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Kim, Kangmin,Park, Suhyung,Park, Jeong Hwan,Cho, Won-Sang,Kim, Hyoun-Ee,Lee, Sung-Mi,Kim, Jeong Eun,Kang, Hyun-Seung,Jang, Tae-Sik The Korean Neurosurgical Society 2021 Journal of Korean neurosurgical society Vol.64 No.6
Objective : Biodegradable poly-L-lactic acid (PLLA) with a highly biocompatible surface via tantalum (Ta) ion implantation can be an innovative solution for the problems associated with current biodegradable stents. The purpose of this study is to develop a Taimplanted PLLA stent for clinical use and to investigate its biological performance capabilities. Methods : A series of in vitro and in vivo tests were used to assess the biological performance of bare and Ta-implanted PLLA stents. The re-endothelialization ability and thrombogenicity were examined through in vitro endothelial cell and platelet adhesion tests. An in vivo swine model was used to evaluate the effects of Ta ion implantation on subacute restenosis and thrombosis. Angiographic and histologic evaluations were conducted at one, two and three months post-treatment. Results : The Ta-implanted PLLA stent was successfully fabricated, exhibiting a smooth surface morphology and modified layer integration. After Ta ion implantation, the surface properties were more favorable for rapid endothelialization and for less platelet attachment compared to the bare PLLA stent. In an in vivo animal test, follow-up angiography showed no evidence of in-stent stenosis in either group. In a microscopic histologic examination, luminal thrombus formation was significantly suppressed in the Ta-implanted PLLA stent group according to the 2-month follow-up assessment (21.2% vs. 63.9%, p=0.005). Cells positive for CD 68, a marker for the monocyte lineage, were less frequently identified around the Ta-implanted PLLA stent in the 1-month follow-up assessments. Conclusion : The use of a Ta-implanted PLLA stent appears to promote re-endothelialization and anti-thrombogenicity.
Kim, Hyoun-Ee,Kim, Hae-Won,Jang, Jun-Hyeog John Wiley Sons, Ltd. 2009 Journal of Peptide Science Vol.15 No.1
<P>Heparin/heparan sulfate (HS) plays a key role in cellular adhesion. In this study, we utilized a 12-mer random Escherichia coli cell surface display library to identify the sequence, which binds to heparin. Isolated insert analysis revealed a novel heparin-binding peptide sequence, VRRSKHGARKDR, designated as HBP12. Our analysis of the sequence alignment of heparin-binding motifs known as the Cardin–Weintraub consensus (BBXB, where B is a basic residue) indicates that the HBP12 peptide sequence contains two consecutive heparin-binding motifs (i.e. RRSK and RKDR). SPR-based BIAcore technology demonstrated that the HBP12 peptide binds to heparin with high affinity (K<SUB>D</SUB> = 191 nM). The HBP12 peptide is found to bind the cell surface HS expressed by osteoblastic MC3T3 cells and promote HS-dependent cell adhesion. Moreover, the surface-immobilized HBP12 peptide on titanium substrates shows significant increases in the osteoblastic MC3T3-E1 cell adhesion and proliferation. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.</P>
Kim, Hae-Won,Kim, Hyoun-Ee,Salih, Vehid,Knowles, Jonathan C. Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of biomedical materials research. Part A Vol.a74 No.3
<P>Titanium (Ti) surface was coated with hydroxyapatite (HA) films via the sol-gel method. The coating properties, such as crystallinity and surface roughness, were controlled and their effects on the osteoblast-like cell responses were investigated. The film crystallinity was controlled with different heat treatment temperatures (400, 500, and 600°C): Also the surface roughness was changed by using different heating rates (1 and 50°C/min). The obtained sol-gel films had a dense and homogeneous structure with a thickness about 1 μm. The film heat-treated at higher temperature had enhanced crystallinity (600 > 500 ≫ 400°C), while retaining similar surface roughness. When heat-treated rapidly (50°C/min), the film became quite rough, with roughness parameters being much higher (4–6 times) than that obtained at a low heating rate (1°C/min). The dissolution rate of the film decreased with increasing crystallinity (400 ≫ 500 > 600°C), and the rougher film had slightly higher dissolution rate. The attachment, proliferation, and differentiation behaviors of human osteosarcoma HOS TE85 cells were affected by the properties of the films. On the films with higher crystallinity (heat treated over 500°C), the cells attached and proliferated well and expressed alkaline phosphatase (ALP) and osteocalcin (OC) to a higher degree as compared to the poorly crystallized film (heat treated at 400°C). On the rough film, the cell attachment was enhanced, but the ALP and OC expression levels were similar as compared to the smooth films. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005</P>
Nanofiber generation of hydroxyapatite and fluor-hydroxyapatite bioceramics
Kim, Hae-Won,Kim, Hyoun-Ee Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of biomedical materials research. Part B, Vol.b77 No.2
<P>In this study, we produced hydroxyapatite (HA) and fluor-hydroxyapatite (FHA) bioceramics as a novel geometrical form, the nanoscale fiber, for the biomedical applications. Based on the sol-gel precursors of the apatites, an electrospinning technique was introduced to generate nanoscale fibers. The diameter of the fibers was exploited in the range of a few micrometers to hundreds of nanometers (1.55 μm–240 nm) by means of adjusting the concentration of the sols. Through the fluoridation of apatite, the solubility of the fiber was tailored and the fluorine ions were well released from the FHA. The HA and FHA nanofibers produced in this study are considered to find potential applications in the biomaterials and tissue engineering fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006</P>
Kim, Sae-Mi,Kang, Min-Ho,Kim, Hyoun-Ee,Lim, Ho-Kyung,Byun, Soo-Hwan,Lee, Jong-Ho,Lee, Sung-Mi Elsevier 2017 Materials science & engineering. C, Materials for Vol.81 No.-
<P><B>Abstract</B></P> <P>The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(<SMALL>L</SMALL>-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLLA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLLA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLLA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLLA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A HA/PLLA micro-textured coating layer was successfully created onto a Mg implant. </LI> <LI> The bioactive HA micro-dots were surrounded by a flexible PLLA) polymer. </LI> <LI> An excellent stability under the mechanical strains was achieved for the coated implant. </LI> <LI> The excellent corrosion resistance and the biocompatibility in vitro were preserved. </LI> </UL> </P>
Kim, Hae-Won,Lee, Eun-Jung,Jun, In-Kook,Kim, Hyoun-Ee,Knowles, Jonathan C. Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of Biomedical Materials Research Part B Vol. No.
<P>Phosphate-based glass (P-glass) and poly(ε-caprolactone) (PCL) composites were fabricated in a sheet form by solvent extraction and thermal pressing methods, and the antibiotic drug Vancomycin was loaded within the composites for use as a hard-tissue regenerative. The degradation and drug-release rate of the composites in vitro were tailored by modifying the glass composition: 0.45P<SUB>2</SUB>O<SUB>5</SUB>-xCaO-(0.55-x)Na<SUB>2</SUB>O, where x = 0.2, 0.3, 0.4, and 0.5. Compared to pure PCL, all the P-glass/PCL composites degraded to a higher degree, and the composite with lower-CaO glass showed a higher material loss. This was attributed mainly to the dissolution of the glass component. The glass dissolution also increased the degradation of PCL component in the composites. The Vancomycin release from the composites was strongly dependent on the glass composition. Drug release in pure PCL was initially abrupt and flattened out over a prolonged period. However, glass/PCL composites (particularly in the glass containing higher-CaO) exhibited a reduced initial burst and a higher release rate later. Preliminary cell tests on the extracts from the glass/PCL composites showed favorable cell proliferation, but the level was dependent on the ionic concentration of the extracts. The cell proliferation on the diluted extracts from the composite with higher-CaO glass was significantly higher than that on the blank culture dish. These observations confirmed that the P-glass/PCL composites are potentially applicable for use as hard-tissue regeneration and wound-healing materials because of their controlled degradation and drug-release profile as well as enhanced cell viability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005</P>
Kim, Hae-Won,Knowles, Jonathan C.,Kim, Hyoun-Ee Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of Biomedical Materials Research Part B Vol. No.
<P>Gelatin–hydroxyapatite (HA) nanocomposite porous scaffolds were fabricated biomimetically, and their feasibility as a drug-delivery carrier for tissue-regeneration and wound-healing treatments was addressed. The composite sols were prepared by the precipitation of HA up to 30 wt % within a gelatin solution with the use of calcium and phosphate precursors, and the porous scaffold was obtained by casting the sols and further freeze drying. The obtained bodies were crosslinked with carbodiimide derivatives to retain chemical and thermal integrity. The apatite precipitates were observed to be a poorly crystallized carbonate-substituted HA. The nanocomposite scaffolds had porosities of ∼ 89–92% and exhibited a bimodal pore distribution, that is, the macropores (∼ 300–500 μm) of the framework structure, and micropores (∼ 0.5–1 μm) formed on the framework surface. Transmission electron microscopy (TEM) observation revealed the precipitation of highly elongated HA nanocrystals on the gelatin network. The well-developed porous structure and organized nanocomposite configurations were in marked contrast to the directly mixed gelatin–HA powder conventional composites. For drug-release tests, tetracycline, an antibiotic drug, was entrapped within the scaffold, and the drug-release profile was examined with processing parameters, such as HA amount in gelatin, crosslinking degree, and initial drug addition. The drug entrapment decreased with increasing HA amount, but increased with increasing crosslinking degree and initial drug addition. The crosslinking of the gelatin was the prerequisite to sustaining and controlling the drug releases. Compared to pure gelatin, the gelatin–HA nanocomposites had lower drug releases, because of their lower water uptake and degradation. All the nanocomposite scaffolds released drugs in proportion to the initial drug addition, suggesting their capacity to deliver drugs in a controlled manner. Based on the findings of the well-developed morphological feature and controlled drug-release profile, the gelatin–HA nanocomposite porous scaffolds are suggested to be potentially useful for hard-tissue regeneration. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005</P>