N. Narayana Reddy

Fabrication of porous chitosan films impregnated with silver nanoparticles: A facile approach for superior antibacterial application

The present investigation involves the synthesis of porous chitosan-silver nanocomposite films in view of their increasing areas of application in wound dressing, antibacterial application, and water purification. The entire process consists of three-steps including silver ion-poly(ethylene glycol) matrix preparation, addition of chitosan matrix, and removal of poly(ethylene glycol) from the film matrix. Uniform porous and brown colour chitosan films impregnated with silver nanoparticles (AgNPs) were successfully fabricated by this facile approach. Both, poly(ethylene glycol) (PEG) and chitosan (CS) played vital roles in the reduction of metal ions into nanoparticles (NPs) as well as provided good stability to the formed nanoparticles. The developed porous chitosan-silver nanocomposite (PCSSNC) films were characterized by UV-vis and FTIR spectroscopy, and thermogravimetric analysis for the confirmation of nanoparticles formation. The morphology of silver nanoparticles in nanocomposite films was tested by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The embedded AgNPs were clearly observed throughout the film in SEM and the extracted AgNPs from the porous chitosan-silver nanocomposite showed approximately 12nm in TEM. Improved mechanical properties were observed for porous chitosan-silver nanocomposite than for chitosan blend (CSB) and chitosan-silver nanocomposite (CSSNC) films. Further, the examined antibacterial activity results of these films revealed that porous chitosan-silver nanocomposite films exhibited superior inhibition.

Synthesis and Characterizations of Macroporous Poly(acrylamide-2-acrylamido-2-methyl-1-propanesulfonic acid) Hydrogels for In Vitro Drug Release of Ranitidine Hydrochloride

Macroporous hydrogels were prepared with acrylamide (AM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as well as with anhydrous dextrose (AD) as porogen by crosslinking with N,N1-methylenebisacrylamide (MBA). The chemical structure of hydrogels is characterized by Fourier transform infrared (FTIR) spectroscopy. Morphological studies done by scanning electron microscopy (SEM) showed the macroporous nature of the hydrogels. Swelling studies of hydrogels were done in distilled water, in aqueous NaCl solution and in different pH solutions. In addition, drug release studies of selected macroporous hydrogels (DAMPS1, DAMPS4, DAMPSM1 and DAMPSM3) are also investigated.

Poly(acrylamide-chitosan) Hydrogels: Interaction with Surfactants

Semi-interpenetrating hydrogels were prepared from hydrophilic acrylamide and cationic natural biopolymer chitosan, N,N1-methylenebisacrylamide and water-soluble redox initiating system (ammonium persulfate/N,N,N1,N1-tetramethylethylenediamine). The interaction of these hydrogels with different surfactants such as sodiumdodecylsulphate (SDS, anionic), N-cetyl N,N,N-trimethyl ammonium bromide (CTA, cationic) and Tween20 (T20 non-ionic) was studied. The chemical structure of the hydrogels treated with surfactant was characterized by FTIR spectroscopy and the morphology of hydrogels was characterized by scanning electron microscopy (SEM). The thermal properties of surfactant-treated hydrogels were evaluated by TGA analysis.

Surfactant-Modified Poly(acrylamide-co-acrylamido propane sulphonic acid) Hydrogels

Recent advances in drug delivery have been directed towards the design of a number of intelligent systems for the treatment of various diseases. In this regard, we developed novel surfactant-modified hydrogels which are synthesized from acrylamide (AM) and acrylamido propane sulphonic acid (AMPS), in the presence of a surfactant (Latemul PD-104) using ammonium persulfate/N,N,N′,N′–tetramethylethylene diamine (APS)/(TMEDA) as an initiating system and N,N′-methylenebisacrlyamide (MBA) as a crosslinker. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The variation in the hydrogel networks formation employing different levels of synthetic parameters was verified by swelling studies. Influences of salt, biological fluids, and buffer solutions on the developed systems were also investigated. It was found that, compared to PAM hydrogel, all the surfactant-modified hydrogels were responsive towards salt concentration and pH. A robust drug release behavior was observed from surfactant-modified hydrogel systems.