Decellularized bovine pericardium (DBP)-based biomeshes are the gold standard in reconstructive surgery. In order to prolong their stability after the transplantation, various chemical cross-linking strategies are employed. However, structural and functional properties of the biomeshes differ in dependence on the cross-linker used. Here, we performed a bottom-up study of structural and functional alterations of DBP-based biomeshes following cross-linking with hexamethylene diisocyanate (HMDC), ethylene glycol diglycidyl ether (EGDE), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and genipin. The in vitro cytotoxicity tests supported their clinical applicability. Their structural differences (eg roughness, fibre thickness, pore morphology) were evaluated using the two-photon confocal laser scanning, atomic force, scanning electron and polarized light microscopies. HMDC and EDC samples appeared to be the roughest. Complex mechanical trials indicated the tendency to reduced Young's Modulus and mechanical anisotropy values of DBP upon cross-linking. The lowest mechanical anisotropy was found in EDC and genipin sample groups.In vitro collagenase susceptibility was the highest for EDC samples and the lowest for EGDE samples. The comparative analysis of the results allowed us to recognize the strengths and weaknesses of each cross-linker in relation to a particular clinical application. K E Y W O R D Sbiomechanics, bovine pericardium, cross-linking, decellularization, reconstructive surgery

No abstract

No abstract

Bioprosthetic materials based on mammalian pericardium tissue are the gold standard in reconstructive surgery. Their application range covers repair of rectovaginal septum defects, abdominoplastics, urethroplasty, duraplastics, maxillofacial, ophthalmic, thoracic and cardiovascular reconstruction, etc. However, a number of factors contribute to the success of their integration into the host tissue including structural organization, mechanical strength, biocompatibility, immunogenicity, surface chemistry, and biodegradability. In order to improve the material's properties, various strategies are developed, such as decellularization, crosslinking, and detoxification. In this review, the existing issues and long‐term achievements in the development of bioprosthetic materials based on the mammalian pericardium tissue, aimed at a wide‐spectrum application in reconstructive surgery are analyzed. The basic technical approaches to preparation of biocompatible forms providing continuous functioning, optimization of biomechanical and functional properties, and clinical applicability are described.

Maintaining the epithelial status of cells in vitro and fabrication of a multilayered epithelial lining is one of the key problems in the therapy using cell technologies. When cultured in a monolayer, epithelial cells change their phenotype from epithelial to epithelial-mesenchymal or mesenchymal that makes it difficult to obtain a sufficient number of cells in a 2D culture and to use them in tissue engineering. Here, using buccal epithelial cells from the oral mucosa, we developed a novel approach to recover and maintain the stable cell phenotype and form a multilayered epithelial lining in vitro via the 2D/3D cell self-assembling. Transitioning the cells from the monolayer to non-adhesive 3D culture conditions led to formation of self-assembling spheroids, with restoration of their epithelial characteristics after epithelial-mesenchymal transition. In 7 days, the cells within spheroids restored the apical-basal polarity, and the formation of both tight (ZO1) and adherent (E-cadherin) intercellular junctions was shown. Thus, culturing buccal epithelial cells in a 3D system allowed us to recover and durably maintain the morphological and functional characteristics of epithelial cells. The multilayered epithelial lining formation was achieved after placing spheroids for 7 days onto a hybrid matrix, which consisted of collagen layers and reinforcing poly (lactide-co-glycolide) fibers and was proven promising for replacement of the urothelium. Thus, we offer an effective technique of forming multilayered epithelial linings on carrier-matrices using cell spheroids that was not previously described elsewhere and can find a wide range of applications in tissue engineering, replacement surgery, and regenerative medicine.

For efficient manufacturing of fibrous collagen-based materials by electrospinning, the search on optimal rheological parameters is of the great importance. Rheological characteristics and denaturation of collagen in aqueous dispersions were studied as a function of shear rate and acetic acid concentration in the range of 3-9% w/w at temperature from 20 to 40°C. It was shown that an increase in temperature, acetic acid concentration of the collagen dispersion leads to a significant decrease in its viscosity. It was found that helical conformation of the collagen macromolecules is preserved up to 31°C. An increase in acetic acid concentration leads to a reduction of denaturation temperature. The complex viscosity of collagen dispersions exhibits a sharp drop, followed by a rapid growth of damping factor in the temperature range from 22 to 35°C. Both storage (G') and loss (G″) moduli increase with frequency and collagen concentration. It was revealed that optimal parameters for electrospinning of highly concentrated collagen dispersions can be achieved by adjusting of the concentration of acetic acid, temperature, and stirring speed. As a result, collagen nonwoven materials with diameter from 100 to 700 nm were obtained. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part A, 2018.

The results of chemical modification of collagen from cow skin are considered. The modified product is water-soluble, stable on storage, and possesses a triple-helix structure that is characteristic of collagen. 93 0091-150X/06/4002-0093

Clinical and morphological comparison of wound healing after transplantation of living cultured allofibroblast on days 1-2 after the injury, collagen-1-based dressing with PDGF-BB, and traditional dressing with levomecol ointment showed that bioactive dressing accelerated wound epithelialization (5-7 days vs. 20-22 days with gauze dressing); the incidence of suppurative complications decreased, no crust formed, and epithelialization was not associated with the formation of a hypertrophic cicatrix. Biological dressing based on living cultured allofibroblasts and collagen-1 with PDGF-BB exhibited equal stimulatory effects on burn wound healing.