Rajesh Thakur

Sodium alginate and gum acacia hydrogels of ZnO nanoparticles show wound healing effect on fibroblast cells

An ideal biomaterial for wound dressing applications should possess antibacterial and anti-inflammatory properties without any toxicity to the host cells while providing the maximum healing activity. Zinc oxide nanoparticles (ZnONPs) possess antimicrobial activity and enhance wound healing, but the questions regarding their safety arise before application to the biological systems. We synthesized ZnONPs-loaded-sodium alginate-gum acacia hydrogels (SAGA-ZnONPs) by cross linking hydroxyl groups of the polymers sodium alginate and gum acacia with the aldehyde group of gluteradehyde. Here, we report the wound healing properties of sodium alginate/gum acacia/ZnONPs, circumventing the toxicity of ZnONPs simultaneously. We demonstrated the concentration-dependent zones of inhibition in treated cultures of Pseudomonas aerigunosa and Bacillus cereus and biocompatability on peripheral blood mononuclear/fibroblast cells. SAGA-ZnONPs hydrogels showed a healing effect at a low concentration of ZnONPs using sheep fibroblast cells. Our findings suggest that high concentrations of ZnONPs were toxic to cells but SAGA-ZnONPs hydrogels significantly reduced the toxicity and preserved the beneficial antibacterial and healing effect.

Biogenesis of copper nanoparticles using peel extract of Punica granatum and their antimicrobial activity against opportunistic pathogens

ABSTRACT Copper nanoparticles (CuNPs) were biologically synthesized using peel extract of Punica granatum as reducing agent as well as capping agent. On treatment of aqueous solutions of CuSO4·5H2O with peel extract of P. granatum, stable CuNPs were formed. UV-Visible spectrophotometer analysis confirmed the formation of CuNPs. The synthesized nanoparticles were characterized with Fourier transform infrared spectroscopy, particles size analyzer and transmission electron microscopy (TEM). The electron microscopy analysis of CuNPs indicated that they ranged in size from 15 to 20 nm. The biologically synthesized CuNPs demonstrated high antibacterial activity against opportunistic pathogens, that is, Micrococcus luteus MTCC 1809, Pseudomonas aeruginosa MTCC 424, Salmonella enterica MTCC 1253 and Enterobactor aerogenes MTCC 2823 in vitro. Nanoparticles synthesized biologically using plant extracts have the potential to serve as possible ecofriendly alternatives to chemical and physical methods for biomedical applications and research.! GRAPHICAL ABSTRACT

Enhancement of anti-inflammatory activity of glycyrrhizic acid by encapsulation in chitosan-katira gum nanoparticles

Efforts were made to improve the bioavailability and efficacy of Glycyrrhizic acid, a triterpentine saponin obtained from Glycyrrhiza glabra, having several pharmacological properties, by its encapsulation in biocompatible biopolymeric nanoparticles. Polycationic chitosan and polyanionic gum katira were used to prepare nanoparticles by ionic complexation method. Glycyrrhizic acid was loaded into the nanoparticles and was then examined for change in its in vivo anti-inflammatory activity against carrageenan-induced rat hind paw inflammation. The effects of concentrations of glycyrrhizic acid, chitosan and katira gum, upon particle size and encapsulation efficiency of glycyrrhizic acid were studied with the help of response surface methodology employing 3-factor, 3-level central composite experimental design. Particle size and encapsulation efficiency of optimized nanoparticulate formulation were 175.8nm and 84.77%, respectively. Particles were observed in transmission electron microscopy to be spherical in shape and 80nm in size. FTIR analysis indicated electrostatic interactions between carboxyl groups of ammonium glycyrrhizinate and amino groups of chitosan. In vitro drug release studies indicated that glycyrrhizic acid was released from the nanoparticles following zero-order kinetics and that there was a sustained release of the drug with 90.71% of it being released over a 12h period, and that the mechanism of release of glycyrrhizic acid from the nanoparticles was a combination of diffusion and erosion of the polymer matrix. In-vivo anti inflammatory efficacy of glycyrrhizic acid clearly improved upon encapsulation in chitosan-katira gum nanoparticles, by overcoming the limited bioavailability of its other forms.

Ketoconazole encapsulated in chitosan-gellan gum nanocomplexes exhibits prolonged antifungal activity.

The objective of the present study was to prepare ketoconazole loaded chitosan-gellan gum (CSGG) nanoparticles and to evaluate them for antifungal activity against Aspergillus niger. Ketoconazole loaded CSGG nanoparticles were prepared by electrostatic complexation technique using chitosan (CS) as cationic polymer and gellan gum (GG) as anionic polymer with ketoconazole as drug. It was observed that the effect of gellan gum on particle size was more pronounced in comparison to chitosan and increase in its concentration resulted in a significant increase in particle size but decrease in zeta potential. Whereas, increase in concentration of chitosan resulted in increase in zeta potential. The particle size and zeta potential of optimal formulation was 155.7±26.1nm and 32.1±2.8mV which obtained at concentration of chitosan (0.02% w/v) and gellan gum (0.01% w/v). On comparative evaluation, ketoconazole loaded CSGG nanoparticles showed significantly higher antifungal activity against Aspergillus niger than dummy CSGG nanoparticles (without drug) and drug individually.

Interaction Of ZnO Nanoparticles With Food Borne Pathogens Escherichia coli DH5α and Staphylococcus aureus 5021 & Their Bactericidal Efficacy

Bactericidal activity of ZnO nanoparticles (np) against the food borne pathogens E. coli DH5α (Gram−ve) and & S. aureus 5021 (Gram+ve), and the mechanism of their interaction with target microbes was studied. Bactericidal activity of ZnO np was attributed to disruption of cell membrane causing cytoplasmic leakage, which was measured by quantifying the leakage of nucleic acids, proteins and K+ ions from the cells using UV‐VIS Spectrophotometry and Atomic Absorption Spectrophotometry, respectively. Cell membrane disruption was observed through TEM. It is proposed that both the abrasiveness and the surface oxygen species of ZnO np are responsible for their biocidal properties.

Enhancement of anti-inflammatory activity of bromelain by its encapsulation in katira gum nanoparticles

Bromelain-loaded katira gum nanoparticles were synthesized using 3 level optimization process and desirability approach. Nanoparticles of the optimized batch were characterized using particle size analysis, zeta potential, transmission electron microscopy and Fourier-transform infrared spectroscopy. Investigation of their in vivo anti-inflammatory activity by employing carrageenan induced rat-paw oedema method showed that encapsulation of bromelain in katira gum nanoparticles substantially enhanced its anti-inflammatory potential. This may be attributed to enhanced absorption owing to reduced particle size or to protection of bromelain from acid proteases.

Regioselective synthesis and antimicrobial evaluation of some thioether–amide linked 1,4-disubstituted 1,2,3-triazoles

ABSTRACT A series of 1,4-disubstituted 1,2,3-triazoles having thioether as well as amide linkage were synthesized from aryl(prop-2-yn-1-yl)sulfanes and 2-azido-N-substituted acetamides through Cu(I) catalyzed click reaction. Structures of newly synthesized compounds (3a–3x) were confirmed by spectral techniques like FTIR, 1H NMR, 13C NMR, and HRMS. The synthesized triazoles were evaluated for in vitro antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Compounds 3m and 3q displayed appreciable broad spectrum antimicrobial activity against tested microbial strains. The nanoformulations of compounds 3m and 3q were also prepared and examined against one bacterial strain and one fungal strain. GRAPHICAL ABSTRACT

Enhanced Antimicrobial Activity Of Antibiotics Mixed With Metal Nanoparticles

Current producers of antimicrobial technology have a long lasting, environmentally safe, non‐leaching, water soluble solution that will eventually replace all poisons and heavy metals. The transition metal ions inevitably exist as metal complexes in biological systems by interaction with the numerous molecules possessing groupings capable of complexation or chelation. Nanoparticles of metal oxides offer a wide variety of potential applications in medicine due to the unprecedented advances in nanobiotechnology research. the bacterial action of antibiotics like penicillin, erythryomycin, ampicillin, streptomycin, kanamycin etc. and that of a mixture of antibiotics and metal and metal oxide nanoparticles like zinc oxide, zirconium, silver and gold on microbes was examined by the agar‐well‐diffusion method, enumeration of colony‐forming units (CFU) and turbidimetry.

An Investigation of CNT Cytotoxicity by Using Surfactants in Different Ratio

This account reports a comparative analysis on dispersion of multiwalled and single walled carbon nanotubes with different surfactants like—Triton X‐100, Tween 20, Tween 80, and sodium dodecyl sulfate (SDS). Dispersion of CNTs has been characterized by UV–Vis spectroscopy, electron microscopy and probe microscopy. An optimum CNT‐to‐surfactant ratio has been determined for each surfactant. Surfactant concentration in different ratio is found to deteriorate the quality of nanotube dispersion. Electron microscopy analysis of a high‐surfactant sample concentration enables us to construct a plausible mechanism for increase or decrease in CNT dispersion at high surfactant concentration.

Antimicrobial Activity of Metal & Metal Oxide Nanoparticles Interfaced With Ligand Complexes Of 8‐Hydroxyquinoline And α‐Amino Acids

Antimicrobial nanotechnology is a recent addition to the fight against disease causing organisms, replacing heavy metals and toxins. In the present work, mixed ligand complexes of metals like zinc, silver etc. and metal oxide have been synthesized using 8‐hydroxyquinoline (HQ) as a primary ligand and N‐and/O‐donor amino acids such as L‐serine, L‐alanine, glycine, cysteine and histidine as secondary ligands. These complexes were characterized using different spectroscopic techniques. The complexes were tested for antifungal and antibacterial activity by using agar well diffusion bioassay.