The goal of tissue engineering is to repair or regenerate damaged tissue using a combination of cellular biology and materials engineering techniques. One of the challenging problems in tissue engineering is the development of a reproducible three-dimensional (3D) scaffold to support cell migration and infiltration. Although natural polymers, such as dissolved collagen or alginate, are considered ideal for this purpose, their hydrophilic properties have hindered the fabrication of designed 3D scaffold structures. To overcome this problem, we developed a novel system for the cryogenic plotting of 3D scaffolds. Using this technique, we created various 3D collagen scaffolds with designed pore structures that exhibited desired properties. The diameter of the individual collagen strands, which varied from 250 mm to 500 mm, was reproducibly dependent on processing parameters, and the final collagen scaffold showed little shrinkage (less than 12%) relative to the initial design. To evaluate the fabricated scaffold, we adapted the scaffold to regenerate skin tissue. Immunohistochemical analysis demonstrated that co-cultured keratinocytes and fibroblasts completely migrated throughout the 3D collagen scaffold and keratinocytes were well differentiated on the surface of scaffold like a human skin.
One of the challenges in tissue engineering is the development of a reproducible three-dimensional (3D) scaffold to support cell migration and infiltration. As a dermal substitute, 3D collagen scaffolds with precisely controlled pore structures were fabricated using an innovative cryogenic dispenser system. The scaffolds were composed of perpendicular, highly porous collagen strands in successive layers. The fabricated scaffolds were evaluated in an in vitro keratinocyte/fibroblast coculture test. Fibroblasts were well dispersed within the scaffold, and keratinocytes had completely migrated through the well-designed pore structure and differentiated on top of the scaffold surface. The differentiated keratinocytes generated a stratum corneum in the 3D dispensed scaffolds, similar to that in normal skin tissue.
Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.
The beneficial effects of ginger in the management of gastrointestinal disturbances have been reported. In this study, the anti-inflammatory potential of ginger extract was assessed in a cellular model of gut inflammation. In addition, the effects of ginger extract and its major active compounds on intestinal barrier function were evaluated. The response of Caco-2 cells following exposure to a mixture of inflammatory mediators [interleukin [IL]-1β, 25 ng/mL; lipopolysaccharides [LPS], 10 ng/mL; tumor necrosis factor [TNF]-α, 50 ng/mL; and interferon [INF]-γ, 50 ng/mL] were assessed by measuring the levels of secreted IL-6 and IL-8. In addition, the mRNA levels of cyclooxygenase-2 and inducible nitric oxide synthase were measured. Moreover, the degree of nuclear factor (NF)-κB inhibition was examined, and the intestinal barrier function was determined by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran transfer. It was observed that ginger extract and its constituents improved inflammatory responses by decreasing the levels of nitrite, PGE2, IL-6, and IL-8 via NF-κB inhibition. The ginger extract also increased the TEER and decreased the transfer of FITC-dextran from the apical side of the epithelium to the basolateral side. Taken together, these results show that ginger extract may be developed as a functional food for the maintenance of gastrointestinal health.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.