Soon Mo Choi

Porous Three-Dimensional PVA/Gelatin Sponge for Skin Tissue Engineering

A series of PVA/gelatin scaffolds in different concentrations were prepared and blended to evaluate the polymer concentration effects on the architecture of the scaffold. SEM images revealed that with increasing gelatin concentration the average pore diameters varied from 60 to 190 nm. Bio-compatibility assay showed cells attached and elongated actively on the scaffolds and cyto-toxicity results of all samples were found to be in grade 1 or 0, indicating the bio-safety of PVA/gelatin as biomaterial. Results indicate the polymer concentration effects on the architecture of the scaffold and PVA/gelatin macroporous scaffolds have potential to be bio-matrices for tissue genesis.

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.

Advances in Waterborne Polyurethane-Based Biomaterials for Biomedical Applications

Polyurethane (PU) is one of the most popular synthetic elastomers and widely employed in biomedical fields owing to the excellent biocompatibility and hemocompatibility known today. In addition, PU is simply prepared and its mechanical properties such as durability, elasticity, elastomer-like character, fatigue resistance, compliance or tolerance in the body during the healing, can be mediated by modifying the chemical structure. Furthermore, modification of bulk and surface by incorporating biomolecules such as anticoagulant s or biorecognizable groups, or hydrophilic/hydrophobic balance is possible through altering chemical groups for PU structure. Such modifications have been designed to improve the acceptance of implant. For these reason, conventional solventborne (solvent-based) PUs have established the standard for high performance systems, and extensively used in medical devices such as dressings, tubing, antibacterial membrane , catheters to total artificial heart and blood contacting materials, etc. However, waterborne polyurethane (WPU) has been developed to improve the process of dissolving PU materials using toxic organic solvents, in which water is used as a dispersing solvent. The prepared WPU materials have many advantages, briefly (1) zero or very low levels of organic solvents, namely environmental-friendly (2) non-toxic, due to absence of isocyanate residues, and (3) good applicability caused by extensive structure/property diversity as well as an environment-friendly fabrication method resulting in increasing applicability. Therefore, WPUs are being in the spotlight as biomaterials used for biomedical applications . The purpose of this review is to introduce an environmental- friendly synthesis of WPU and consider the manufacturing process and application of WPU and/or WPU based nanocomposites as the viewpoint of biomaterials.

Advances in Protein-Based Materials: From Origin to Novel Biomaterials

Biomaterials play a very important role in biomedicine and tissue engineering where they directly affect the cellular activities and their microenvironment . Myriad of techniques have been employed to fabricate a vast number natural, artificial and recombinant polymer s in order to harness these biomaterials in tissue regene ration , drug delivery and various other applications. Despite of tremendous efforts made in this field during last few decades, advanced and new generation biomaterials are still lacking. Protein based biomaterials have emerged as an attractive alternatives due to their intrinsic properties like cell to cell interaction , structural support and cellular communications. Several protein based biomaterials like, collagen , keratin , elastin , silk protein and more recently recombinant protein s are being utilized in a number of biomedical and biotechnological processes. These protein-based biomaterials have enormous capabilities, which can completely revolutionize the biomaterial world. In this review, we address an up-to date review on the novel, protein-based biomaterials used for biomedical field including tissue engineering, medical science, regenerative medicine as well as drug delivery. Further, we have also emphasized the novel fabrication techniques associated with protein-based materials and implication of these biomaterials in the domain of biomedical engineering .

Fabrication of highly electrical synthetic leather with polyurethane/poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate)

Abstract Poly(ethylene-3,4-dioxythiophene)/poly(styrene sulfonic acid)(PEDOT/PSS) water dispersions are commercially available, and various coating formulations for substrates, such as glass, plastics, and ceramics, have been suggested. Recently, it was found that the addition of a small amount of organic solvent, such as ethylene glycol (EG) and dimethylsulfoxide (DMSO), to the aqueous dispersion of PEDOT/PSS increases the conductivity significantly. This study examined how a combination of solvent addition affects the PEDOT/PSS conductivity of artificial leather (napping fabric with short fur). In addition, the sustainability of the PEDOT/PSS conductivity for the common use of artificial leather was investigated using abrasion and tension cycle tests. The electric conductivity of the leather increased in the order of EG < DMSO < EG + DMSO. The sustainability of the PEDOT/PSS conductivity in the case of EG + DMSO was superior to that of the EG or DMSO solvents. The padding process was found to be a more effective method for achieving durability against abrasion and tension cycle with a lower deposit weight than when using the coating process. The mechanical properties of the synthetic leather using the padding process also showed high performance compared to the coating process.

Design and development of functional fabrics with dust- and sound- absorbing properties

In an environmentally polluted environment, woven curtain fabrics that collect dust and pollen play an important health-protective role in interior decoration. However, devices or evaluation factors for measuring the dust adsorption ability of interior products have not been developed. To resolve this deficiency, we developed an apparatus that directly measures the dust adsorption and devised two test parameters (dust interrupting capability and fine dust adsorption capacity) for quantifying the dust adsorption. We also investigated the physical properties affecting the dust adsorption ability of fabrics with different denier weaves of air-textured yarns and draw-textured yarns, which adsorb dust in their fluffs and crimps, respectively. The air permeability and weight of the fabrics were strongly correlated with fine dust interrupting capability. The air permeability, dust adsorption, and interruption capability of the air-textured yarns largely depended on the loops formed by the overfeed rate in the weft direction. The strong sound-absorbing performance of the samples (especially at higher frequencies) was also obtained by loops, fluffs, and crimps of air-textured yarns and draw-textured yarns of fabrics. The best sound-absorbing performance was exhibited by S20, made from 760 D with many loops on the yarn surface.

Functionalizing cellulose scaffold prepared by ionic liquid with bovine serum albumin for biomedical application

The present study reports the preparation of a cellulose scaffold for tissue engineering directly from cellulose fiber using ionic liquid (IL) by the NaCl leaching method with bovine serum albumin (BSA), which is well known protein utilized for biomedical applications like degradation of polymer, cell attachment and proliferation on scaffold. The 1-n-allyl-3-methylimidazolium chloride (AmimCl) IL was used as a solvent for cellulose. The morphology of the scaffold was studied by scanning electron microscopy (SEM) and the images showed that the pore sizes of the scaffolds were about 200 µm. In addition, the water uptake (WU) and degree of degradation of the cellulose scaffold were measured. Meanwhile, the biocompatibility and bioactivity of the scaffold were determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide (MTT) assay and the Live/Dead viability test. The various results demonstrated the ability of the Mesenchymal stem cells (MSC) to attach to the surface of the scaffolds amplified as percentage of BSA increased in cellulose scaffold.