STABILITY OF ANTHOCYANIN IN MULBERRY FRUITS EXTRACT ADSORBED ON CALCIUM ALGINATE BEADS

Abstract Anthocyanins from water extracts of the mulberry fruits (Morus alba L./Jul cultivars) were adsorbed on calcium alginate beads. The beads were produced by external gelation using different concentrations of alginate solution. The calcium alginate beads were studied on capability of water, mulberry extract adsorption and anthocyanin stability at high temperature. The adsorption ability of the bead was found to be depended on the pH of the aqueous media. Mulberry extracts (pH4.3) had the highest adsorption at 1684.30±154.80 %(wt/wt). Beads (1.5%Alginate, ALG) average size were at 415.63±13.09 µm. Water (pH6.8) adsorption of the same type of beads was at 242.68±2.59 %(wt/wt) (325.00±17.09 µm). Anthocyanin encapsulation efficiency was at 17.08±0.25 mg/g Dry weight. Stability of adsorbed anthocyanin on calcium alginate bead was studied. After heat exposure at 40 o C and 100 o C for 10 hrs, anthocyanin was at 92%wt and 24%wt, respectively. Calcium alginate beads enhanced anthocyanin stability in the beads at these conditions by 10-40%. These results provided the useful data for process and storage condition of mulberry products

Osteogenic differentiation of encapsulated cells in dexamethasone-loaded phospholipid-induced silk fibroin hydrogels

The tissue engineering triad comprises the combination of cells, scaffolds and biological factors. Therefore, we prepared cell- and drug-loaded hydrogels using in situ silk fibroin (SF) hydrogels induced by dimyristoyl glycerophosphoglycerol (DMPG). DMPG is reported to induce rapid hydrogel formation by SF, facilitating cell encapsulation in the hydrogel matrix while maintaining high cell viability and proliferative capacity. In addition, DMPG can be used for liposome formulations in entrapping drug molecules. Dexamethasone (Dex) was loaded into the DMPG-induced SF hydrogels together with human osteoblast-like SaOS-2 cells, then the osteogenic differentiation of the entrapped cells was evaluated in vitro and compared to cells cultured under standard conditions. Calcium production by cells cultured in DMPG/Dex-SF hydrogels with Dex-depleted osteogenic medium was equivalent to that of cells cultured in conventional osteogenic medium containing Dex. The extended-release of the entrapped Dex by the hydrogels was able to provide a sufficient drug amount for osteogenic induction. The controlled release of Dex was also advantageous for cell viability even though its dose in the hydrogels was far higher than that in osteogenic medium. The results confirmed the possibility of using DMPGinduced SF hydrogels to enable dual cell and drug encapsulation to fulfil the practical applications of tissue-engineered constructs.This research was partially supported by the Asahi Glass Foundation (grant number: RES_65_530_33_026). CL would like to express gratitude for the Second Century Fund (C2F), Chulalongkorn University, for the support of a post-doctoral fellowship

The Effect of Sericin from Various Extraction Methods on Cell Viability and Collagen Production

Silk sericin (SS) can accelerate cell proliferation and attachment; however, SS can be extracted by various methods, which result in SS exhibiting different physical and biological properties. We found that SS produced from various extraction methods has different molecular weights, zeta potential, particle size and amino acid content. The MTT assay indicated that SS from all extraction methods had no toxicity to mouse fibroblast cells at concentrations up to 40 μg/mL after 24 h incubation, but SS obtained from some extraction methods can be toxic at higher concentrations. Heat-degraded SS was the least toxic to cells and activated the highest collagen production, while urea-extracted SS showed the lowest cell viability and collagen production. SS from urea extraction was severely harmful to cells at concentrations higher than 100 μg/mL. SS from all extraction methods could still promote collagen production in a concentration-dependent manner, even at high concentrations that are toxic to cells

The Production and Application of Hydrogels for Wound Management: A Review

Wound treatment has increased in importance in the wound care sector due to the pervasiveness of chronic wounds in the high-risk population including, but not limited to, geriatric population, immunocompromised and obese patients. Furthermore, the number of people diagnosed with diabetes is rapidly growing. According to the World Health Organization (WHO), the global diabetic occurrence has increased from 4.7 in 1980 to 8.5 in 2014. As diabetes becomes a common medical condition, it has also become one of the major causes of chronic wounds which require specialised care to address patients’ unique needs. Wound dressings play a vital role in the wound healing process as they protect the wound site from the external environment. They are also capable of interacting with the wound bed in order to facilitate and accelerate the healing process. Advanced dressings such as hydrogels are designed to maintain a moist environment at the site of application and due to high water content are ideal candidates for wound management. Hydrogels can be used for both exudating or dry necrotic wounds. Additionally, hydrogels also demonstrate other unique features such as softness, malleability and biocompatibility. Nowadays, advanced wound care products make up around 7.1 billion of the global market and their production is growing at an annual rate of 8.3 with the market projected to be worth 12.5 billion by 2022. The presented review focuses on novel hydrogel wound dressings, their main characteristics and their wound management applications. It also describes recent methodologies used for their production and the future potential developments

Comparative Study of Silk Fibroin-Based Hydrogels and Their Potential as Material for 3-Dimensional (3D) Printing

Three-dimensional (3D) printing is regarded as a critical technology in material engineering for biomedical applications. From a previous report, silk fibroin (SF) has been used as a biomaterial for tissue engineering due to its biocompatibility, biodegradability, non-toxicity and robust mechanical properties which provide a potential as material for 3D-printing. In this study, SF-based hydrogels with different formulations and SF concentrations (1–3%wt) were prepared by natural gelation (SF/self-gelled), sodium tetradecyl sulfate-induced (SF/STS) and dimyristoyl glycerophosphorylglycerol-induced (SF/DMPG). From the results, 2%wt SF-based (2SF) hydrogels showed suitable properties for extrusion, such as storage modulus, shear-thinning behavior and degree of structure recovery. The 4-layer box structure of all 2SF-based hydrogel formulations could be printed without structural collapse. In addition, the mechanical stability of printed structures after three-step post-treatment was investigated. The printed structure of 2SF/STS and 2SF/DMPG hydrogels exhibited high stability with high degree of structure recovery as 70.4% and 53.7%, respectively, compared to 2SF/self-gelled construct as 38.9%. The 2SF/STS and 2SF/DMPG hydrogels showed a great potential to use as material for 3D-printing due to its rheological properties, printability and structure stability

Hydrogelation of Regenerated Silk Fibroin via Gamma Irradiation

Gamma irradiation, which is one of the more conventional sterilization methods, was used to induce the hydrogelation of silk fibroin in this study. The physical and chemical characteristics of the irradiation-induced silk fibroin hydrogels were investigated. Silk fibroin solution with a concentration greater than 1 wt% formed hydrogel when irradiated by gamma rays at a dose of 25 or 50 kGy. The hydrogel induced by 50 kGy of radiation was more thermally stable at 80 °C than those induced by 25 kGy of radiation. When compared to the spontaneously formed hydrogels, the irradiated hydrogels contained a greater fraction of random coils and a lower fraction of β-sheets. This finding implies that gelation via gamma irradiation occurs via other processes, in addition to crystalline β–sheet formation, which is a well-established mechanism. Our observation suggests that crosslinking and chain scission via gamma irradiation could occur in parallel with the β–sheet formation. The irradiation-induced hydrogels were obtained when the solution concentration was adequate to support the radiation crosslinking of the silk fibroin chains. This work has, therefore, demonstrated that gamma irradiation can be employed as an alternative method to produce chemical-free, random coil-rich, and sterilized silk fibroin hydrogels for biomedical applications

Impacts of Blended <i>Bombyx mori</i> Silk Fibroin and Recombinant Spider Silk Fibroin Hydrogels on Cell Growth

Binary-blended hydrogels fabricated from Bombyx mori silk fibroin (SF) and recombinant spider silk protein eADF4(C16) were developed and investigated concerning gelation and cellular interactions in vitro. With an increasing concentration of eADF4(C16), the gelation time of SF was shortened from typically one week to less than 48 h depending on the blending ratio. The biological tests with primary cells and two cell lines revealed that the cells cannot adhere and preferably formed cell aggregates on eADF4(C16) hydrogels, due to the polyanionic properties of eADF4(C16). Mixing SF in the blends ameliorated the cellular activities, as the proliferation of L929 fibroblasts and SaOS-2 osteoblast-like cells increased with an increase of SF content. The blended SF:eADF4(C16) hydrogels attained the advantages as well as overcame the limitations of each individual material, underlining the utilization of the hydrogels in several biomedical applications