Green synthesis of cadmium oxide decorated reduced graphene oxide nanocomposites and its electrical and antibacterial properties.

A green, efficient synthesis of cadmium oxide decorated reduced graphene oxide nanocomposites (RGO/CdO) was prepared by one-step co-precipitation and hydrothermal method. Crystalline nature of the nanocomposites was characterized by X-ray diffraction analysis. To evaluate the structural morphology and particle size, high resolution transmission electron microscopy were used. X-ray photoelectron spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy techniques were employed to establish chemical structure of the nanocomposites and Atomic Force Microscopy was done to measure the thickness. The optical properties were evaluated by UV-visible absorption spectroscopy. Thermo-gravimetric analysis, BET surface area and zeta potential measurements were carried out to study the thermal and surface characteristics. The CdO nano-particles (NPs) decorated on RGO sheets exhibit better electrical conductivity compared to RGO. The antibacterial activity of the nanocomposites has also been monitored in different culture media imparting good potentiality than RGO.

Effect of cellulose nanocrystals on the performance of drug loaded in situ gelling thermo-responsive ophthalmic formulations.

Triblock poloxamer copolymer (PM) has been extensively utilized to deliver various ophthalmic pharmaceutical compounds. The aim of efficient ophthalmic drug delivery strategy is to attain the longer precorneal resident time and good bioavailability of drugs. In this pursuit, the influence of cellulose nanocrystals (CNC) on the in situ gelation behavior of PM and in vitro release of pilocarpine hydrochloride from the nanocomposites formulations was studied. The critical concentration of gelation of PM being 18% (wt/v) was dropped to 16.6% (wt/v) by the addition of a very low percentage of CNC. The reinforcing nature of CNC via H-bonding in the in situ nanocomposite gel also led to an increase in gel strength along with the sustained release of loaded drugs when compared with the pure PM gel. All formulations revealed that the drug release mechanism is controlled by the Fickian diffusion. Thus, the CNC has a significant effect on the gelation behavior, gel strength, and drug release kinetics of PM-CNC formulations.

Development of an auto-phase separable and reusable graphene oxide-potato starch based cross-linked bio-composite adsorbent for removal of methylene blue dye.

In this work, we report the development of a cross-linked bio-composite consisting of graphene oxide, potato starch, cross-linker glutaraldehyde and its application to adsorption of the industrial dye, methylene blue, from aqueous solution. The inexpensiveness, non-hazardous nature and easy bio-degradability are the major reasons for the selection of starch material as one of the components of the bio-composite. The bio-composite has been characterized by FTIR, SEM, XRD, particle size and zeta potential analysis. The FTIR analysis reveals the nature of the binding sites and surface morphology of the bio-composite can be understood through SEM. The auto-phase separability of the adsorbent i.e., the precipitation of the adsorbent without any mechanical means is another factor which makes this particular material very attractive as an adsorbent. Parameters like adsorbent dosage, pH, temperature, rotation speed and salt concentration have been varied to find out the suitable dye adsorption conditions. Furthermore, the time dependence of adsorption process has been analyzed using pseudo-first and pseudo-second order kinetics. The adsorption isotherms have been constructed to suggest convincing mechanistic pathway for this adsorption process. Finally, desorption studies have been successfully performed in 3 cycles, establishing the reusability of the material, which should allow the adsorbent to be economically promising for practical application in wastewater treatment.

Development of active packaging material based on cellulose acetate butyrate/polyethylene glycol/aryl ammonium cation modified clay.

Active packaging is one of the interesting concepts in food industry which extend the shelf-life of the food products. The purpose of this work was to develop nontoxic antimicrobial nanocomposite films. Benzyltrimethylammonium chloride modified montmorillonite (BMMT) were used as nano-filler and the prepared BMMT was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis. Polyethylene glycol (PEG) plasticized cellulose acetate butyrate (CAB) films with different ratios of PEG and CAB was prepared and it was found that the 20 wt% PEG in CAB matrix (CBP20) gave optimal results in terms of mechanical properties. BMMT was mixed with CBP20 in different proportions to prepare nanocomposites. 3 wt% BMMT loaded nanocomposite gave best in terms of the barrier and mechanical properties. The storage modulus, thermal stability, glass transition, and melting temperature of the nanocomposites increased with the loading of 1, 3, and 5 wt% of BMMT. Furthermore, these nanocomposites showed nontoxic and antimicrobial behavior.

Studies on methylcellulose/pectin/montmorillonite nanocomposite films and their application possibilities.

Films based on methylcellulose (MC) and pectin (PEC) of different ratios were prepared. MC/PEC (90:10) (MP10) gave the best results in terms of mechanical properties. Sodium montmorillonite (MMT) (1, 3 and 5 wt%) was incorporated in the MP10 matrix. The resulting films were characterized by X-ray diffraction and transmission electron microscopy, and it was found that nanocomposites were intercalated in nature. Mechanical studies established that addition of 3 wt% MMT gave best results in terms of mechanical properties. However, thermo-gravimetric and dynamic mechanical analysis proved that decomposition and glass transition temperature increased with increasing MMT concentration from 1 to 5 wt%. It was also observed that moisture absorption and water vapor permeability studies gave best result in the case of 3 wt% MMT. Optical clarity of the nanocomposite films was not much affected with loading of MMT. In vitro drug release studies showed that MC/PEC/MMT based films can be used for controlled transdermal drug delivery applications.

Taro corms mucilage/HPMC based transdermal patch: an efficient device for delivery of diltiazem hydrochloride.

The aim of this work is to examine the effectiveness of mucilage/hydroxypropylmethylcellulose (HPMC) based transdermal patch (matrix type) as a drug delivery device. We have successfully extracted mucilage from Colocasia esculenta (Taro) corms and prepared diltiazem hydrochloride incorporated mucilage/HPMC based transdermal patches using various wt% of mucilage by the solvent evaporation technique. Characterization of both mucilage and transdermal patches has been done by several techniques such as Molisch's test, organoleptic evaluation of mucilage, mechanical, morphological and thermal analysis of transdermal patches. Skin irritation test is studied on hairless Albino rat skin showing that transdermal patches are apparently free of potentially hazardous skin irritation. Fourier transform infrared analysis shows that there is no interaction between drug, mucilage and HPMC while scanning electron microscopy shows the surface morphology of transdermal patches. In vitro drug release time of mucilage-HPMC based transdermal patches is prolonged with increasing mucilage concentration in the formulation.