Mariappan Rajan

Osteoblast compatibility of minerals substituted hydroxyapatite reinforced poly(sorbitol sebacate adipate) nanocomposites for bone tissue application

The main focus of this investigation is to explore minerals (M) substituted hydroxyapatite (M-HAP) as reinforcing agents to strengthen poly(sorbitol sebacate adipate) (PSSA), a biodegradable polymer for soft and hard tissue applications while not considerably compromising their biocompatibility. PSSA strengthened with different weight percentage of M-HAP nanocomposite was synthesized using a microwave irradiation technique. The functional groups within the nanocomposites were determined by Fourier transform infrared (FT-IR) spectroscopic and X-ray diffraction (XRD) analysis. X-ray photoelectron spectroscopy (XPS) further showed the interface interaction between the M-HAP and PSSA. The morphological and elemental analysis was obtained from field emission-scanning microscopy (FE-SEM) equipped with energy-dispersive X-ray (EDX) spectroscopic analysis and transmission electron microscopy (TEM). The addition of M-HAP greatly increased the mechanical, thermal properties and improved the protein adsorption ability. In vitro bioactivity in simulated body fluid (SBF) experiment and human osteosarcoma MG63 (HOS MG63) cells proliferated on the M-HAP/PSSA shows that the nanocomposite has sensible cell biocompatibility. All these observations suggest that the M-HAP/PSSA nanocomposites will be promising biomaterials for bone tissue engineering applications.

Poly-carboxylic acids functionalized chitosan nanocarriers for controlled and targeted anti-cancer drug delivery.

The present study evaluates the in-vitro cisplatin (CDDP) release from four different poly oxalates cross-linked chitosan (CS) nanocomposites. The poly oxalates were synthesized from the reaction of four different dicarboxylic acids with ethylene glycol (EG). The encapsulation of CDDP on CS cross-linked with Oxalic acid-EG, Succinic acid-EG, Citric acid-EG and tartaric acid-EG carriers were carried out by the ionic gelation technique. The poly-oxalate nanocarriers were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction studies and zeta potential analysis. The stability of poly-oxalates was calculated by the density functional theory (DFT) using Gaussview 05. Excellent drug release kinetics and good biocompatibility of nanocomposites were observed for the in-vitro analysis. The unloaded poly oxalate nanocomposites perform to have a low inherent cytotoxicity, whereas the loaded nanocomposites were as active as free CDDP in the MCF-7 cancer cell line. The tumor growth inhibitions of CDDP-loaded nanocomposites are more or equal to that of free CDDP. Taken together, these two poly oxalate nanocomposites are established as promising drug carriers for the delivery of CDDP.

Targeted delivery of rifampicin to tuberculosis-infected macrophages: design, in-vitro , and in-vivo performance of rifampicin-loaded poly(ester amide)s nanocarriers

We have developed a nano drug delivery system for the treatment of tuberculosis (TB) using rifampicin (RF) encapsulated in poly(ester amide)s nanoparticles (PEA-RF-NPs), which are biocompatible polymers. In this study, biodegradable amino acid based poly(ester amide)s (PEAs) were synthesized by the poly condensation reaction and RF-loaded NPs were fabricated by the dialysis method. The surface morphology and in-vitro drug release efficiency were examined. The effect of time and temperature on the cellular uptake of PEA-RF-NPs in NR8383 cells was evaluated. Fluorescence microscopic results of PEA-RF-NPs from NR8383 cell lines suggest its potential application in treating TB. The antibacterial activity of RF against Mycobacterium smegmatis was also evaluated. Based on these results, this approach provides a new means for controlled and efficient release of RF using the PEA-NPs delivery system and is promising for the treatment of TB.

Mineral substituted hydroxyapatite coatings deposited on nanoporous TiO2 modulate the directional growth and activity of osteoblastic cells

The biocompatibility of anodized titanium (TiO2) was improved by electrophoretically deposited mineral (strontium (Sr), magnesium (Mg) and zinc (Zn)) substituted hydroxyapatite (M-HAP). The M-HAP layer was grown on the anodized Ti surface at different deposition temperatures (room temperature, 60 and 80 °C). The phases and morphologies of the M-HAP layers were influenced by the deposition temperature. The coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDX). Also, the effects of temperature and the mineral substitution of Sr, Mg and Zn for Ca on the physiochemical and biological properties of the M-HAP coatings were evaluated by the mechanical strength, ion dissolution and proliferation, alkaline phosphatase (ALP) activity and osteogenic expression of osteoblast like cells MG66 (HOS). Thus, the M-HAP deposition of TiO2 will serve as a potential candidate for orthopedic applications.

Investigation of lanthanum impregnated cellulose, derived from biomass, as an adsorbent for the removal of fluoride from drinking water

High concentrations of fluoride in drinking water can cause the disease fluorosis. Our scope goal is to develop an effective biopolymeric adsorbent for the removal of fluoride to below a specific safety limit set by the World Health Organization. In this study, the natural adsorbent material cellulose was impregnated with lanthanum chloride and effectiveness in adsorbing fluoride was confirmed by FT-IR, XRD, and SEM coupled with EDX techniques. The adsorption data were analyzed by Freundlich, Langmuir, and Redlich-Peterson isotherms. The adsorption on cellulose and Lanthanum impregnated Cellulose (LaC) obeyed the pseudo second order kinetic model and thermodynamic parameters were shows the adsorption process was spontaneous and feasible. The high adsorption capacity of LaC was developed from waste materials through an easy procedure, has potential for application to efficient defluoridation. In future, the potential LaC adsorbent will be used for designing of household defluoridation unit for effective and economical fluoride removal.

Development of extended-voyaging anti-oxidant Linked Amphiphilic Polymeric Nanomicelles for Anti-Tuberculosis Drug Delivery

Amphiphilic chitosan-graft-poly(caprolactone)/(ferulic acid) (CS-g-PCL/FA) multi-co-polymers were fabricated by microwave-assisted ring opening polymerization followed by an 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC)-mediated coupling reaction and characterized by Fourier transformed infrared (FTIR) spectroscopy. Graft copolymers self-assembled into nanomicelles, and were able to incorporate rifampicin (RF) into their hydrophobic inner cores. X-ray diffraction (XRD) patterns were applied to characterize the crystal structures of graft polymers and the effects of RF on micelle morphology. Empty and RF-loaded CS-g-PCL/FA nanomicelles underwent swelling and degradation in acidic pH conditions. Scanning electron microscopy, transmission electron microscopy, and dynamic light scattering revealed that the self-assembled, RF-loaded micelles were spherical, with an average size of 100-210nm. An in vitro study conducted at 37°C demonstrated that RF and FA release from micelles at pH 5.3 was much faster than that at pH 7.4. The RF and FA release was significantly accelerated by switching to an acidic pH, owing to swelling of the micelles at lower pH values caused by the rapid degradation of ester and amide bonds present in the micelles. Fluorescence micrographs revealed successful entry of the polymeric micelles into A549cell lines. Thus, graft polymeric micelles have promising potential for delivery of hydrophobic antitubercular drugs and may improve therapeutic approaches for tuberculosis.

Surface functionalization of natural lignin isolated from Aloe barbadensis Miller biomass by atom transfer radical polymerization for enhanced anticancer efficacy

Lignin (LIG), one of the major natural polymers in the biomass is widely used for various industrial and biomedical applications, mainly in its modified form of grafted lignin. The present study focuses on the isolation of lignin from Aloe barbadensis Miller by a microwave extraction technique and its applicability as a medicinal biomass. The isolated lignin was used for the synthesis of a drug carrier by grafting with methacrylate (MA). Lignin grafted methacrylate was synthesised (LIG-g-MA) via atom transfer radical polymerization (ATRP). 5-Fluorouracil (5-FU) was used as a model cancer drug and it was encapsulated on the hollow nanocarrier by the emulsion/solvent evaporation technique. While NMR spectroscopy elucidates the structure of the isolated lignin, FT-IR and XRD techniques address the binding nature and crystalline character of 5-FU loaded carrier. The surface morphology of the isolated lignin, grafted lignin and drug-loaded carrier was confirmed with SEM and TEM techniques. The encapsulation efficiency and in vitro drug release were studied to determine the efficiency of the carrier. The cell viability and cytotoxicity effect of 5-FU loaded on LIG-g-MA and unloaded LIG-g-MA were performed against MCF-7 and VERO cell lines. In short, the modified natural lignin based on LIG-g-MA hollow-nanofibrous material has been shown to be a potentially useful biocompatible nanocarrier in chemotherapy for cancer treatment.

Magneto-chemotherapy for cervical cancer treatment with camptothecin loaded Fe3O4 functionalized β-cyclodextrin nanovehicle

We portray a novel way to deal with the synthesis of iron oxide magnetic nanoparticle incorporated β-cyclodextrin (β-CD) nanocarrier stabilized by ethylenediamine tetra acetic acid (EDTA), which obtained remarkable biocompatibility and biodegradability. The functionality, crystalline nature, morphology and thermal decomposition nature of Fe3O4, β-CD–EDTA–Fe3O4 and β-CD–EDTA–Fe3O4/CPT nanocarriers were confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The mechanistic action of camptothecin (CPT) on cancer cells was studies relying to incorporation with the topoisomerase (topo I) and DNA complex formation. This prevented DNA re-ligation, causing DNA damage which resulted in apoptosis in cervical cancer (HeLa) cells. We noticed a higher number of cells arrested in the G1 phase with a decreasing cell count in the S phase and the G2/M phase at a lower concentration of β-CD–EDTA–Fe3O4/CPT. Consequently, via conjugation with Fe magnetic nanoparticles (MNPs), the molecular recognition between β-CD and target the cancerous cells make this nanovehicle a promising candidate for the non-invasive treatment of HeLa cells.

Iron and iron oxide nanoparticles are highly toxic to Culex quinquefasciatus with little non-target effects on larvivorous fishes

The control of filariasis vectors has been enhanced in several areas, but there are main challenges, including increasing resistance to insecticides and lack of cheap and eco-friendly products. The toxicity of iron (Fe0) and iron oxide (Fe2O3) nanoparticles has been scarcely investigated yet. We studied the larvicidal and pupicidal activity of Fe0 and Fe2O3 nanoparticles against Culex quinquefasciatus. Fe0 and Fe2O3 nanoparticles produced by green (using a Ficus natalensis aqueous extract) and chemical nanosynthesis, respectively, were analyzed by UV–Vis spectrophotometry, FT-IR spectroscopy, XRD analysis, SEM, and EDX assays. In larvicidal and pupicidal experiments on Cx. quinquefasciatus, LC50 of Fe0 nanoparticles ranged from 20.9 (I instar larvae) to 43.7 ppm (pupae) and from 4.5 (I) to 22.1 ppm (pupae) for Fe2O3 nanoparticles synthesized chemically. Furthermore, the predation efficiency of the guppy fish, Poecilia reticulata, after a single treatment with sub-lethal doses of Fe0 and Fe2O3 nanoparticles was magnified. Overall, this work provides new insights about the toxicity of Fe0 and Fe2O3 nanoparticles against mosquito vectors; we suggested that green and chemical fabricated nano-iron may be considered to develop novel and effective pesticides.

Impact of dengue virus (serotype DENV-2) infection on liver of BALB/c mice: A histopathological analysis

In this research, we characterized the histopathological impact of dengue virus (serotype DENV-2) infection in livers of BALB/c mice. The mice were infected with different doses of DENV-2 via intraperitoneal injection and liver tissues were processed for histological analyses and variation was documented. In the BALB/c mouse model, typical liver tissues showed regular hepatocyte architecture, with normal endothelial cells surrounding sinusoid capillary. Based on histopathological observations, the liver sections of BALB/c mice infected by DENV-2 exhibited a loss of cell integrity, with a widening of the sinusoidal spaces. There were marked increases in the infiltration of mononuclear cells. The areas of hemorrhage and micro- and macrovesicular steatosis were noted. Necrosis and apoptosis were abundantly present. The hallmark of viral infection, i.e., cytopathic effects, included intracellular edema and vacuole formation, cumulatively led to sinusoidal and lobular collapse in the liver. The histopathological studies on autopsy specimens of fatal human DENV cases are important to shed light on tissue damage for preventive and treatment modalities, in order to manage future DENV infections. In this framework, the method present here on BALB/c mouse model may be used to study not only the effects of infections by other DENV serotypes, but also to investigate the effects of novel drugs, such as recently developed nano-formulations, and the relative recovery ability with intact immune functions of host.