Cellulose film regenerated from Styela clava tunics have biodegradability, toxicity and biocompatibility in the skin of SD rats.

Cellulose is one of the most widespread biomolecules in nature and has been exploited in various applications including scaffolding, tissue engineering, and tissue formation. To evaluate the biocompatibility of cellulose film manufactured from Styela clava tunics (SCT-CF), these films were implanted in Sprague-Dawley (SD) rats for various lengths of time, after which they were subjected to mechanical and biological analyses. The cellulose powders (12-268 m) obtained from SCT was converted into films via casting methods without adding any additives. SCT-CF contained about 98 % α-cellulose and very low concentrations of ßß-cellulose. Additionally, the crystallinity index (CrI) of SCT-CF was lower (10.71 %) than that of wood pulp-cellulose films (WP-CF) (33.78 %). After implantation for 90 days, the weight loss and formation of surface corrugations were greater in SCT-CF than that of WP-CF, while the surface roughness was significantly higher in WP-CF than SCT-CF. However, there were no differences in the number of white blood cells between SCT-CF implanted rats and vehicle implanted rats. The level of metabolic enzymes representing liver and kidney toxicity in the serum of SCT-CF implanted rats was maintained at levels consistent with vehicle implanted rats. Moreover, no significant alteration of the epidermal hyperplasia, inflammatory cell infiltration, redness, and edema were observed in SD rats implanted with SCT-CF. Taken together, these results indicate that SCT-CF showed good degradability and non-toxicity without inducing an immune response in SD rats. Further, the data presented here constitute strong evidence that SCT-CF has the potential for use as a powerful biomaterial for medical applications including stitching fiber, wound dressing, scaffolding, absorbable hemostats and hemodialysis membrane.

Therapeutic effects of a liquid bandage prepared with cellulose powders from Styela clava tunics and Broussonetia kazinoki bark: Healing of surgical wounds on the skin of Sprague Dawley rats.

Cellulose in different forms has extensively been applied in biomedical treatments, including scaffolding, tissue engineering and tissue formation. To evaluate the therapeutic effects of a liquid bandage (LB) prepared with cellulose powders from Styela clava tunics (SCT) and Broussonetia kazinoki bark (BSLB) for healing cutaneous wounds, the remedial effects of a low concentration (LoBSLB) and a high concentration (HiBSLB) of BSLB on skin regeneration and toxicity in Sprague Dawley rats. Results indicated that the total area of skin involved in the surgical wound was lower in the BSLB­treated group compared with the Vehicle­treated group at days 4­12, although some variations were observed in the HiBSLB­treated group. In addition, the BSLB­treated group showed significantly enhanced width of the re­epithelialization region and epidermal thickness when compared with the Vehicle­treated group. Furthermore, significant stimulation in the expression level of collagen­1 and the signaling pathway of VEGF after topical application of BSLB was indicated. No liver or kidney toxicities were detected for either doses of BSLB. Overall, the results of the present study suggest that BSLB accelerates the process of wound healing in surgical skin wounds of Sprague Dawley rats through stimulation of re­epithelialization and connective tissue formation, without any accompanying significant toxicity.

Effects of different cellulose membranes regenerated from Styela clava tunics on wound healing.

The aim of this study was to investigate the therapeutic effects of three different cellulose membranes (CMs) manufactured from Styela clava tunics (SCTs) on the healing of cutaneous wounds. We examined the physical properties and therapeutic effects of three CMs regenerated from SCTs (referred to as SCT­ CMs), including normal CM (SCT­CM), freeze-dried SCT­CM (FSCT­CM) and sodium alginate-supplemented SCT­CM (ASCT­CM) on skin regeneration and angiogenesis using Sprague-Dawley (SD) rats. FSCT­CM exhibited an outstanding interlayered structure, a high tensile strength (1.64 MPa), low elongation (28.59%) and a low water vapor transmission rate (WVTR) compared with the other SCT-CMs, although the fluid uptake rate was maintained at a medium level. In the SD rats with surgically wounded skin, the wound area and score of wound edge were lower in the FSCT­CM-treated group than in the gauze (GZ)-treated group on days 3-6 and 12-14. In addition, a significant attenuation in the histopathological changes was observed in the FSCT­CM-treated group. Furthermore, the expression level of collagen-1 and the signaling pathway of transforming growth factor (TGF)-ß1 were significantly stimulated by the topical application of FSCT­CM. However, no signs of toxicity were detected in the livers or kidneys of the three SCT­CM-treated groups. Overall, our data indicate that the FSCT­CM may accelerate the process of wound healing in the surgically wounded skin of SD rats through the regulation of angiogenesis and connective tissue formation without inducing any specific toxicity.

Bacterial cellulose membrane produced by Acetobacter sp. A10 for burn wound dressing applications.

Bacteria cellulose membranes (BCM) are used for wound dressings, bone grafts, tissue engineering, artificial vessels, and dental implants because of their high tensile strength, crystallinity and water holding ability. In this study, the effects of BCM application for 15 days on healing of burn wounds were investigated based on evaluation of skin regeneration and angiogenesis in burn injury skin of Sprague-Dawley (SD) rats. BCM showed a randomly organized fibrils network, 12.13 MPa tensile strength, 12.53% strain, 17.63% crystallinity, 90.2% gel fraction and 112.14 g × m(2)/h highest water vapor transmission rate (WVTR) although their swelling ratio was enhanced to 350% within 24h. In SD rats with burned skin, the skin severity score was lower in the BCM treated group than the gauze (GZ) group at all time points, while the epidermis and dermis thickness and number of blood vessels was greater in the BCM treated group. Furthermore, a significant decrease in the number of infiltrated mast cells and in vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) expression was observed in the BCM treated group at day 10 and 15. Moreover, a significant high level in collagen expression was observed in the BCM treated group at day 5 compared with GZ treated group, while low level was detected in the same group at day 10 and 15. However, the level of metabolic enzymes representing liver and kidney toxicity in the serum of BCM treated rats was maintained at levels consistent with GZ treated rats. Overall, BCM may accelerate the process of wound healing in burn injury skin of SD rats through regulation of angiogenesis and connective tissue formation as well as not induce any specific toxicity against the liver and kidney.

Increased production of bacterial cellulose by Acetobacter sp. V6 in synthetic media under shaking culture conditions.

Acetobacter strains are bacteria that can synthesize cellulose when grown in a complex medium containing glucose. The effect of the components of a synthetic medium on bacterial cellulose (BC) production by a newly isolated Acetobacter sp. V6 in shaking cultures was investigated. BC production was dependent on the presence of MgSO4 x 7H2O and cosubstrates such as ethanol and lactic acid in the medium. The optimal synthetic medium contained 1.5% glucose, 0.2% (NH4)2SO4, 0.3% KH2PO4, 0.3% Na2HPO4 x 12H2O, 0.08% MgSO4 x 7H2O, 0.0005% FeSO4 x 7H2O, 0.0003% H3BO3, 0.00005% nicotinamide, and 0.6% ethanol. A maximum BC concentration of 4.16 g/l was achieved after 8 days of cultivation at 200 rpm. The production of BC by Acetobacter sp. V6 was higher in synthetic medium than complex medium (Hestrin and Schramm medium) traditionally used for Acetobacter strains.

Production and characterization of cellulose by Acetobacter sp. V6 using a cost-effective molasses-corn steep liquor medium.

In order to reduce of the manufacturing cost of bacterial cellulose (BC), BC production by Acetobacter sp. V6 was investigated in shaking culture using molasses and corn steep liquor (CSL) as the sole carbon and nitrogen sources, respectively. The highest BC production was obtained with Ca3(PO4)2-treated molasses. Maximum BC yield (2.21+/-0.04 g/l) was obtained at 5% (w/v) total sugar in molasses. In improved medium containing molasses and CSL, BC production was observed in the medium after 1 day of incubation and increased rapidly thereafter with maximum yield (3.12+/-0.03 g/l) at 8 days. This value was approximately twofold higher than the yield in the complex medium. Physical properties of BC from the complex and molasses media were studied using Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffractometer. By FT-IR, all the BC were found to be of cellulose type I, the same as typical native cellulose. The relative crystallinity of BC produced in the complex and molasses media were 83.02 and 67.27%, respectively. These results suggest that molasses and CSL can be useful low-cost substrates for BC production by Acetobacter sp. V6 without supplementation with expensive nitrogen complexes such as yeast extract and polypeptone, leading to the reduction in the production costs.

Influence of glycerol on production and structural-physical properties of cellulose from Acetobacter sp. V6 cultured in shake flasks.

Cost-effective production of bacterial cellulose (BC) by Acetobacter sp. V6 was investigated in shake culture using glycerol as carbon source and its structural and physical properties were determined. In medium containing 3% (w/v) glycerol, BC production was 4.98+/-0.03g/l after 7 days. This value was 3.8-fold higher than the yield in the glucose medium. FT-IR spectra revealed that all the BC samples were highly crystalline and were cellulose type capital I, Ukrainian. The crystallinity index value of the BC produced was 9% higher in the glycerol medium than in the glucose medium. Scanning electron micrographs showed that BC from the glycerol medium was more compact than that from the glucose medium. Water-holding capacity and viscosity of BC from the glycerol medium had 61.3% and 22.4% lower values than those from the glucose medium. These results suggest that glycerol could be a potential low-cost substrate for BC production by Acetobacter sp. V6, leading to the reduction in the production cost.

Development of an optimized, simple chemically defined medium for bacterial cellulose production by Acetobacter sp. A9 in shaking cultures.

The genus Acetobacter can synthesize cellulose when grown in an undefined medium containing glucose. By using the technique of the omission of a single medium component, an optimized and simple chemically defined medium was developed to support cellulose production by Acetobacter sp. A9 in shaking culture. It contained 4.0% (w/v) glucose, 0.2% (w/v) (NH(4))(2)SO(4), 0.25% (w/v) KH(2)PO(4), 0.3% (w/v) Na(2)HPO(4).12H(2)O, 0.05% (w/v) MgSO(4).7H(2)O, 0.0002% (w/v) FeSO(4).7H(2)O, 0.00025% (w/v) H(3)BO(3), 0.00006% (w/v) nicotinamide, 0.00025% (w/v) inositol and 1.4% (v/v) ethanol. A maximum cellulose concentration of around 8 g/l was achieved after 9 days of cultivation at 200 rev./min. The production of cellulose by Acetobacter sp. A9 was greater in simplified synthetic medium than in complex medium (Hestrin and Schramm medium) conventionally used for Acetobacter strains.