumin complex is dispersible in saline and could be internalized by brain cancer cells (C6 glioma) while free curcumin dispersed in saline could not enter C6 glioma cells.

Solid Particle Erosion of Nanocrystalline Nickel Coatings: Influence of Grain Size and Adiabatic Shear Bands

Abstract: The primary objective of the present study is to investigate the influence of nanocrystalline grain size on the solid particle erosion behavior of nickel. For the above purpose, 450-μm-thick nanocrystalline Ni coatings having the average grain sizes of 21, 42, 70, and 195 nm were obtained using pulsed electrodeposition (PED). All these samples along with bulk annealed Ni samples (43 μm grain size) were subjected to solid particle erosion using SiO2 particles as an erodent at a constant impact velocity of 45 m/s and two impact angles (30 and 90 deg). Erosion results indicate that bulk Ni and PED Ni coatings of grain sizes 195 and 70 nm exhibit the same erosion rate, while PED Ni coatings of 42 and 21 nm grain size exhibit marginally higher erosion rates with a clear trend of increasing erosion rate with decreasing grain size. It was also observed that the higher erosion rates exhibited by 21- and 42-nm-grain size PED Ni samples were associated with the formation of adiabatic shear bands (ASBs) originating from the eroded surface and propagating into the eroded sample. The experimental observations have been understood on the basis of a transition from a localization model for erosion for coarse-grained Ni (> 70 nm) to an ASB-induced erosion model for grain sizes less than 70 nm.

Infrared Spectroscopy Signatures of Aluminum Segregation and Partial Oxygen Substitution by Sulfur in LiNi0.8Co0.15Al0.05O2

Abstract: Substitution of aluminum in nickel-rich layered oxides plays a vital role in structural and thermal stability. Hence comprehension of aluminum distribution in nickel-rich layered oxides such as LiNi0.8Co0.15Al0.05O2 (LNCA) is crucial. However, investigation of aluminum distribution in LNCA is extremely challenging, and sophisticated techniques such as 27Al and 7Li MAS NMR, individual atom probe tomography, X-ray and neutron diffraction, and SQUID magnetic susceptibility measurements are recently employed. We demonstrate the use of a combination of versatile techniques such as X-ray diffraction, energy dispersive X-ray analysis mapping, and vacuum Fourier transform infrared spectroscopy to identify the distribution of aluminum and anion substitution at the oxygen site in LNCA synthesized by the coprecipitation-assisted solid-state reaction. The influence of metal salts used for the coprecipitation of α/β interstratified Ni1–x–yCoxAly(OH)2 (x = 0.15, y = 0/0.05) on anion substitution at the oxygen site in L...

Drug delivery nanosystems—An introduction

Abstract: Nanosystems mainly help in safe delivery of drug molecules to the target site, by minimizing the side effects. A wide range of drugs, genes, and other therapeutic molecules can be loaded onto the nanosystems, targeting various sites of action and various diseases. The use of nanosystems has facilitated the growth of drug delivery systems with multimodal functionality, which involve a combination of therapeutic molecules, therapy techniques or site of action, etc. This short review is aimed at giving a brief introduction to the different forms of nanosystems, their classification, and their future scope when applied for drug delivery systems aimed at treating cancer and other diseases.