Sustainable removal of hexavalent chromium using graphene oxide - Iron oxide reinforced pectin/polyvinyl alcohol magnetic gel beads.

The study investigated removal of hexavalent chromium Cr (VI) from aqueous solution using graphene oxide­iron oxide reinforced pectin/polyvinyl alcohol magnetic gel beads prepared through co-precipitation and freeze-drying technique. Scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, N2 adsorption-desorption isotherm, and zeta potential are used for characterization. The surface area of magnetic gel beads calculated by BET method was determined to be 100.95 m2/g, significantly higher than that of GO and GO-Fe3O4. The optimum removal efficiency of GO-Fe3O4/Pec/PVA was assessed by batch method at variables such as pH(1-6), adsorption time(0-180 min), and temperature(25-35 °C). Accordingly, 0.2 g GO-Fe3O4/Pec/PVA dose, pH 2, contact time: 120 min at 25 °C were found to be the optimal conditions, and maximum adsorption capacity of GO, GO-Fe3O4 and GO-Fe3O4/Pec/PVA toward Cr(VI) removal was found to be 39.5, 62.5 and 78.55 mg g-1, respectively. Kinetic and isotherm studies indicate adsorption data follow pseudo-second-order kinetic and Langmuir isotherm models. Thermodynamic studies showed adsorption capacities of adsorbents decreased when temperature increased which indicated adsorption for Cr (VI) was an exothermic process. The activation energies were found to be 34.92, 26.57, and 35.23 KJ mol-1 for GO, GO-Fe3O4, and GO-Fe3O4/Pec/PVA, respectively, which illustrated adsorption of Cr(VI) onto the surface of adsorbents was a physical process. The beads exhibit excellent recoverability and reusability over five cycles. Overall, GO-Fe3O4/Pec/PVA demonstrates exceptional adsorption properties and can serve as an efficient, stable, less toxic, and magnetically separable adsorbent for removal of Cr(VI) from aqueous solution.

In vitro cytocompatibility assessment and antibacterial effects of quercetin encapsulated alginate/chitosan nanoparticle.

The present work aims at evaluating the in vitro biocompatibility, antibacterial activity and antioxidant capacity of the fabricated and optimized Alginate/Chitosan nanoparticles (ALG/CSNPs) and quercetin loaded Alginate/Chitosan nanoparticles (Q-ALG/CSNPs) with an improved biological efficacy on the hydrophobic flavonoid.The physicochemical properties were determined by TEM and FTIR analysis. The nanoparticles evaluated for the encapsulation of quercetin exerted % encapsulation efficiency (EE) that varied between 76 and 82.4 % and loading capacity (LC) from 31 to 46.5 %. Potential cytotoxicity of the ALG/CSNPs and Q-ALG/CSNPs upon L929 fibroblast cell line was evaluated by MTT reduction Assay and expressed as % cell viability. The in vitro antibacterial property was studied by well diffusion method against gram-positive bacteria Staphylococcus aureus (ATCC 25925) and gram-negative bacteria Escherichia coli (ATCC 25923). The inhibitory efficacy by scavenging free radical intermediates was evaluated by 1,1, diphenyl 2-picrylhydrazyl (DPPH) assay. The results of in vitro cytotoxicity showed biocompatibility towards L929 cells. Quercetin loaded Alginate/Chitosan nanoparticles inhibited the growth of microorganisms than pure quercetin. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging results have shown a high level of antioxidant property for encapsulated Quercetin in Alginate/Chitosan nanoparticles compared to free Quercetin. The findings of our study suggest that the developed ALG/CSNPs and Q-ALG/CSNPs possess the prerequisites and be proposed as a suitable system for delivering quercetin with enhanced therapeutic effectuality.

Development of Biomimetic Hybrid Porous Scaffold of Chitosan/Polyvinyl Alcohol/Carboxymethyl Cellulose by Freeze-Dried and Salt Leached Technique.

Freeze drying and salt leaching methods were applied to fabricate Chitosan/Poly(vinyl alcohol)/Carboxymethyl cellulose (CPCMC) biomimetic porous scaffolds for soft tissue engineering. The properties of these scaffolds were investigated and compared to those by freeze drying and salt leaching methods respectively. The salt-leached CS/PVA/CMC scaffolds were easily formed into desired shapes with a uniformly distributed and interconnected pore structure with an average pore size. The mechanical strength of the scaffolds increased with the porosity, and were easily modulated by the addition of carboxymethyl cellulose. The morphology of the porous scaffolds observed using a SEM exhibited good porosity and interconnectivity of pores. MTT assay using L929 fibroblast cells demonstrated that the cell viability of the porous scaffold was good. Scaffolds prepared by salt leached method show larger swelling capacity, and mechanical strength, potent antibacterial activity and more cell viability than freeze dried method. It is found that salt leaching method has distinguished characteristics of simple, efficient, feasible and less economic than freeze dried scaffolds.

Synthesis and characterization of chitosan-PVP-nanocellulose composites for in-vitro wound dressing application.

Biocompatible Chitosan/Poly (vinyl pyrrolidone)/Nanocellulose (CPN) composites were successfully prepared by solution casting method. The prepared bionanocomposites were characterized by Transmission electron microscopy (TEM), Thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectra. TEM images revealed the average particle size of the nanocellulose is 6.1nm. Thermogravimetric analysis indicated that the thermal stability of the composites was decreased with increasing concentration of nanocellulose. The CPN composites were characterized for physical properties like Thickness, Barrier properties and mechanical testing. Water vapor and oxygen permeability evaluations indicated that CPN composite could maintain a moist environment over wound bed. The nanocomposite showed enhanced swelling, blood compatibility and antibacterial activity. Cytotoxicity of the composite has been analyzed in normal mouse embryonic fibroblast cells. The results have shown the CPN3% composite shows a high level of antibacterial property when compared to the other composites. The biological study suggests that CPN3% composite may be a potential candidate as a wound healing material for biomedical application.