• 한국결정성장학회지
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• 제31권5호
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• pp.203-211
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• 2021

옥타칼슘포스페이트(OCP, Ca₈H₂(PO₄)₆·5H₂O)는 골전도성과 생체적합성을 가진 생분해성 인산칼슘계 재료 중 하나이다. 기질세포를 자극하여 조골세포로 분화하는 성질을 가지고 있어 빠른 골형성 및 재흡수되는 장점을 가지고 있다. 그러나 OCP가 체내에 삽입되면 분말 사이의 약한 응집력으로 인해 지지체의 형태를 유지하지 못하고 빠르게 분해된다. 반면, OCP와 유사한 결정구조를 갖는 수산화인회석(HA, Ca₁₀(PO₄)₆(OH)₂)은 골결손이 회복된 이후까지도 분해되지 않고 체내에 남아있다. 이 연구에서는 SBF(simulated body fluid) 용액에 HA 첨가량이 다른 OCP/HA disc을 침적한 후 기간에 따른 Weight loss, pH 변화 및 미세구조 변화의 측면에서 분해거동을 조사하였다. 그 결과 OCP/HA disc는 HA 함량에 관계없이 2주 동안 형태를 유지하였다. 특히, 40HA 시편의 표면이 균일하게 용해되는 양상을 보였고 SBF 용액 침적 후 7일 후부터 disc의 표면에 CDHA(calcium deficient hydroxyapatite)가 형성되었다. 이러한 결과는 40HA 시편이 골결손부의 회복을 위한 지지체로 적합하다는 것을 보여준다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1089-1090
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• 2006

Biomimetic apatite deposition behaviors on Zr-1Nb and Ti-6Al-4V plate with various surface conditions were examined. Both alloys were polished with abrasive papers to have different roughness and some of them were treated in NaOH before exposition in simulated body fluid. NaOH treatment was found to enhance the deposition rate of apatite on Ti-6Al-4V significantly. On the other hand, the deposition rate of Zr-1Nb was not influenced by NaOH treatment. Without NaOH treatment, the polished Zr-1Nb with abrasive paper was found to induce more apatite nucleation than the polished Zr-6Al-4V.

• 한국재료학회지
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• 제20권6호
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• pp.312-318
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• 2010

Multilayer Poly methyl methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates were fabricated using electrospinning and in vitro investigations were carried out for pre-clinical biocompatibility studies. The initial cellular cytotoxicity of the methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using fibroblast-like L-929 cells. Cellular adhesion and differentiation studies were carried out using osteoblast-like MG-63 cells. As simulated body fluid (SBF) contains the same ionic concentration of body fluid and any bioactive material tends to deposit bone-like apatite on the samples surfaces into the SBF, in vitro bioactivity of the multilayer bone plates were investigated using SBF. We also studied the internal organization and tensile strength of the multilayer PMMA/PVA bone plates using micro-computed topography (${\mu}$-CT) and universal testing instrument (UTI, Korea) respectively. The cellular cytotoxicity study with MTT confirmed that the cellular viability was 78 to 90% which indicates good cyto-compatibility. Scanning electron microscopic findings revealed a good attachment and adhesion phenomenon of MG-63 cells onto the surfaces of the samples. Cellular differentiation studies also showed that osteogenic differentiation was switched on in a timely manner and affirmed along with that of the control group. Bone-like apatite formation on the surfaces was confirmed within 14 days of SBF incubation. Initial organizations of the multilayer PMMA/PVA bone plates were characterized as dense and uniform. The tensile strength of the post-pressing electronspun mat was higher than that of the pre-electronspun mat. These results suggest that a multilayer PMMA/PVA bone plate system is biocompatible, bioactive and a very good alternative bone plate system.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1257-1258
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• 2006

Biomimetic apatite deposition behaviors and mechanical performance for as-rolled and annealed Ni-Ti plates were investigated . A good biomimetic apatite formation and excellent mechanical performance of Ni-Ti suggests that Ni-Ti can be an excellent candidate material as orthopedic implants.

• 한국세라믹학회지
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• 제42권11호
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• pp.770-776
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• 2005

Hardening and hydroxyapatite(HAp) formation behavior of the bioactive cements in the system of $CaO-SiO_{2}-P_{2}O_{5}$ glasses and the corresponding glass-ceramics were studied. DCPD (Dicalcium Phosphate Dihydrate: $CaHPO_4{\cdot}2H_2O$) and DCPA (Dicalcium Phosphate Anhydrous: $CaHPO_4$) were developed when the prepared glass and glass-ceramic powders were mixed with three different solutions. The DCPD and DCPA transformed to HAp when the cement was soaked in Simulated Body Fluid (SBF), and this HAp formation strongly depended on the releasing capacity of $Ca^{2+}$ ions from the cements. The glass-ceramic containing apatite showed fast setting, but no HAp formation was observed because no $Ca^{2+}$ ions were released from this glass-ceramics. The compressive strength of the cements increased with reaction time in SBF until all DCPD and DCPA transformed to HAp.

• Corrosion Science and Technology
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• 제15권2호
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• pp.43-53
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• 2016

In this study, electrochemical impedance spectroscopy (EIS) was used to examine the changes in the electrochemical properties of biodegradable pure magnesium implanted into Sprague-Dawley rats for three days. The in vivo test results were compared with those of the in vitro tests carried out in Hank's, dilute saline and simulated body fluid (SBF) solutions. The in vitro corrosion rates were 20~1700 fold higher, as compared to the in vivo corrosion rates. This discrepancy is caused by biomolecule adsorption on the surface, which prevents the transport of water into the magnesium surface on in vivo testing. Among the in vitro experimental conditions, the corrosion rate in SBF solution had the least difference from the in vivo implanted specimen.

• 한국재료학회지
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• 제17권11호
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• pp.622-627
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• 2007

Porous poly(e-caprolactone) (PCL) scaffolds were fabricated by salt leaching method. The PCL scaffolds were treated with aqueous NaOH for 0h, 2h, 4h, 8h, and 12h at $40^{\circ}C$. The NaOH-treated PCL scaffolds were dipped in $CaCl_2$ and $K_2HPO_4{\cdot}_3H_2O$ solution alternately three times to induce apatite nuclei onto the surface of the scaffolds. The NaOH-treated PCL scaffolds were immersed into SBF solution for 1day to grow the apatite. The apatite formation were investigated as a fuction of NaOH treatment time. The hydrophilicty and surface area of the PCL scaffolds were increased with NaOH-treatment time. The NaOH-treated PCL scaffolds were successfully formed a dense and uniform bone-like apatite layer after immersion for 1 day in SBF solution.

• 한국재료학회지
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• 제16권11호
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• pp.676-680
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• 2006

The biodegradable $\beta$-tricalcium phosphate ($\beta$-TCP)/poly(lactide-co-glycolide) (PLGA) composites were synthesized by in situ polymerization with microwave energy. The degradation behavior of $\beta$-TCP/PLGA composite was investigated by soaking in simulated body fluid (SBF) for 4 weeks. The molecular weight of the $\beta$-TCP/PLGA composites decreased with soaking time until week 2, whereas the loss rate of molecular weight reduced after week 2. The incubation time was needed for the degradation of the $\beta$-TCP, indicating that the $\beta$-TCP should be detached from the PLGA matrix and then degraded into SBF solution. The studies of mass loss of the composites with the soaking time revealed that the degradation behavior of PLGA would be processed with the transformation from the polymer to the oligomer followed by the degradation. Morphological changes, whisker-like, due to transformation and degradation of polymer in the composites were observed after week 2. On the basis of the results, it found that the degradation behavior of $\beta$-TCP/PLGA composites was influenced by the $\beta$-TCP content in the composites and the degradation rate of the composites could be controlled by the initial molecular weight of PLGA in the composites.

• 한국결정성장학회지
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• 제32권5호
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• pp.183-190
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• 2022

다이옵사이드(CaMgSi₂O₆)는 생체활성이 높을 뿐만 아니라 우수한 기계적 성질도 보유한 물질로 알려져 있다. 본 연구에서는 지르코니아 세라믹스의 생체활성을 향상시키기 위하여 지르코니아 기판 표면에 다이옵사이드를 솔젤법으로 코팅하고 in vitro 시험을 통해 지르코니아 기판의 생체활성 증진을 고찰하였다. 코팅용 다이옵사이드 솔은 Ca(NO₃)₂·H₂O, MgCl₂·H₂O 및 Si(OC₂H₅)₄를 각각의 몰비로 에탄올에 용해한 후 가수분해시켜 제조하였다. 다이옵사이드 코팅에 의한 생체활성 증진을 고찰하기 위하여 SBF 용액 내에서 in vitro 시험을 진행하였는데, 침적초기에는 주로 코팅층 다이옵사이드 입자들의 표면용해가 관찰되었고, 새로운 하이드록시아파타이트 입자의 석출은 14일 침적시편에서 주로 관찰되었다. In vitro 시험 시 SBF(Simulated Body Fluid) 용액에 대한 다이옵사이드 코팅층의 용해와 기판 표면에 석출되는 하이드록시아파타이트 층의 양과 형태는 코팅횟수와 코팅층 두께에 의존하였다.

• The Korean Journal of Ceramics
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• 제4권4호
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• pp.336-339
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• 1998

Bioactive titanium metal can be prepared by simple 5M-NaOH treatment and subsuquent heat treatment at $600^{\circ}C$ to form an amorphous sodium titanate on its surface. In the present study, mechanism of apatite formation on the titanium metal was investigated by examining its surface compositional and structural changes in a simulated body fluid. The apatite formation on the metal was found to proceed in the sequence of 1)$Na^+$ ion release from the sodium titanate to form hydrated titania abundant in Ti-OH groups, 2) early and selective binding of calcium ions with the Ti-OH groups to form a calcium titanate, and 3) late binding of phosphate ions to make apatite nucleation and growth. This indicates that Ti-OH groups do not directly induce the apatite nucleation, but via formation of a calcium titanate.