Rashid Masood

Production of rhamnolipid surfactant and its application in bioscouring of cotton fabric

In the present study, a biosurfactant was synthesized by using a bacterial strain of Pseudomonas aeruginosa in minimal media provided with n-heptadecane as sole carbon source under shake-flask conditions. The biosurfactant was isolated (by acid precipitation, solvent extraction, and rotary evaporation), purified (by column chromatography and TLC), identified (by FAB-MS, FTIR, and 1D-(1)H NMR), and chemo-physical characterized (by tensiometry). Two principal rhamnolipid congeners were identified as dirhamnolipid RRC10C10 and monorhamnolipid RC10C10 with a CMC of 50mg/L. The biosurfactant, hence produced, was applied in sole and in combination with pectinase in scouring of cotton fabric in contrast to conventional scouring agents of NaOH and anionic surfactant SDS. The scoured cotton fabric was investigated for its weight loss, residual oil and grease, wettability, whiteness, and tensile strength. The results were compared both for conventional and biological approaches. The scouring with biosurfactant plus pectinase was equivalent to or better in efficiency than conventional alkaline scouring. The former process is additionally environmentally friendly and bio-compatible. Scanning electron microscopy of cotton fabric showed that the alkaline scouring deteriorates the fabric texture whereas bioscouring with biosurfactant plus pectinase gently removes hydrophobic impurities from the cotton fabric.

A new carbohydrate-based wound dressing fibre with superior absorption and antimicrobial potency.

Heavily exudating wounds can lead to infection and unnecessary trauma if they are not adequately managed. Manufacturers involved in production and marketing of high absorption silver dressings, besides emphasising high absorptions of their dressings are keen to highlight potent antimicrobial abilities of their products against all kinds of pathogens including MRSA. However, there are little or no credible reports on minimal but potent quantities of silver needed in a dressing to eliminate bacteria spread and growth or how effectively the silver within a dressing is released over time. This paper introduces a new hybrid biomaterial fibre made from polysaccharide-based polymers with inbuilt ability to gel and absorb large quantities of pseudo exudates. Furthermore, it will be reported that the new fibre carries up to six times less silver than it is conventionally used in silver dressings and displays a very slow rate of release whilst maintaining full potency over time against known Gram positive, Gram negative micro-organisms including MRSA. The paper concludes that the developed hybrid fibre has long lasting antimicrobial and gelling properties comparable, if not better, than Acticoat AA and Aquacel Ag, two commercially available silver dressings.

Antimicrobial Properties of Alginate-Chitosan (Alchite) Fibers Developed for Wound Care Applications

Alginate fibers are well established as primary wound dressings, given their well-known sodium/calcium ion exchange ability at the wound surface coupled with their good liquid absorption characteristics. Chitosan, the deacetylated form of chitin is also well known for its hemostatic, antimicrobial, and wound-healing properties. Unique combination of these polysaccharides to form a new generic fiber, known as alchite fibers, has been developed in an earlier work. This article reports on the antimicrobial properties of a range of alchite fibers produced from four different types of hydrolyzed chitosans and two brands of sodium alginate. The article discusses different methods of antimicrobial detection including: submerged fiber technique, zone of inhibition, dilution plating, and spectrophotometric analysis at 600 nm when tested against common skin microflora, i.e., Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus. This study concludes that while most of the alchite fiber samples have certain degree of antimicrobial properties, some have higher antimicrobial properties than others. The study has also shown that quantitative presence of chitosan within an alchite fiber may not necessarily be the reason for good antimicrobial properties. Factors such as chitosan source, degree of deacetylation, molecular weight, and action of hydrolysis may also affect antimicrobial properties. These findings are most important in endorsing the development of the alchite fibers for wound dressings.

Development of slow release silver-containing biomaterial for wound care applications

Silver-containing wound dressings are now commonly available with much publicised claims of antimicrobial activities against all kinds of pathogens including methicillin-resistant Staphylococcus aureus (MRSA). However, there are little or no credible reports on the control release agents for the minimum potent quantities of silver needed in dressings for antimicrobial purposes over time. This paper introduces a new biomaterial fibre made from natural polymers with an inbuilt ability to gel and absorb large quantities of pseudo exudates. Furthermore, the new fibre carries up to six times less silver than it is conventionally used in silver dressings and displays a very slow rate of release whilst maintaining full potency over time against known microorganisms including methicillin-resistant S. aureus. The paper concludes that the developed fibre has long-lasting antimicrobial and gelling properties comparable, if not better, than Acticoat AA and Aquacel Ag, two commercially available silver dressings.

In situ development and application of natural coatings on non-absorbable sutures to reduce incision site infections

OBJECTIVE The purpose of the study was the development of a suture line that has antibacterial properties and reduces the chance of wound infection thus facilitating the healing process. METHOD Hydrolysed chitosan, turmeric powder and clove oil were used in different proportions to formulate antimicrobial coating for the polyethylene terephthalate (PET) and polyamide (Nylon 6) threads. The threads were coated using a lab-scale yarn sizing machine. Tensile, and knot strength of the coated sutures were measured. As was the antimicrobial action of Staphylococcus aureus strain ATCC29213. RESULTS The results show that coatings have slightly improved the tensile and knot strength properties of these sutures. The coated sutures also have satisfactory microbial inhibition against Staphylococcus aureus. CONCLUSION The coating slightly improved the tensile strength of the sutures. However, the knot is the weakest part of the suture strand. All the formulations of the coating have shown satisfactory antimicrobial activity against Gram-positive Staphylococcus aureus bacteria. We conclude that application of natural coatings on non-absorbable sutures can be useful to reduce the incisions and wound site infections.

Development and evaluation of a controlled drug delivery wound dressing based on polymeric porous microspheres

The aim of the present work was to develop and evaluate a controlled drug delivery wound dressing based on polymeric porous microspheres, which are also termed as microsponge drug delivery system. For this purpose, turmeric (drug)-based polymeric porous microspheres formulations were developed by quasi-emulsion solvent diffusion method. The production yields, actual drug content, drug entrapment efficiency, particle size, formulation of the material, and in vitro release were studied. On the basis of maximum drug released, a formulation was selected to incorporate into wound dressings with the help of a binder by spraying technique. Finally, the selected formulation and samples of wound dressings containing microsponges were subjected to scanning electron microscopy and drug release analyses. The result of in vitro release shows that microsponge drug delivery system is a versatile tool that has a potential to convert any wound dressing into a controlled drug delivery wound dressing.

Development and characterization of alginate-chitosan-hyaluronic acid (ACH) composite fibers for medical applications

Natural materials and plants have a long history of medical applications due to their broad range of favorable biological functions including biocompatibility, anti-bacterial, anti-oxidant and anti-inflammatory properties. Main objective of this study was to develop alginate-chitosan-hyaluronic acid (ACH) composite fibers with controlled drug release, and liquid retention properties for better moist wound healing. The dope comprising sodium alginate was extruded into calcium chloride (CaC12) coagulation bath. The developed calcium alginate fibers were then passed through a bath containing hydrolyzed chitosan and dip coated with hyaluronic acid for 24 hours. The resulting ACH composite fibers were then rinsed with deionized water and dried using acetone. These fibers were tested for tensile properties, % swelling, liquid absorption (g/g) and controlled drug release. The results concluded that ACH composite fibers can be produced by wet spinning and have adequate tensile properties, high % swelling, liquid absorption (g/g) and controlled release of hyaluronic acid for improved wound healing.

Development of tri-component antibacterial hybrid fibres for potential use in wound care

OBJECTIVE Tri-component antibacterial psyllium-alginate-chitosan fibres were developed and their properties were studied with reference to their application in health-care. METHOD Psyllium was co-extruded with sodium alginate as a carrier into a coagulation bath containing calcium chloride and hydrolysed chitosan. Different concentrations of the hydrolysed chitosan were used and an in vitro assessment of antibacterial activity of the produced fibres was carried out against the known pathogens of Staphylococcus aureus and Escherichia coli. The effect of hydrolysed chitosan bath composition on physical and mechanical properties of produced fibres was also examined. RESULTS Chitosan-containing fibres demonstrated a 70-130% thicker dry diameter than the control fibre (F1). The linear density of the fibre increased from 6.8 to 10 tex as the chitosan concentration increased from 10g/l to 30g/l (fibre type F1 to F4). With the addition of hydrolysed chitosan, distilled water absorption was increased while the saline and solution-A (0.83% w/v NaCl and 0.03% w/v CaCl2) absorption decreased. The percentage strain of hybrid fibres was lower than the control fibre due to the inclusion of hydrolysed chitosan. At lower viscosities of the hydrolysed chitosan bath, the fibres were much stiffer due to better penetration of the hydrolysed chitosan. Similarly, at lower viscosities, the tenacities of the hybrid fibres were higher than the control fibre. The hydrolysed chitosan-treated fibres were more effective against Staphylococcus aureus than the Escherichia coli, and the antibacterial activity increased with the decrease in viscosity of the hydrolysed chitosan bath. CONCLUSION We developed novel PAC fibres. Antibacterial testing showed that hydrolysed chitosan was more effective against Gram-positive bacteria than Gram-negative bacteria.

Linear and crosslinked Polyurethanes based catalysts for reduction of methylene blue

The large amount of synthetic dyes in effluents is a serious concern to be addressed. The chemical reduction is one of the potential way to resolve this problem. In this study, linear and crosslinked polyurethanes i.e. LPUR & CLPUR were synthesized from toluene diisocyanate (TDI), polyethylene glycol (PEG;1000g/mole) and tetraethylenepentamine (TEPA). The structure and morphology of synthesized materials were examined by FTIR, SEM and BET. The CLPUR was found stable in aqueous system with 0.80g/cm3 density and 16.4998m2g-1 surface area. These materials were applied for the reduction of methylene blue in presence of NaBH4. Both, polymers catalyzed the process and showed 100% reduction in 16 and 28mins., respectively, while, the reduction rate was significantly low in absence of these materials, even after 120mins. Furthermore, negligible adsorption was observed with only 7% removal of dye. The best reduction rates were observed at low concentration of dye, increasing concentration of NaBH4 and with more dosage of polymeric catalyst. The kinetic study of process followed zero order kinetics. It was hence concluded that both synthesized polymers played a catalytic role in reduction process. However, stability in aqueous system and better efficiency in reduction process endorsed CLPUR as an optimal choice for further studies.

A Novel Synthesis of Solid-Solid (SSMePCM) by In Situ Polymerization

In this research solid-solid microencapsulated phase change material (SSMePCM) with high thermal energy storage density (177.6 Jg/1) was synthesized successfully by in situ polymerization using biodegradable natural polymer chitosan as shell and polyethylene glycol (PEG-1000) as core. The morphology, chemical structure and thermal properties were characterized by optical microscopy (OM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The results show that the obtained SSMePCM dispersed individually with a spherical shape. Author (s) recommends the all set thermal and chemically steady microcapsule for thermal energy storage purposes as novel synthesized SSMePCM with latent heat storage capacities.