• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1082-1083
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• 2006

Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of ${\beta}-TCP$ (Tri calcium phosphate) phase were detected. The maximum fracture toughness, $(1.27\;MPa.m^{1/2})$ was obtained in the sample sintered at $1100^{\circ}C$ and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.397-397
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• 2010

Bone is considered as hierarchically organized biocomposites of organic (collagen) and inorganic (hydroxyapatite) materials. The precise structural dependence between hydroxyapatite (HAp, $Ca_{10}(PO_4)_6(OH)_2)$ crystals and collagen fibril is critical to unique characteristics of bone. To meet those conditions and obtain optimal properties, it is essential to understand and control the initial growth mechanisms of hydroxyapatite at the molecular level, such as other nano-structured materials. In this study, collagen fibrils were prepared by adsorbing native type I collagen molecules onto hydrophobic surface. Hydrophobicity was introduced on the Si wafer surface by using PECVD (plasma enhanced chemical vapor deposition) method and cyclohexane as a precursor. Biomimetic nucleation and growth of HAp on the self-assembled collagen nanofibrils were occurred through incubation of the sample in SBF (simulated body fluid). Chemical and morphological evolution of HAp nanocrystals was investigated by surface-sensitive analytical techniques such as ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) and AFM (Atomic Force Microscopy) in the early growth stages (< 24 hrs). The very initial stages (< 12 hrs) of mineralization could be clearly demonstrated by ToF-SIMS chemical mapping of surface. In addition to ToF-SIMS and AFM measurement, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis were conducted to characterize the HAp layer in the late stages. This study is of great importance in the growth of real bone-like materials with a structure analogous to that of natural bones and the development of biomimetic nanomaterials.

• Advances in nano research
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• v.14 no.6
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• pp.507-519
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• 2023

Postsurgical infections are caused by implant-related pathogenic microorganisms that lead to graft rejection. Hence, an intrinsically antibacterial material is required to produce a biocompatible biomaterial with osteogenic properties that could address this major issue. Hence, this current research aims to make strontium-doped hydroxyapatite nanorods (SrHANRs) via an ethylene diamine tetraacetic acid (EDTA)-enable microwave mediated method using Anodontia alba seashells for biomedical applications. This investigation also perceives that EDTA acts as a soft template to accomplish Sr-doping and mesoporous structures in pure hydroxyapatite nanorods (HANRs). The X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis reveals the crystalline and mesoporous structures, and Brunauer-Emmett-Teller (BET) indicates the surface area of all the samples, including pure HANRs and doped HANRs. In addition, the biocidal ability was tested using various implant-related infectious bacteria pathogens, and it was discovered that Sr-doped HANRs have excellent biocidal properties. Furthermore, toxicity evaluation using zebrafish reports the non-toxic nature of the produced HANRs. Incorporating Sr²⁺ ions into the HAp lattice would enhance biocompatibility, biocidal activity, and osteoconductive properties. As a result, the biocompatible HANRs materials synthesized with Sr-dopants may be effective in bone regeneration and antibacterial in-built implant applications.

• Korean Journal of Materials Research
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• v.17 no.8
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• pp.408-413
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• 2007

Process of the hydroxyapapite(HA) precipitation on bioactive titanium metal prepared by NaOH in a modified-simulated body fluid(mSBF) was investigated by high resolution transmission electron microscope (HRTEM) attached with energy dispersive X-ray spectrometer(EDX). The amorphous titanate phase on titanium surface is form by NaOH treatment and an amorphous titanate incorporated calcium and phosphate ions in the liquid to form an amorphous calcium phosphate. With increasing of soaking time in the liquid, the HA particles are observed in amorphous calcium phosphate phase with a Ca/P atomic ratio of I.30. The octacalcium phosphate (OCP) structure is not detected in HRTEM image and electron diffraction pattern. After a long soaking time, the HA particles grow as needle-like shape on titanium surface and a large particle-like aggregates of needle-like substance were observed to form on titanium surface within needle-like shape. A long axis of needle parallels to c-direction of the hexagonal HA structure.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.213-214
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• 2009

A thin film hydroxyapatite (HA) films was deposited on anodized titanium by RF sputtering method. The anodized titanium enhanced the biocompatibility of the Ti and the bioactivity was improved further by the HA deposited on the anodized Ti. $TiO_2$ layer with $0.2{\sim}0.5{\mu}$ diameter pore size was formed on the Ti surface by anodization. Anodized $TiO_2$ layer analysis HA film deposited, oxide pore size and number decreased compared with non-HA deposited surface. The corrosion resistance of HA deposited/anodized Ti was higher than that of the non-treatment Ti alloy in Hank's solution, indicating better protective effect. From the results of cell culture using MTT assays, the best cell proliferation showed in HA deposited surface after anodization of Ti surfaces compared with another surface treatment.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.146.2-146.2
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• 2007

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.2
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• pp.81-83
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• 2008

The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, two different types, cylinder and scaffold, of implantable Drug Delivery System (DDS) were fabricated using Nano Composite Deposition System (NCDS), one of the RP systems. The anti-cancer drug (5-fluorouracil, 5-FU), biodegradable polymer (PLGA(85: 15)), and bio ceramic (Hydroxyapatite, HA) were used to form drug-polymer composite material. Both types of DDS were evaluated in vivo environment for two weeks. For evaluation, the cumulative drug release and shape stability were measured. Test results showed that the scaffold DDS provide higher cumulative drug release and has better stability than cylinder DDS.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.139-140
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• 2015

Zn/HA coating on the Ti-xNb alloys after nanotube formation for dental lmplant was researched using various experimental methods. Due to g ood biocompatibility and osteoconductivity, hydroxyapatite (HA) coating s on metallic biomedical implants were widely employed in orthopedic and dental applications. To improve biocompatibilities, Zinc (Zn) plays very important roles in the bone formation and immune reg ulations. The nanotube formed Zn-HA films were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.206-210
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• 2018

Two kinds of bioactive glass were coated on the Ti6Al4V alloy by the enameling technique. In order to reduce the thermal stress due to the difference in expansion coefficient with the alloy with the secondary coating forming hydroxyapatite, the difference in expansion coefficient between the alloy and the two glasses was adjusted at $2{\times}10^{-6}/^{\circ}C$ intervals. FE-SEM and EDS analysis showed that good adhesion was formed between the Ti6Al4V alloy and the primary coating by diffusion bonding. After immersion in SBF solution, it was confirmed from FT-IR that hydroxycarbonate apatite formed in the secondary coating was not different from bulk bioactive glass.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.78-78
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• 2017

Pure Titanium and alloy have been widely used in dental implants and orthopedics due to their excellent mechanical properties, biocompatibility and corrosion resistance. However, due to the biologically inactive nature of Ti metal implants, it cannot bind to the living bone immediately after transplantation into the body. In order to improve the bone bonding ability of titanium implants, many attempts have been made to alter the structure, composition and chemical properties of titanium surfaces, including the deposition of bioactive coatings. The PEO method has the advantages of short experiment time and low cost. These advantages have attracted attention recently. Recently, many metal ions such as silicon, magnesium, zinc, strontium, and manganese have received attention in this field due to their impact on bone regeneration. Silicon (Si) in particular has been found to be essential for normal bone and cartilage growth and development. Zinc (Zn) plays very important roles in bone formation and immune system regulation and promotes bone metabolism and growth. Manganese (Mn) is an essential trace metal found in all tissues and is required for normal amino acid, lipid, protein and carbohydrate metabolism. The objective of this work was research on the corrosion behavior of Si, Zn and Mn-doped hydroxyapatite on the PEO-treated surface. Anodized alloys was prepared at 270V~300V voltage in the solution containig Zn, Si, and Mn ions. Ion release test was carried out using potentidynamic and AC impedance method in 0.9% NaCl solution. The surface characteristics of PEO treated Ti-6Al-4V alloy were investigated using XRD, FE-SEM, AFM and EDS.