Konduru Mohana Raju

Cellulose-polymer-Ag nanocomposite fibers for antibacterial fabrics/skin Scaffolds

Abstract Natural carbohydrates (polysaccharides): gum acacia (GA) and gaur gum (GG) were employed in dilute solutions: 0.3%, 0.5% and 0.7% (w/v), as effective reductants for the green synthesis of silver nanoparticles (AgNPs) from AgNO3. The formed AgNPs were impregnated into cellulose fibers after confirming their formation by utilizing ultraviolet–visible (UV–vis) spectral studies, Fourier transforms infrared (FTIR) and transmission electron microscopy (TEM). The surface morphology of the developed cellulose–silver nanocomposite fibers (CSNCFs) were examined with scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The thermal stability and mechanical properties of the CSNCFs were found to be better than cellulose fibers alone. The antibacterial activity of the nanocomposites was studied by inhibition zone method against Escherichia coli, which suggested that the developed CSNCFs can function effectively as anti-microbial agents. Hence, the developed CSNCFs can effectively used for tissue scaffolding.

Development of novel biodegradable Au nanocomposite hydrogels based on wheat: For inactivation of bacteria

The design and fabrication of novel biodegradable gold nanocomposites hydrogels were developed as antibacterial agent. Biodegradable gold nanocomposite hydrogels were developed by using acrylamide (AM) and wheat protein isolate (WPI). The gold nanoparticles were prepared as a gold colloid by reducing HAuCl(4)·XH(2)O with leaf extracts of Azadirachta indica (neem leaf) that formed hydrogel network. The characterization of developed biodegradable hydrogels were studied using fourier transforms infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The biodegradable gold nanoparticle composite hydrogels developed were tested for antibacterial properties. The results indicate that these biodegradable gold nanocomposite hydrogels can be used as potential candidates for antibacterial applications.

Iota-Carrageenan-based biodegradable Ag0 nanocomposite hydrogels for the inactivation of bacteria

In this paper, we report the synthesis and characterization of Iota-Carrageenan based on a novel biodegradable silver nanocomposite hydrogels. The aim of study was to investigate whether these hydrogels have the potential to be used in bacterial inactivation applications. Biodegradable silver nanocomposite hydrogels were prepared by a green process using acrylamide (AM) with I-Carrageenan (IC). The silver nanoparticles were prepared as silver colloid by reducing AgNO3 with leaf extracts of Azadirachta indica (neem leaf) that (Ag(0)) formed the hydrogel network. The formation of biodegradable silver nanoparticles in the hydrogels was characterized using UV-vis spectroscopy, thermo gravimetrical analysis, X-ray diffractometry studies, scanning electron microscopy and transmission electron microscopy studies. In addition, swelling behavior and degradation properties were systematically investigated. Furthermore, the biodegradable silver nanoparticle composite hydrogels developed were tested for antibacterial activities. The antibacterial activity of the biodegradable silver nanocomposite hydrogels was studied by inhibition zone method against Bacillus and Escherichia coli, which suggested that the silver nanocomposite hydrogels developed were effective as potential candidates for antimicrobial applications. Therefore, the inorganic biodegradable hydrogels developed can be used effectively for biomedical application.

Microbial resistant nanocurcumin-gelatin-cellulose fibers for advanced medical applications

Curcumin, a greatly potent, non-toxic and naturally existing bioactive material in turmeric is widely employed to develop biomedical functional materials due to its environmental friendly nature. In general, curcumin functional materials were prepared by administrating non-aqueous solvents as a dissolving medium for curcumin. These non-aqueous solvents cause adverse effects for the environment and humans. However, if the curcumin functional materials are developed based on aqueous solution then the adverse effects can be eliminated. In view of this, for the first time aqueous based nanocurcumin (nanoparticles of curcumin) impregnated gelatin cellulose fibers (NCGCFs) were developed by a green process. The required nanocurcumin was prepared by ultrasonication process. Transmission electron microscopy showed the sizes of nanocurcumin exist in the range ∼2 to 15 nm. Nuclear magnetic resonance spectra showed no structural modification of nanocurcumin to that of curcumin. The developed fibres were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, thermal analysis and swelling studies. Cumulative releasing studies showed slow and sustained releasing patterns for NCGCFs. A comparative antimicrobial study was performed for nanocurcumin impregnated gelatin cellulose fibres (NCGCFs) and curcumin impregnated gelatin cellulose fibres (CGCFs) against E. coli and S. aureus. The results indicated the superior performance of NCGCFs over CGCFs. Hence, NCGCFs prepared completely from naturally available materials can be considered as a novel kind of functional materials for wound dressing and antimicrobial applications.

Antibacterial nanocomposite hydrogels for superior biomedical applications: a Facile eco-friendly approach

In this scientific paper, we report a facile and eco-friendly fabrication of antibacterial nanocomposite hydrogels of Au-core Ag-shell nanoparticles, embedded within Carbopol® 980 NF/Noveon® AA-1 polycarbophil acrylic acid polymeric matrix. The aim of the study was to investigate whether these nanocomposite hydrogels have the potential to be used for bacterial inactivation applications. The key feature was that, unlike the use of chemical reductants, auxiliary stabilizers and specialized expensive equipment, the Au-core Ag-shell nanoparticles (∼15 ± 3 nm) were synthesized utilizing aqueous mint leaf extracts. The developed hydrogels were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy/energy-dispersive spectroscopy and thermogravimetric analysis. Swelling studies were performed in phosphate buffered saline (pH 7.4) solution. A sustained antibacterial study against E. coli (G−) and B. subtilis (G+) showed their excellent antibacterial efficiency, which suggested that the developed hydrogels are potential candidates for a wide range of biomedical applications.

Development of Sodium Carboxymethyl Cellulose-based Poly(acrylamide-co-2acrylamido-2-methyl-1-propane sulfonic acid) Hydrogels for In Vitro Drug Release Studies of Ranitidine Hydrochloride an Anti-ulcer Drug

The formation of sodium carboxymethyl cellulose (SCMC) based semi-interpenetrating networks (semi-IPN) with poly(acylamide-co-2-acrylamido-2-methy-l-propanesulfonic-acid) hydrogels. The hydrogels were prepared by free-radical polymerization using redox initiator. The characterizations of hydrogels were done by swelling experiments, FTIR spectroscopy and DSC analysis. Morphology of the samples were examined by SEM. Experimental results indicate that the semi-IPN hydrogel containing 0.10 g of SCMC and 5.829 mM of AMPS, shows the highest swelling capacity (64.83 g/g). The swelling behavior of the semi-IPN hydrogel (AS5) was studied in different pH solutions. The ranitidine hydrochloride drug loading and release of the semi-IPN hydrogels were studied by using a UV spectrophotometer.

Development of microbial resistant thermosensitive Ag nanocomposite (gelatin) hydrogels via green process

In this investigation, an ecofriendly method for the synthesis of silver nanoparticles (AgNPs) using biodegradable gelatin as a stabilizing agent is reported. Here, we prepared thermosensitive silver nanocomposite hydrogels composed of gelatin and N-isopropylacrylamide. In this green process AgNPs were formed from Ag(+) ions and reduced with leaf [Azadirachta indica (neem leaf)] extracts, resulting in a hydrogel network. The Ag(0) nanoparticles affect the hydrogel strength and improved the biological activity (inactivation effect of bacteria) of the biodegradable hydrogels. The resulted hydrogel structure, morphology, thermal, swelling behavior, degradation, and antibacterial properties were systematically investigated. The biodegradable thermosensitive silver nanocomposite hydrogels developed were tested for antibacterial activities. The results indicate that these biodegradable silver nanocomposite hydrogels are suitable potential candidates for antibacterial applications.

Synthesis of Surfactant-Modified Poly (Acrylamide-co-Potassium Acrylate) Hydrogels and Its in vitro Release Studies

In present investigation, a series of hydrogels, composed with Surfactant and poly(Acrylamide-co-Potassium acrylate), using Ammonium per sulfate(APS)/N,N,N 1 , N 1 -tetram ethylethylene diamine (TMEDA) initiating system and N,N 1-methylenebisacrlyamide (MBA) as crosslinker. The prepared hydrogel was characterized by using Fourier transform infrared spectroscopy (FTIR), Thermo gravimetric analysis (TGA), Scanning electron microscopy (SEM). The controlled release characteristics of the matrices for Triprolidene hydrochloride (TH) were investigated in pH 7.4 media. Drug was released in a controlled manner up to 1400 min.

Synthesis and Properties of Poly(AAm‐KMA‐MA) Hydrogels

In this investigation, poly(acrylamide‐co‐potassium methacrylate‐co‐maleic acid) hydrogels, poly(AAm‐KMA‐MA) were synthesized by redox copolymerization in aqueous solution. The effect of reaction parameters, such as concentration of maleic acid, crosslinking agent, initiator and activator, on the swelling behavior was investigated in detail. The swelling/diffusion characteristics were also evaluated for 1,4‐butanediol diacrylate (BDDA) and 1,2‐ethyleneglycol dimethacrylate (EGDMA) crosslinked hydrogels having different amounts of maleic acid. The results indicate that the water diffusion of hydrogels was of a non‐Fickian type. The hydrogels were characterized by IR spectroscopy and thermogravimetric analysis (TGA). Their surface characteristics were observed by using scanning electron microscopy (SEM). Furthermore, their swelling phenomena in different pH and salt solutions and simulated biological fluids was also studied.In this investigation, poly(acrylamide‐co‐potassium methacrylate‐co‐maleic acid) hydrogels, poly(AAm‐KMA‐MA) were synthesized by redox copolymerization in aqueous solution. The effect of reaction parameters, such as concentration of maleic acid, crosslinking agent, initiator and activator, on the swelling behavior was investigated in detail. The swelling/diffusion characteristics were also evaluated for 1,4‐butanediol diacrylate (BDDA) and 1,2‐ethyleneglycol dimethacrylate (EGDMA) crosslinked hydrogels having different amounts of maleic acid. The results indicate that the water diffusion of hydrogels was of a non‐Fickian type. The hydrogels were characterized by IR spectroscopy and thermogravimetric analysis (TGA). Their surface characteristics were observed by using scanning electron microscopy (SEM). Furthermore, their swelling phenomena in different pH and salt solutions and simulated biological fluids was also studied.

A New Series of Two-Ring-Based Side Chain Liquid Crystalline Polymers: Synthesis and Mesophase Characterization

A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings and an ester linking unit. All the polymers were characterised by hot-stage polarising optical microscopy, differential scanning calorimetry, variable temperature X-ray diffraction, thermogravimetric analysis, and gel permeation chromatography. The polymers were found to be liquid crystalline. The nematic and smectic A (SA) phases were observed for the homologues with short-terminal chains (C2 and C6), whereas the homologues with longer chains (C8 to C12) exhibited a smectic C phase. The thermal stability of the polymers was found to be in the range of 293 to 326 0 C and the molecular weights of the polymers were found to vary from 6_10 3 to 1.3_10 4 .