Dolly Singh

Synthesis of composite gelatin-hyaluronic acid-alginate porous scaffold and evaluation for in vitro stem cell growth and in vivo tissue integration

Engineering three-dimensional (3-D) porous scaffolds with precise bio-functional properties is one of the most important issues in tissue engineering. In the present study, a three-dimensional gelatin-hyaluronic acid-alginate (GHA) polymeric composite was synthesized by freeze-drying, which was followed by ionic crosslinking using CaCl2, and evaluated for its suitability in bone tissue engineering applications. The obtained matrix showed high porosity (85%), an interconnected pore morphology and a rapid swelling behavior. The rheological analysis of GHA showed a viscoelastic characteristic, which suggested a high load bearing capacity without fractural deformation. The influence of the GHA matrix on cell growth and on modulating the differentiation ability of mesenchymal stem cells was evaluated by different biochemical and immunostaining assays. The monitoring of cells over a period of four weeks showed increased cellular proliferation and osteogenic differentiation without external growth factors, compared with control (supplemented with osteogenic differentiation medium). The in vivo matrix implantation showed higher matrix-tissue integration and cell infiltration as the duration of the implant increased. These results suggest that a porous GHA matrix with suitable mechanical integrity and tissue compatibility is a promising substrate for the osteogenic differentiation of stem cells for bone tissue engineering applications.

3D Printing of Scaffold for Cells Delivery: Advances in Skin Tissue Engineering

Injury or damage to tissue and organs is a major health problem, resulting in about half of the world’s annual healthcare expenditure every year. Advances in the fields of stem cells (SCs) and biomaterials processing have provided a tremendous leap for researchers to manipulate the dynamics between these two, and obtain a skin substitute that can completely heal the wounded areas. Although wound healing needs a coordinated interplay between cells, extracellular proteins and growth factors, the most important players in this process are the endogenous SCs, which activate the repair cascade by recruiting cells from different sites. Extra cellular matrix (ECM) proteins are activated by these SCs, which in turn aid in cellular migrations and finally secretion of growth factors that can seal and heal the wounds. The interaction between ECM proteins and SCs helps the skin to sustain the rigors of everyday activity, and in an attempt to attain this level of functionality in artificial three-dimensional (3D) constructs, tissue engineered biomaterials are fabricated using more advanced techniques such as bioprinting and laser assisted printing of the organs. This review provides a concise summary of the most recent advances that have been made in the area of polymer bio-fabrication using 3D bio printing used for encapsulating stem cells for skin regeneration. The focus of this review is to describe, in detail, the role of 3D architecture and arrangement of cells within this system that can heal wounds and aid in skin regeneration.

Effect of extracts of terminalia chebula on proliferation of keratinocytes and fibroblasts cells: An alternative approach for wound healing

Terminalia chebula is one of the traditional medicines used in the treatment of many diseases. In the present work, different concentrations of various organic and aqueous extracts (solvent-free) of T. chebula were tested on fibroblast (L929) and keratinocytes cells to evaluate its biocompatible concentration by using MTT and live-dead viability/cytotoxic assay. These extracts were found to be effective in decreasing the ammonia accumulation in the media, thereby reducing its toxic effect on cells. DPPH assay further confirmed the free-radical scavenging ability of the extracts which increased with the increase in concentration of each extract. Cell proliferation/apoptosis, cytoskeletal structure, and ECM production were further evaluated by live-dead assay and phalloidin/cytokeratin staining, respectively. The cytoskeletal structure and ECM secretion of the cells treated with extracts showed higher cellular activity in comparison to control. In conclusion, we have demonstrated the effect of these extracts of T. chebula on both types of skin cells and optimized concentration in which it could be used as a bioactive component for wound healing applications by increasing cell proliferation and decreasing free-radical production without affecting the normal cellular matrix. It can also find applications in other therapeutics applications where ammonia toxicity is a limiting factor.

Novel alginate-gelatin hybrid nanoparticle for drug delivery and tissue engineering applications

Novel alginate-gelatin hybrid nanoparticles were fabricated using single oil in water (O/W) emulsification techniques. Physicochemical property of the particle was characterized using scanning electron microscopy and Fouriers transmission infrared spectroscopy. Particle size was determined using zeta potential metastasize analyzer and was found to be in range of 400-600 nm. AGNPs were used for culturing human keratinocytes for two weeks to check biocompatibility of synthesized AGNPs. 3-(4,5- Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed increased metabolic activity of cells cultured on AGNPs in comparison to two-dimensional (2D) system (control). Cellular attachment on nanoparticle was further confirmed using SEM and 4′,6-diamidino-2-phenylindole staining. The drug release profile shows possible electrostatic bond between alginate and gelatin resulting in controlled release of drug from AGNPs. For the first time alginate-gelatin hybrid nanosystem has been fabricated and all results showed it can be used as potential system for delivery of drug and therapeutical agents to cells and can also be used for regenerative medicine applications.

Enhanced proliferation and growth of human lung epithelial cells on gelatin microparticle loaded with ephedra extracts

The objective of this work was to evaluate the effect of extracts of Ephedra gerardiana loaded onto gelatin particles on human lung epithelial cells. Particles were synthesized using oil-water emulsification technique and were further stabilized by glutaraldehyde. Particle size was evaluated using SEM and zeta potential analyzer and was found to be in the range of 600 nm-1.32 µm. Drug release profile showed controlled and constant release of extract over the period of 5 days. In vitro biocompatibility of gelatin particles loaded with solvent-free extract of Ephedra gerardiana was tested with human lung epithelial cells. Gelatin particle acted not only as scaffold for cellular adhesion but also as carrier matrix for controlled release of extracts. The cell viability was significantly high when cultured in the presence of Ephedra extract in comparison to cells without Ephedra and 2D systemas seen in MTT, SEM, and live/dead staining assay. It is concluded that gelatin microparticle functions both as drug delivery systemand scaffold; however, the main finding was the effect of Ephedra extract on human lung cells resulting in enhanced proliferation and consequent promotion of ECM production indicating that extract could be a bioactive component that can be utilized in tissue engineering and regenerative medicine.

Surfactant Role in Modifying Architecture of Functional Polymeric Gelatin Scaffolds

In this study, the authors fabricated gelatin matrices through novel foaming-freezing technique. They investigated the effect of surfactant on scaffold surface area, structure, and mechanical strength. The results confirm the use of surfactant at optimal concentration provides macroporous interconnected network to the scaffold. The sponge fabricated showed increase surface area and % elongation with use of surfactant. In vitro studies confirm higher cell attachment and proliferation with increased metabolic rate further confirmed by live/dead staining. Overall, these results show that using the surfactant can alter the architecture, surface property, and biological response of the matrix.

Interpenetrating Alginate on Gelatin- Poly (2-hydroxyethyl Methacrylate) as a Functional Polymeric Matrix for Cartilage Tissue Engineering

Abstract In this work, we report the fabrication of an interpenetrating alginate network on a gelatin and (2-hydroxyethyl methacrylate) (GAH). The anisotropic architecture of scaffold promotes the proliferation of chondrocytes. The anisotropy provided by the alginate influences the cellular response because high collagen and glycosaminoglycan (GAG) contents were found in the cells cultured on the GAH scaffold compared to the scaffold (GH) without alginate. The in vivo experiments demonstrate that the scaffold and the disposition of matrix components, particularly collagen, could promote neovascularization with the ability to recruit cells from the surrounding tissue. GRAPHICAL ABSTRACT