Drug functionalized microbial polysaccharide based nanofibers as transdermal substitute.

In order to promote the natural healing process, drug-functionalized nanofibrous transdermal substitute was fabricated using gellan as chief polymer and polyvinyl alcohol (PVA) as supporting polymer via electrospinning technique. These fabricated nanofibers physiochemically mimic the extracellular matrix (ECM) which supports the cell growth. For neo-tissue regeneration in a sterilized environment, amoxicillin (Amx) was entrapped within these nanofibers. Entrapment of Amx in the nanofibers was confirmed by FESEM, FTIR, XRD and TG analysis. In vitro cell culture studies revealed that the fabricated non-cytotoxic nanofibers promoted enhance cell adherence and proliferation of human keratinocytes. A preliminary in vivo study performed on rat model for full thickness skin excision wound demonstrated the prompt re-epithelialization in early phase and quicker collagen deposition in later phases of wound healing in case of Amx-functionalized gellan/PVA nanofibers. Data collectively confirmed the potential usage of gellan based electrospun nanofibers as transdermal substitute for faster skin restoration.

Production and characterization of Komagataeibacter xylinus SGP8 nanocellulose and its calcite based composite for removal of Cd ions.

In the present study, fermentative production of bacterial nanocellulose (BNC) by using Komagataeibacter xylinus strain SGP8 and characterization of nanocellulose is presented. The bacterium was able to produce 1.82 g L-1 of cellulose in the form of pellicle in standard Hestrin-Schramn (HS) medium. The morpho-structural characterization of the BNC using scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies, respectively revealed nanofibrillar structure and high crystallinity index (~86%). The thermogravimetric analysis (TGA) showed the stability of BNC up to 280 °C, further rise in temperature to 350 °C results in depolymerization of the sample. In order to show the applicability of produced BNC, it was modified first using calcite (CaCO3) and thereafter characterized using SEM, XRD, FTIR, and TGA studies. The BNC-CaCO3 composites as a sorbent resulted in >99% removal of initial 10 mg L-1 of Cd (II) at pH 5, 7 and 9 after 12 h of treatment. Moreover, the composite was also found to be competent in removing high concentrations of Cd (25 and 50 mg L-1) from the solution (69-70%). Overall, the above results suggest that cellulose produced by K. xylinus strain SGP8 showed excellent material properties, and modified BNC (BNC-CaCO3 composite) could effectively be used for remediation of toxic levels of Cd from the contaminated system.

A novel gellan-PVA nanofibrous scaffold for skin tissue regeneration: Fabrication and characterization.

In this investigation, we have introduced novel electrospun gellan based nanofibers as a hydrophilic scaffolding material for skin tissue regeneration. These nanofibers were fabricated using a blend mixture of gellan with polyvinyl alcohol (PVA). PVA reduced the repulsive force of resulting solution and lead to formation of uniform fibers with improved nanostructure. Field emission scanning electron microscopy (FESEM) confirmed the average diameter of nanofibers down to 50 nm. The infrared spectra (IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis evaluated the crosslinking, thermal stability and highly crystalline nature of gellan-PVA nanofibers, respectively. Furthermore, the cell culture studies using human dermal fibroblast (3T3L1) cells established that these gellan based nanofibrous scaffold could induce improved cell adhesion and enhanced cell growth than conventionally proposed gellan based hydrogels and dry films. Importantly, the nanofibrous scaffold are biodegradable and could be potentially used as a temporary substrate/or biomedical graft to induce skin tissue regeneration.

Process optimization for fabrication of gellan based electrospun nanofibers.

In this investigation, the nanofiber formation ability of gellan, a FDA approved low cost natural polysaccharide, has been achieved for the first time using electrospinning technique. The gellan based ultrafine nanofibers were fabricated by using a blend mixture of gellan with another biodegradable polymer polyvinyl alcohol (PVA). The morphology of resulting gellan-PVA nanofibers was analyzed using field emission scanning electron microscopy (FESEM). The mass ratio of 50:50 for gellan:PVA was recorded as an optimum solution ratio to obtain uniform bead free nanofibers with an average diameter of 40 ± 15.8 nm. Data depicted that among different parameters evaluated, viscosity and the mass ratio of gellan:PVA were the key parameters that influence the nanofiber morphology and diameter.

Bleach enhancement of mixed wood pulp by xylanase-laccase concoction derived through co-culture strategy.

Mixed enzyme preparation having both xylanase and laccase activity was evaluated for its bleach enhancing ability of mixed wood pulp. The enzyme was produced through co-cultivation of mutant Penicillium oxalicum SAU(E)-3.510 and Pleurotus ostreatus MTCC 1804 under solid-state fermentation. Bleaching of pulp with mixed enzyme had resulted into a notable decrease in kappa number and increased brightness as compared to xylanase alone. Analysis of bleaching conditions had denoted that 8 IU g(-1) of mixed enzyme preparation (xylanase/laccase, 22:1) had led into maximal removal of lignin from pulp when bleaching was performed at 10% pulp consistency (55 degrees C, pH 9.0) for 3 h. An overall improvement of 21%, 8%, 3%, and 5% respectively in kappa number, brightness, yellowness, and viscosity of pulp was achieved under derived bleaching conditions. Process of enzymatic bleaching was further ascertained by analyzing the changes occurring in polysaccharide and lignin by HPLC and FTIR. The UV absorption spectrum of the compounds released during enzymatic treatment had denoted a characteristic peak at 280 nm, indicating the presence of lignin in released coloring matter. The changes in fiber morphology following enzymatic delignification were studied by scanning electron microscopy.