Sriparna Datta

New guar biopolymer silver nanocomposites for wound healing applications.

Wound healing is an innate physiological response that helps restore cellular and anatomic continuity of a tissue. Selective biodegradable and biocompatible polymer materials have provided useful scaffolds for wound healing and assisted cellular messaging. In the present study, guar gum, a polymeric galactomannan, was intrinsically modified to a new cationic biopolymer guar gum alkylamine (GGAA) for wound healing applications. Biologically synthesized silver nanoparticles (Agnp) were further impregnated in GGAA for extended evaluations in punch wound models in rodents. SEM studies showed silver nanoparticles well dispersed in the new guar matrix with a particle size of ~18 nm. In wound healing experiments, faster healing and improved cosmetic appearance were observed in the new nanobiomaterial treated group compared to commercially available silver alginate cream. The total protein, DNA, and hydroxyproline contents of the wound tissues were also significantly higher in the treated group as compared with the silver alginate cream (P < 0.05). Silver nanoparticles exerted positive effects because of their antimicrobial properties. The nanobiomaterial was observed to promote wound closure by inducing proliferation and migration of the keratinocytes at the wound site. The derivatized guar gum matrix additionally provided a hydrated surface necessary for cell proliferation.

An unusual pro-inflammatory role of interleukin-10 induced by arabinosylated lipoarabinomannan in murine peritoneal macrophages

Various species of Mycobacteria produce a major cell wall-associated lipoglycan, called Lipoarabinomannan (LAM), which is involved in the virulence of Mycobacterial species. In this study, we tried to establish the role of the increased IL-10 secretion under Arabinosylated-LAM (Ara-LAM) treatment, the LAM that induces apoptosis in host macrophages or PBMC. We have studied the survival and apoptotic factors by western blotting, and estimated nitrite generation by Griess reaction, quantified iNOS mRNA by semi-quantitative RT-PCR, and ultimately the fate of the cells were studied by Flow Cytometric Analysis of AnnexinV-FITC binding. As per our observations, neutralization of released IL-10 in C57BL/6 peritoneal macrophages prior to Ara-LAM treatment, as well as macrophages from IL-10 knockout (KO) mice treated with Ara-LAM, showed significant down regulation of pro-apoptotic factors and up regulation of survival factors. These effects were strikingly similar to those when peritoneal macrophages were subjected to TNF-α and IL-12 neutralization followed by Ara-LAM-treatment. However, under similar conditions virulent Mannosylated-LAM (from Mycobacterium tuberculosis) treatment of macrophages clearly depicts the importance of IL-10 in the maintenance of pathogenesis, proving its usual immunosuppressive role. Thus, from our detailed investigations we point out an unusual pro-inflammatory action of IL-10 in Ara-LAM treated macrophages, where it behaves in a similar manner as the known Th1 cytokines TNF- α and IL-12.

Assessment of synergistic antibacterial activity of combined biosurfactants revealed by bacterial cell envelop damage

Besides potential surface activity and some beneficial physical properties, biosurfactants express antibacterial activity. Bacterial cell membrane disrupting ability of rhamnolipid produced by Pseudomonas aeruginosa C2 and a lipopeptide type biosurfactant, BS15 produced by Bacillus stratosphericus A15 was examined against Staphylococcus aureus ATCC 25923 and Escherichia coli K8813. Broth dilution technique was followed to examine minimum inhibitory concentration (MIC) of both the biosurfactants. The combined effect of rhamnolipid and BS15 against S. aureus and E. coli showed synergistic activity by expressing fractional inhibitory concentration (FIC) index of 0.43 and 0.5. Survival curve of both the bacteria showed bactericidal activity after treating with biosurfactants at their MIC obtained from FIC index study as it killed >90% of initial population. The lesser value of MIC than minimum bactericidal concentration (MBC) of the biosurfactants also supported their bactericidal activity against both the bacteria. Membrane permeability against both the bacteria was supported by amplifying protein release, increasing of cell surface hydrophobicity, withholding capacity of crystal violet dye and leakage of intracellular materials. Finally cell membrane disruption was confirmed by scanning electron microscopy (SEM). All these experiments expressed synergism and effective bactericidal activity of the combination of rhamnolipid and BS15 by enhancing the bacterial cell membrane permeability. Such effect of the combination of rhamnolipid and BS15 could make them promising alternatives to traditional antibiotic in near future.

Towards a better production of bacterial exopolysaccharides by controlling genetic as well as physico-chemical parameters

Bacterial extracellular polymeric substances, which are basically bacterial metabolites, have currently become a subject of great concern of modern day microbiologists and biotechnologists. Among these metabolites, bacterial exopolysaccharides or EPS, in particular, have gained a significant importance. EPS are formed by the bacteria in their late exponential or stationary phase of growth under special situations for specific purposes. They take part in the formation of bacterial biofilms. There is a great diversity in the types of EPS. Strikingly enough, a same species of bacterium can produce different types of EPS under different situations. The importance of EPS is largely because of their different applications in various industries. Now that the bacterial EPS has got the potentiality to become an upcoming tool in various futuristic applications of human benefit, the focus currently develops towards how better they can be produced in the laboratory by promoting the favorable factors for their production. While studying with different EPS forming bacteria, both the intrinsic factors like genetic configuration of the bacteria and the extrinsic factors like culture conditions under the influence of different physico-chemical parameters in order to maximize the EPS production have been taken into consideration. Both the factors have proved their worth. Hence, towards a better outcome for EPS production, it is indicated that a genetic manipulation of the bacteria should be synchronized with a proper selection of its culture condition by controlling different physico-chemical parameters.

Accentuated transdermal application of glucosamine sulphate attenuates experimental osteoarthritis induced by monosodium iodoacetate

Osteoarthritis is a chronic degenerative joint disease causing pain and disability. Glucosamine sulphate is a well known oral supplement for its treatment. The present pioneering study provides an overview of the accentuated transdermal delivery of glucosamine sulphate through the optimized gel formulation with guar gum and sodium carboxymethyl cellulose (Na-CMC). Response surface methodology based on the three-level three-factor central composite design provided the optimum concentration of guar gum, Na-CMC and glycerol for a maximum flux. The transdermal characterization, ex vivo permeation study and in vivo study were performed with optimized gel formulation. The factorial design predicted the optimum values of guar gum, Na-CMC and glycerol which were 418.53 mg, 444.97 mg and 2322.4 mg respectively for 25 g of the gel. This optimized gel demonstrated the maximum flux, i.e., 1047.46 μg cm-2 h-1. The optimized gel showed satisfactory results with respect to drug uniformity, pH, stability, rheological properties, zeta potential, drug-excipient compatibility and skin irritation. The release of the drug from the optimized transdermal gel followed the controlled first order Fickian (non-steady) release pattern. The in vivo study was carried out in a rat model of osteoarthritis induced by monosodium iodoacetate damaging the tibial plateau. In this study the optimized formulation effectively reduced the symptoms like reduction in swelling of the knee joint, gross changes in digitized radio images and morphological and histopathological alterations. Additionally the changes in the release pattern of the proinflammatory cytokine tumor necrosis factor-α illustrated the efficacy of the transdermal gel for the treatment of experimental osteoarthritis. Thus the optimized gel was found to be a unique potential vehicle for transdermal application of glucosamine sulphate which effectively attenuates the experimental osteoarthritis.

Supercritical Fluid Chromatography: A Green Approach for Separation and Purification of Organic and Inorganic Analytes

‘Supercritical fluid’ describes a gas or liquid at conditions above its critical point. A greater range of solvent properties can be achieved with Supercritical fluid as a single solvent by careful manipulation of temperature and pressure at the supercritical state. Supercritical fluids are attractive media for several chemical reactions having better control over the reaction rates in different areas of biochemistry, polymer chemistry and environmental science. Supercritical fluid extraction (SFE), a rapid, convenient, efficient, and selective method has been used successfully for the separation of analytes prior to supercritical fluid chromatography (SFC), which is a relatively recent chromatographic technique and is commercially available since 1982. SFC significantly reduces the usage of organic solvents and wastes by using supercritical CO2 as the mobile phase. The important principles of green chemistry that are applicable to green chromatography includes prevention of waste, use of safer solvents and increasing energy efficiency. All these factors are taken care of in SFC which combines some of the best features of HPLC as well as GC. Analytes that cannot be vaporized for analysis by gas chromatography or have no functional groups for detection by the usual liquid chromatography techniques, can be separated and detected using SFC. By now SFC has been applied to wide variety of materials including natural products, pharmaceuticals, foods, pesticides, herbicides, surfactants, polymers and polymer additives, heavy metals, fossils fuels, petroleum, explosives and propellants. SFC has now become an attractive alternative for chiral drug separation.

Novel Starch-PVA Polymer for Microparticle Preparation and Optimization Using Factorial Design Study.

The aim of our present work was to optimize the ratio of a very novel polymer, starch-polyvinyl alcohol (PVA), for controlled delivery of Ornidazole. Polymer-coated drug microparticles were prepared by emulsion method. Microscopic study, scanning electron microscopic study, and atomic force microscopic study revealed that the microparticles were within 10 micrometers of size with smooth spherical shape. The Fourier transform infrared spectroscopy showed absence of drug polymer interaction. A statistical 32 full factorial design was used to study the effect of different concentration of starch and PVA on the drug release profile. The three-dimensional plots gave us an idea about the contribution of each factor on the release kinetics. Hence this novel polymer of starch and polyvinyl alcohol can be utilized for control release of the drug from a targeted delivery device.

Study of the Potential of Two Isolated Microorganisms to Degrade Various Petroleum Fractions

Biodegradation of petroleum by the microorganisms in polluted site has been gaining attention from the environment clean-up point of view. Two isolated organisms Acinetobacter junii CTA3 and Pseudomonas aeruginosa OCD1 were tested for their petroleum degrading ability in liquid Bushnell-Hass broth. Both the organisms degraded higher boiling petroleum fractions more efficiently. The strain OCD1 showed better degrading ability than the strain CTA3. The highest degradation of 47% and 57% was obtained with diesel after 20 days of incubation by the organism CTA3 and OCD1 respectively. Also it was observed that, most of the oils were degraded in first 10 days of incubation for both the isolates.