Roli Purwar

Flexible Silk Fibroin Films for Wound Dressing

In the present study, an effort has been made to create dextrose incorporated (5-15 % w/w) flexible silk fibroin films for wound dressing applications. The flexibility of silk fibroin films increases with increase in dextrose content. The elongation at break properties of dextrose modified silk fibroin (DMSF) films increases from 3.2 % to 40 % with increase in dextrose content. The glass transition temperature (Tg) of the films decreases from 176 °C to 155 °C with increase in dextrose content. This shows that dextrose is acting as plasticizer for silk fibroin films. The structural and morphological properties of dextrose modified silk films (DMSF) are characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) scanning electron microscopy (SEM) and atomic force microscopy (AFM). FTIR and XRD studies show that the dextrose content does not affect the crystalline structure of silk fibroin films. The surface roughness of the films also increases with increases in dextrose content in DMSF films. The addition of dextrose enhances the swelling and hydrophilicity of silk fibroin films. The adherence, proliferation and viability of L929 fibroblast cells cultured on DMSF films indicate that it has ability to support cell growth and proliferation as compared to SF film. The 15 % DMSF film showed significantly higher mass loss than SF film after 50 days of incubation in Protease XIV. Further, the data presented here constitute strong evidence that dextrose modified film has the great potential to be utilized as dermal wound dressing material.

Flexible sericin/polyvinyl alcohol/clay blend films

This paper describes the preparation and characterization of flexible crosslinked Sericin/Polyvinyl alcohol (PVA)/ Clay blend films. Sericin/PVA (1:1 w/w) blend films are prepared by using glutaraldehyde as crosslinking agent, glycerol as plasticizer, Cloisite 30B and Sodium montmorillonite as nanoclays by solution casting method. The concentrations of glutaraldehyde, glycerol and nanoclays are optimized on the basis of mechanical properties of the blend films. It is observed that the tensile strength and elastic modulus of the crosslinked flexible Sericin/PVA film is enhanced on addition of clay. The blend films are characterized for structural, morphological and thermal properties. Fourier transform infrared spectra showed that gulteraldehyde chemically crossliked with PVA and Sericin. Scanning electron micrographs and tanδ thermograms revealed that the addition of gluteraldehyde is reduced the phase separation between Sericin and PVA in the blend films. The XRD spectra showed that clay is intercalated in Sericin/PVA matrix. Clays are completely dispersed in Sericin/PVA blend solution as observed in transmission electron microscopy (TEM).

Fabrication of robust Antheraea assama fibroin nanofibrous mat using ionic liquid for skin tissue engineering

Electrospinning is an emerging technique used for fabrication of nanofibrous mats for skin tissue engineering applications. The aim of this study centered on fabrication of muga fibroin electrospun mats by using ionic liquid and its characterizations. The muga fibroin extracted from cocoon of Antheraea assama is dissolved in 1-butyl, 3-methyl imidazolium acetate (BMIMAc), a green solvent, to prepare a dope solution for electrospinning. The molecular weight, rheology and structural properties of dope solution are characterized. The process parameters of electrospinning machine such as voltage and concentration of dope solution are varied to obtain nanofibrous mats. The nanofibrous mat having average fiber diameter of 160nm are obtained from 10% w/v concentration of muga fibroin in BMIMAc with an applied voltage of 20KV. The mechanical, structural, physical and thermal properties of muga nanofibrous mat (MNF) are analyzed and compare with muga cast film. The cytocompatibility test is performed using L929 fibroblast cells. It is observed that muga nanofibrous mat support higher growth of fibroblast cells (p<0.05) as compared to muga cast film (MCF). Muga nanofibrous mat and cast film are loaded with gentamycin sulphate. The release rate and antimicrobial efficiency of gentamycin sulphate loaded muga nanofibrous mat are found to be significantly higher (p<0.05) as compared to muga cast film. All these results indicate that muga nanofibrous mat would be a promising material for skin tissue engineering.

Composite Wound Dressing for Drug Release

Present study is focused on the preparation of two layers composite wound dressing for drug release. The outer layer is made of hydrogel which contains of drug and the core layer is made of fabric. The two layers structure of composite dressing is formed by grafting of polyacrylamide-co-acrylic acid hydrogel on cotton fabric using ammonium per sulphate (APS) as chemical initiator and polyethylene glycol (PEG) as crosslinker. The major factors affecting graft copolymerization of hydrogel on cotton fabric are optimized by varying concentration of monomers & initiator, reaction temperature and addition time of crosslinker. Maximum grafting of hydrogel is obtained at 5 % (w/v) APS and 15 % acrylamide/acrylic acid (1:1 w/w ratio) concentration. The FTIR spectra of composite dressing shows characteristics peak of acrylic acid and acrylamide. The composite wound dressing material is loaded with model drug bovine serum albumin (BSA) and drug release behaviour is studied at different pH. The dressing shows drug release in different pH with maximum release of drug in acidic medium.

Electrospun Sericin/PVA/Clay nanofibrous mats for antimicrobial air filtration mask

In this study, Sericin/Poly Vinyl Alcohol (PVA)/Clay (Cloisite 30B) nanofibrous mats are prepared by electrospinning technique for antimicrobial air filtration mask. The process parameters of electro-spinning machine such as acceleration voltage, nozzle flow rate and nozzle & collector distance are optimised on the basis of morphology of fibre observed through scanning electron microscopy (SEM). The optimum conditions for producing nanofibrous mat without bead are acceleration voltage 27.5 kV, nozzle collector distance 8 cm and flow rate 0.8 ml/hr using 10 % (w/v) solution of Sericin/PVA (1:1 wt/wt). The process parameters of electro-spinning machine for the processing of Sericin/PVA/Clay nanofibrous mats with varied clay concentrations ranging from 0.1-0.75 % are also optimized. The spun fibre diameter varied from 300-400 nm at different specified conditions. These nanofibrous mats are characterized for its structural, mechanical and antimicrobial properties. Respirable Suspended Particulate Matter (RSPM) test was conducted to check the particulate matter (PM 2.5) absorption capacity of nanofibrous mats. Results shows that sericin/PVA/clay nanofibrous mat would be a promising material for making protecting clothing based air filtration mask.

Dextrose modified flexible tasar and muga fibroin films for wound healing applications

This paper is focused on preparation and characterization of regenerated muga and tasar fibroin flexible films from cocoon using ionic liquid. These flexible muga and tasar fibroin films were prepared by incorporating dextrose (5 to 15% w/w) as plasticizer. The mechanical, thermal, physical, morphological and biological properties of dextrose plasticized muga and tasar fibroin films were characterized. These plasticized films showed higher elongation at break as well as water holding capacity as compared to the un-plasticized films. The surface roughness and water absorbance capacity of the dextrose plasticized films were higher than un-plasticized films, which results in improved adherence and proliferation of L929 fibroblast cells. Gentamicin loaded plasticized muga and tasar fibroin films showed slightly higher rate of release as compared to un-plasticized films. The biodegradability of dextrose plasticized films was significantly higher as compared to their respective counterpart. The regeneration of flexible muga and tasar silk fibroin films pave the way to expand potential use of non-mulberry in the field of biomedical such as wound dressing.

Fabrication of 3D Self-Assembled Nonmulberry Antheraea Mylitta (tasar) Fibroin Nonwoven Mats for Wound Dressing Applications

This research was focused on the two-step regeneration of Antheraea mylitta (tasar) fibroin in the form of electrospun 3D self-assembled nanofibrous nonwoven mats using ionic liquid and formic acid/CaCl2. The self-assembled structure of tasar nanofibrous nonwoven mats was dependent on the silk fibroin concentration and spinning voltage. The secondary conformation of tasar fibroin protein before and after electrospinning was analyzed by Fourier transformation infrared spectroscopy. The morphology of the nanofibrous mat was studied by scanning electron microscope. The self-assembled 3D tasar nonwoven nanofibrous construct was a highly porous and spongy structure with high water absorption and water vapor transmission. Highly porous 3D self-assembled tasar nonwoven nanofibrous construct favored good growth and proliferation of L929 skin fibroblast cells. Based on these properties, 3D self-assembled tasar nonwoven nanofibrous construct is a promising material for skin tissue engineering and wound dressing applications.