Papers by Author: Seog Jin Seo

Abstract: Human demineralized bone matrix (DBM) containing bone morphogenetic proteins (BMPs) is naturally biocompatible and can be remodeled by patients’ own bone. The major shortcoming of many of the currently used DBM gel formulations is that they have a tendency to flow, particularly if there is continuous bleeding at the application site. In this study, the physicochemical properties of human DBM were examined to improve the efficiency of DBM formulations. DBM remarkably showed higher water absorption than nondemineralized bone powder after 150 min. Hydroxyl groups in DBM appeared in fourier transform infrared analysis, although hydroxyl band in nondemineralized bone powder was not observed. The results suggested that hydrogels such as CMC, hyaluronic acid, or poloxamer as carriers can be applied for injectable DBM products, such as gel or putty types.

Abstract: The most commonly used sterilization method of human skin allografts is ethylene oxide (EO). EO gas, however, can change the biomechanical properties of the grafts and produce toxic residues which are harmful to the recipient. The heating method cannot be applied for sterilization of soft tissues because of damage due to heat. The purpose of this study was to determine whether it is possible to apply gamma-irradiation for sterilization of soft tissues as well as for hard tissues.

Abstract: In theory, Ultraviolet (UV)-generated free radicals can expedite Acellular dermal matrix (ADM) crosslinking with glucose via the formation of reactive, linear glucose molecules. The aim of this study is to maintain strength and stability of UV-irradiated ADM without the introduction of cytotoxic chemical crosslinkers. The strength and stability changes of ADM by UV-irradiated with glucose (GLUC) were investigated under various conditions. ADM strength and stability were determined by tensile testing, differential scanning calorimetry (DSC), and swelling ratio. After exposure to UV-irradiation, ADM containing glucose revealed different mechanical properties compare to ADM without glucose, greater resistance to enzymatic degradation, and higher heatdenatured breaking loads. DSC explained that glucose-incorporated ADM sterilized by UVirradiation decreased peak width (Tpeak-Ts) compared to one another. On the other hand, Area (J/g) and Ts increased glucose-incorporated ADM. The exposure of ADM to UV caused significant increase in hydration, but a significant decrease in the swelling ratio compared with the nonirradiated ADM. These data strongly suggests that free radical-dependent, glucose-derived crosslinks provide enhanced strength and enzyme resistance in glucose-incorporated, UV-exposed ADM.

Abstract: The ideal dermal matrix should be able to provide the right physical and biological environment to ensure homogenous cell and extracellular matrix (ECM) distribution, as well as the biocompatible interactions with tissue. Chitosan (CS)/poloxamer semi-interpenetrating polymer networks (SIPNs) was prepared by crosslinking of poloxamer macromer in the presence of CS in order to improve its mechanical property required in skin tissue engineering application. Furthermore, we also prepared CS/poloxamer SIPNs with ShebaTM, human acellular dermis, to overcome a low biocompatibility of the CS/poloxamer SIPNs. The CS/poloxamer SIPNs/ShebaTM showed remarkably highly cell attachment and viability in the two-dimensional (2D) culture and similar cell morphology on the CS/poloxamer SIPNs/ShebaTM compared with on tissue culturing polystylene (TCPS) as a positive control. These results suggest that CS/poloxamer SIPNs containing ShebaTM have good possibility for artificial skin system application.

Abstract: In this study, we developed an injectable carrier for demineralized bone matrix (DBM) which consists of chitosan and glycerol phosphate (GP). The phase transition behaviors of chitosan and GP solution characterized as a function of temperature. The chitosan and GP solutions were shown to form a sol at room temperature, and the chitosan solution with 10-20 wt% concentrations were found to undergo sol-to-gel phase transitions as the temperature was increased. In situ gel forming implant in vivo was successfully fabricated by simple subcutaneous injection of chitosan and GP solutions with demineralized bone matrix (DBM). von Kossa images of the gel implant formed from solution with DBM revealed the presence of mineral deposits.