Evaluation of drug release efficiency and antibacterial property of a pH-responsive dextran-based silver nanocomposite hydrogel.

The bioavailability of curcumin (CUR), a highly lipophilic and commonly used anticancer drug, is mainly affected by its poor solubility in aqueous environment and quick metabolism. These challenges can be met by employing delivery systems. Nanocomposite materials have been used as delivery systems to enhance the solubility and dissolution rate of the drug. This study aims to develop dextran-graft-poly(4-acryloylmorpholine) silver nanocomposite using a microwave-assisted method to evaluate its drug-release efficiency and antimicrobial activity. The materials were characterized by FT-IR, FE-SEM, EDS, XRD, HR-TEM, TGA, and BET techniques. Drug loading and release efficiency were evaluated using CUR as the model drug. The swelling and drug release studies were conducted in buffer solutions of pH 1.2 and 7.4. Staphylococcus aureus and Escherichia coli were employed to evaluate the antibacterial activity. The cytotoxicity was assessed by MTT assay against the breast MCF-10. Higher swelling and drug release were observed at pH 1.2 than 7.4. Nanocomposite hydrogel exhibited antibacterial activity against the tested bacterial strains. Cytotoxicity study proved the safety of the developed matrix. The results suggest the developed nanocomposite hydrogel to be a promising polymer matrix for the sustained release of CUR for cancer treatment that requires infectious control.

Past, present and future of biomedical applications of dextran-based hydrogels: A review.

This review extensively surveys the biomedical applications of hydrogels containing dextran. Dextran has gained much attention as a biomaterial due to its distinctive properties such as biocompatibility, non-toxicity, water solubility and biodegradability. It has emerged as a critical constituent of hydrogels for biomedical applications including drug delivery devices, tissue engineering scaffolds and biosensor materials. The benefits, challenges and potential prospects of dextran-based hydrogels as biomaterials are highlighted in this review.

Evaluation of gum ghatti-g-poly(itaconic acid) magnetite nanocomposite as an adsorbent material for water purification.

A porous hydrogel nanocomposite has been made by grafting poly(itaconic acid) on the polysaccharide, gum ghatti and by embedding magnetite nanoparticles in the copolymer gel matrix. This novel functional material Ggh-g-PIA/Fe3O4 was characterized by FTIR, TGA, SEM, EDS, XRD, BET, Zeta potential measurements and VSM techniques. The nanocomposite possesses mesoporous structure with high surface area and exhibits super-paramagnetic behavior due to the presence of magnetite nanoparticles. The hydrogel nanocomposite was evaluated as an adsorbent material for removal of dyes and divalent metal ions. Significant adsorption capacities of 410.2, 387.6, 416.5 and 401.4 mg g-1 towards methylene blue, rhodamine 6G, Cu (II) and Hg (II) ions respectively were observed. The adsorption isotherms were well described by the Freundlich isotherm model and kinetic studies demonstrated the adsorption to be a pseudo second order kinetic process. Intraparticle diffusion model suggested adsorption to occur by a multi-step diffusion process. Thermodynamic studies indicated a spontaneous and endothermic adsorption. Further, the desorption study indicated the possibility of successful regeneration of the adsorbent. A high removal efficiency, recyclability, convenient recovery after use due to the magnetic nature makes this polysaccharide based nanocomposite an environment friendly adsorbent material for water purification.

Hybrid nanocomposite of kappa-carrageenan and magnetite as adsorbent material for water purification.

A novel polysaccharide based hydrogel; kappa-carrageenan grafted with N-hydroxyethylacrylamide (κC-g-PHEAA) was synthesized via microwave assisted free radical polymerization process. A hybrid nanocomposite has also been made by incorporation of Fe3O4 nanoparticles into the κC-g-PHEAA network. The materials were characterized by FTIR, TGA, XRD, SEM, BET and VSM techniques. The nanocomposite exhibited super-paramagnetic behavior. The κC-g-PHEAA and κC-g-PHEAA/Fe3O4 presented significant adsorption capacity towards cationic dyes, methylene blue (MB) and rhodamine 6G (R6G); and metal ions, Cu(II) and Hg(II) from aqueous solution. The magnetite nanoparticles enhance the adsorption characteristics of the hydrogel and enables easy separation of the adsorbent with an external magnetic field. Adsorption process is observed to follow both Langmuir and Freundlich isotherm models for R6G and Freundlich isotherm model for MB, Cu(II) and Hg(II). The adsorption was found to be a pseudo first order process for MB and pseudo second order process for R6G, Cu(II) and Hg(II). Thermodynamic studies have shown the adsorption of dyes and metal ions to be spontaneous and endothermic in nature. The desorption studies revealed the efficient recovery of adsorbate species. The study indicates that the synthesized adsorbents have potential applications for the removal of dyes and metal ions from wastewater.

Magnetite nanoparticle embedded Pectin-graft-poly(N-hydroxyethylacrylamide) hydrogel: Evaluation as adsorbent for dyes and heavy metal ions from waste water.

A pectin (Pec) based gel has been made by grafting N-hydroxyethylacrylamide (HEAA) on pectin using potassium peroxodisulphate as initiator and N,N-methylenebisacrylamide as crosslinker under microwave irradiation. The magnetite (Fe3O4) nanoparticles were incorporated within this gel via in situ diffusion of Fe2+ and Fe3+ followed by reaction with ammonia solution. The synthesized gel, pectin-graft-poly(N-hydroxyethylacrylamide) (Pec-g-PHEAA); and the magnetite containing composite (Pec-g-PHEAA/Fe3O4) were characterized by FTIR, TGA, XRD, BET and SEM techniques. The magnetic property measurement indicated ferromagnetic nature of the nanocomposite. The Pec-g-PHEAA and Pec-g-PHEAA/Fe3O4 systems were evaluated for removal of dye and metal ions from aqueous solution using Rhodamine 6G (R6G), a cationic dye; Cu(II) and Hg(II) ions. Both adsorbents showed significant adsorption capacity towards these species, with greater adsorption capacity in case of Pec-g-PHEAA/Fe3O4. Adsorption process is observed to follow both Langmuir and Freundlich isotherm models for R6G dye and Freundlich isotherm model for Cu(II) and Hg(II) ions. The adsorption was found to be a pseudo first order process for R6G and pseudo second order process for Cu(II) and Hg(II) ions. The positive values of ∆H0 and the negative values of ∆G0 indicated the adsorption process to be endothermic and spontaneous.

Pectin-based silver nanocomposite film for transdermal delivery of Donepezil.

A novel pectin-based silver nanocomposite film has been synthesized with the aid of microwave, using green technology and its capacity to adsorb and deliver anti-Alzheimer's drug Donepezil (DPZ) has been investigated. The nanocomposite exhibited excellent adsorption and release efficiency. The pristine and the drug loaded films were characterized using FTIR, TGA, XRD and FESEM-EDS techniques. The DPZ release capacity of the nanocomposite in phosphate buffer saline solution was found to be 94.33 ±â€¯2.12% during 5 days period. Along with the drug, about 92 kcps silver nanoparticles were observed to be released from the film leading to enhanced activity of the system. The drug release followed zero order kinetics and non-Fickian type of diffusion. Toxicity studies of the nanocomposite film conducted with sheep erythrocytes showed <9% hemolysis indicating the non-toxic and blood compatible nature. Further, the antimicrobial activity of the nanocomposite film against S. aureus and E. coli was quite significant compared to the standard antibiotics. These results reveal the nanocomposite film to be appropriate for the transdermal application avoiding the contamination due to the continuous contact of sweat and moisture from the skin.

Karaya gum-graft-poly(2-(dimethylamino)ethyl methacrylate) gel: An efficient adsorbent for removal of ionic dyes from water.

In the present study, a novel hydrogel based on the polysaccharide, 'Karaya gum' has been synthesised by graft copolymerization and evaluated as an adsorbent for the removal of ionic dyes from aqueous solution. The hydrogel was made by simultaneous grafting and cross linking of Karaya gum using 2-(dimethylamino)ethyl methacrylate (DMAEMA) and N,N'-methylene-bis-acrylamide via microwave irradiation. The graft copolymer gel was characterized by FTIR, TGA, SEM techniques. The swelling of the gel studied in buffer media of varying pH revealed a pH responsive behaviour with a maximum swelling in neutral pH and a minimum swelling at pH 1.2. The temperature dependent swelling study indicated 40 °C as the lowest critical solution temperature. Kinetic studies indicated the swelling to be a second order process with Fickian diffusion as the water transport mechanism. The adsorption studies indicated maximum adsorption capacity of 89.28 and 101.42 mg/g towards methylene blue and indigo carmine respectively. The dye adsorption data is found to fit well with pseudo- second order kinetic model and the Freundlich adsorption isotherm model. The adsorption was found to be a multistep process with surface adsorption followed by intraparticle diffusion. Thermodynamic studies revealed the adsorption of dyes to be spontaneous.

Application of pectin­zinc oxide hybrid nanocomposite in the delivery of a hydrophilic drug and a study of its isotherm, kinetics and release mechanism.

Pectin-based gel and its nanocomposite with zinc oxide have been compared for their capacity to release Donepezil for the possible use as an implantable drug delivery platform for the treatment of Alzheimer's disease. Adsorption capacities of the samples were determined as a function of pH, temperatures, concentrations of the drug, and the mass of the adsorbent. The nanocomposite exhibited significant adsorption compared to the parent gel. Adsorption data for the nanocomposite system fits well with Langmuir model and followed pseudo-first order kinetics, while that of the parent polymeric system followed pseudo-second-order kinetics. Donepezil adsorbed polymeric samples were prepared and evaluated for tensile strength, swelling index, folding endurance and characterized by FTIR, FESEM, EDS, XRD and TGA techniques. The desorption of zinc oxide was also monitored using the dynamic light scattering technique. The in vitro drug release study indicated desorption of Donepezil to the maximum extent of ~88% and 46% during 5 days period from the nanocomposite and the parent gel respectively. The developed systems showed negligible (<10%) percentage of hemolysis after incubation with sheep erythrocytes. In conclusion, the developed pectin-based nanocomposite can be explored as a potential platform for the development of implantable drug delivery systems for chronic diseases.