Synthesis of porous calcium-guar gum benzoate nano-biohybrids for sorptive removal of congo red and phosphates from water.

This work aims to develop an eco-sound nano-bio-hybrid sorbent using sustainable materials for sorptive elimination of congo red and phosphates from aquatic environment. An amphipathic biopolymer derivative, high DS guar gum benzoate (GGBN) was used for entrapment of as synthesized calcium carbonate nanoparticles using solvent diffusion nano-precipitation technique. Designer nano-biohybrids were developed upon experimenting with various materials stoichiometry. SEM, XRD and EDX studies confirmed near-uniform impregnation of rhombohedral calcium carbonate crystals throughout the biopolymer matrix. Average pore size distribution and surface area of final product Ca-GGBNC, were estimated from NDLFT and BET methods respectively. Analysis of adsorption findings acquired at study temperature 27 ± 2 °C showed that the maximum adsorption capacity of Ca-GGBNC recorded qmax, 333.33 mg/g for congo red azo dye and that for phosphate was at 500 mg/g. Adsorptive removal was noted and both components followed pseudo second order kinetics. Intra-particle diffusion kinetics investigation disclosed that the boundary layer effect was prominent and the adsorption rates were not solely directed by the diffusion stage. Activation energy, Ea was to be estimated using Arrhenius equation at 56.136 and 47.015 KJ/mol for congo red and phosphates respectively. The calculated thermodynamic parameters(ΔG°, ΔH°, and ΔS°) revealed the spontaneous, feasible and endothermic sorption process. Owing to active surface area, spherical size, functional moiety and porous network, antibacterial properties of nanobiohybrid were persistent and MIC against E. coli and S. aureus were recorded at 200 µg/mL and 350 µg/mL respectively.

Guar gum propionate-kojic acid films for Escherichia coli biofilm disruption and simultaneous inhibition of planktonic growth.

Nosocomial bacterial infections associated with biofilms inspire to explore newer bactericidal strategy with eco-friendly biomaterials as sustainable alternatives. In this research work, we successfully developed bio-safe films from kojic acid(KA) and guar gum propionate(GGP) for Escherichia coli biofilm disruption and planktonic cell killing. High DS(degree of substitution = 1.52) GGP was synthesized from guar gum (GG)assisted by chaotropic ions at room-temperature. Biopolymers were routinely characterized in CHN analyzer, FT-IR, TGA and XRD analysis. KA loaded GGP films were prepared by cross-linking the molecules in presence of epichlorhydrin and two different percentages of KA were employed. Film physical and tensile properties were systematically evaluated and optimized. Water vapour permeability (WVP) and tensile strength of final film GGPFK10 were recorded at 0.741 ± 0.09gmm-1kPa-1h-1 and 19.23 MPa. KA release from GGP matrix followed controlled diffusion process. MIC of GGP was 130 µg/mL and zone of inhibition of GGPFK10 was confirmed at 16.1 mm. SEM experiments disclosed the absence of pili-like structures with squeezed and elongated cellular morphology in dead planktonic cells. Disruption of biofilms was experimented in detail by CV assay, fluorescent, light microscopic and SEM studies. The film showed excellent cell-viability on human adult dermal fibroblast (HADF)cell-line. Overall, the biosafe film would be a potent antibacterial device for treating infections against E.coli biofilms and planktonic cells.

Guar gum cinnamate ouzo nanoparticles for bacterial contact killing in water environment.

Herein we report the synthesis of newer guar gum cinnamate esters (GGC) following a Hofmeister cation guided homogeneous phase reaction. High degree of substitution (DS) guar gum cinnamate was obtained using, cinnamic acid halide reactant at a 1:3 M ratio. The biopolymer was fully characterized in FT-IR,13C NMR, XRD and thermal analysis. Nanoparticles were further developed in a facile ouzo solvent diffusion technique. SEM studies confirmed quasi spherical shape of the nanoparticles (GGCN) with an average size of 200 nm. Nanoparticles GGCN, expressed antibacterial activity against water borne gram negative and gram positive bacteria. The MIC was recorded at 300 µg mL-1against Escherichia coli and 500 µg mL-1against Staphylococcus aureus. Bacterial contact killing was confirmed from the bacterial morphology studies in SEM. Thus, nanoparticles from GGC may be employed for bacterial killing and water decontamination.

Semi-interpenetrating hydrogels from carboxymethyl guar gum and gelatin for ciprofloxacin sustained release.

The present work reports the synthesis of new generation semi-interpenetrating (s-IPN) hydrogels from carboxymethyl guar gum (CMGG) and gelatin with enhanced gel properties for suitable drug delivery applications. Hydrogels are three dimensional polymer networks which respond to water and ion interactions. Irreversible s-IPN hydrogels were prepared by CMGG interactions in gelatin and characterized in FT-IR, SEM and thermal studies. CMGG was synthesized by Hofmeister ion guided homogeneous phase reactions. The swelling kinetics of the newer s-IPN hydrogels followed Schott's pseudo second order model. Furthermore, the hydrogels were hemocompatible, non-cytotoxic and appropriate for applications in physiological environment. Model drug ciprofloxacin was loaded within the hydrogels and the drug release was found to be a combination of both diffusion and hydrogel degradation. New generation s-IPN biopolymer hydrogels of carboxymethyl guar gum and gelatin holds promise for its application as sustained drug delivery device or alternatively as hydrogel sorbents for bio-toxins and molecules of biomedical importance.

Carboxymethyl guar gum synthesis in homogeneous phase and macroporous 3D scaffolds design for tissue engineering.

Guar gum (GG) is a galactomannan obtained directly from the Cyamopsis tetragonoloba seeds pericarb. The biopolymer hydrates hugely in three chain associated coil formations. Chaotropic Hofmeister ion like lithium interacts at the hydrogen bonding sites and render GG homogenization in polar solvents like dimethyl sulfoxide. This phenomenon was used for the first time for galactomannan derivatisations in homogeneous phase. Higher degree of substitution (DS) that was hereto unattainable in GG was achieved due to Hofmeister ion assisted assembly deformations. Furthermore, carboxymethyl guar gum (CMGG, DS = 1.10) blends well in poly-vinyl alcohol (PVA) at 2:1 mass ratio and enabled hydrophilic porous scaffold design for cell propagation. CMGG-PVA scaffolds porosity was 70-90% and the tensile strength was 6.32 MPa. CMGG-PVA scaffolds were useful as cell factories and in tissue engineering. New generation guar gum derivative scaffolds were non cytotoxic and permitted cell propagation in growth medium.

Andrographolide inhibits human serum albumin fibril formations through site-specific molecular interactions.

Protein misfolding and fibrillation are the fundamental traits in degenerative diseases like Alzheimer's, Parkinsonism, and diabetes mellitus. Bioactives such as flavonoids and terpenoids from plant sources are known to express protective effects against an array of diseases including diabetes, Alzheimer's and obesity. Andrographolide (AG), a labdane diterpenoid is prescribed widely in the Indian and Chinese health care systems for classical efficacy against a number of degenerative diseases. This work presents an in depth study on the effects of AG on protein fibrillating pathophysiology. Thioflavin T fluorescence spectroscopy and DLS results indicated concentration dependent inhibition of human serum albumin (HSA) fibrillation. The results were confirmed by electron microscopy studies. HSA fibril formations were markedly reduced in the presence of AG. Fluorescence studies and UV-Vis experiments confirmed further that AG molecularly interacts with HSA at site. In silico molecular docking studies revealed hydrogen bonding and hydrophobic interactions with HSA in the native state. Thus AG interacts with HSA, stabilizes the native protein structure and inhibits fibrillation. The results demonstrated that the compound possesses anti-amyloidogenic properties and can be promising against some human degenerative diseases.

Guar gum benzoate nanoparticle reinforced gelatin films for enhanced thermal insulation, mechanical and antimicrobial properties.

This work relates to guar gum benzoate self assembly nanoparticles synthesis and nano composite films development with gelatin. Guar gum benzoate was synthesized in a Hofmeister cation guided homogeneous phase reaction. Self assembly polysaccharide nanoparticles were prepared in solvent displacement technique. Electron microscopy and DLS study confirmed uniform quasi spherical nanoparticles with ζ-potential - 28.7mV. Nanocomposite films were further developed in gelatin matrix. The film capacity augmenting due to nanoparticles incorporation was noteworthy. Superior barrier properties, reinforcing and thermal insulation effects were observed in films dispersed with 20% w/w nanoparticles. Detailed FTIR studies and thermal analysis confirmed nanoparticles interactions in the film matrix. The nanocomposite film water vapour permeability was at 0.75gmm-1kPa-1h-1, thermal conductivity 0.39Wm-1K-1 and the tensile strength were recorded at 3.87MPa. The final film expressed excellent antimicrobial properties against water born gram negative and gram positive bacteria.