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류지현,이해신 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
In nature, a variety of water-insoluble materials are biologically synthesized by water-soluble precursors. This water-basis, environment-friendly biochemical strategy evolutionally optimized in nature can solve problems in present un-sustainable society caused by petroleum-based olefin materials. Here, we aim at the spontaneous formation of water-insoluble, biocompatible microfilms from water-soluble polymers without using any additives inspired by insect cuticle formation. Water-soluble chitosan-catechol polymeric precursor is spontaneously converted to flexible thin films by the simple dehydration process. Considering most water-soluble polymers form powders when dehydrated, the preparation of mechanically robust, water-insoluble, flexible chitosan film is the completely unexpected result. This film can be used as a conventional bag similar to polyvinyl one and is multifunctional, biocompatible material for drug delivery depots and tissue engineering applications.
Intraperitoneal adhesive patch: A novel approach for bio-adhesives
류지현 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Herein, we report a fluid-resistant adhesive intraperitoneal (IP) patch that seals intestinal neo-anastomosis sites, preventing anastomotic leakage after colorectal surgery. Dressing with IP patches reliably seals intestinal incision sites, resulting in significant reduction of anastomotic leakage after colorectal surgery. Additionally, IP patches can act as unprecedented local drug reservoirs due to the tissue adhesive property. Drug-loaded IP patches successfully treated multiple-site occurrence of small peritoneal cancerous colonies. Thus, the multi-functionality of IP patches can be usefully exploited as an adhesive biomaterial that works effectively in difficult-to-treat diseases observed in intraperitoneal environments.
Catechol-tethered chitosan as a tissue-adhesive material
류지현 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Recently, catechol-tethered chitosan has attracted much attention as promising adhesive biomaterials applicable for hemostasis and surgical tissue adhesive in surgical procedures. Herein, we have synthesized and processed chitosan-tethered chitosan materials in various physical forms including hydrogels, (thin) films, sponges, and nanoparticles. The variety of physical states of catechol-tethered chitosan are expected to be usefully exploited for injectable drug delivery depots, tissue engineering hydrogels, underwater adhesives, tissue culture platforms, and anti-bleeding materials.
류지현,이해신 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
Phenol derivative-containing adhesive hydrogels has been widely recognized for potential biomedical applications, but conventional methods utilizing moderate/strong base, alkaline buffers, addition of oxidizing agents, or use of costly enzyme, have required alternative approaches for improved biocompatibility. In this study, we report a polymeric, enzyme-mimetic biocatalyst, hematin-grafted chitosan (chitosan-g-hem) that results in effective gelation without use of oxidizing agents or enzymes. Furthermore, the gelation occurs at a mild physiological condition. The use of chitosan-g-hem biocatalyst (0.01%, w/v) had excellent catalytic properties, forming rapid chitosan-catechol hydrogels within 5 minutes. In vivo adhesive force measurement demonstrated that the hydrogel formed by the chitosan-g-hem activity showed an increase in adhesion force (33.6 ± 5.9 kPa) compared with the same hydrogel formed by a pH-induced catechol oxidation (20.6 ± 5.5 kPa) in mouse subcutaneous tissue. Using the chitosan-g-hem biocatalyst, other catechol-functionalized polymers (hyaluronic acid-catechol and poly(vinyl alcohol)-catechol) also formed hydrogels, indicating that the chitosan-g-hem can be generally used as a polymeric catalyst for preparing catechol-containing hydrogels.
류지현,박혜진,정이영,한선규,신정혜,이수정,강민정,성낙주,강다원 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.4
Lipopolysaccharides (LPS) activate nuclear factor kappa B (NF-κB), a transcription factor that is involved in inflammatory response. The pathways that activate NF-κB can be modulated by phytochemicals derived from garlic. We recently demonstrated that aged red garlic extract (ARGE), a new formulation of garlic, decreases nitric oxide (NO) generation by upregulating of heme oxygenase-1 (HO-1) in RAW 264.7 cells activated by LPS. However, the effects of ARGE on LPS-induced NF-κB activation are unknown. This study was performed to evaluate whether ARGE regulates LPS-induced NO production by modulation of NF-κB activation in macrophages. The inhibition of NF-κB by Bay 11-7085, an inhibitor of NF-κB, decreased LPS-induced NO production. ARGE treatment markedly reduced LPS-induced NO production and NF-κB nuclear translocation. ARGE downregulated expression of inducible nitric oxide synthase (iNOS) and upregulated expression of HO-1, a cytoprotective and anti-inflammatory protein. However, Bay 11-7085 only reduced iNOS expression. The NO production and iNOS expressions upregulated by suppression of HO-1 were suppressed by treatment with ARGE and Bay 11-7085. These results show that ARGE reduces LPS-induced NO production in macrophages through inhibition of NF-κB nuclear translocation and HO-1 activation. Compared to Bay 11-7085, ARGE may enhance anti-inflammatory effects by controlling other anti-inflammatory signals as well as regulation of NF-κB.