Seongnam, South Korea
Seongnam, South Korea

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The present invention relates to a carrier for growth factor related to regeneration of bone tissues that is capable of arbitrarily controlling the delivery rate of growth factors related to bone regeneration and thus especially applicable to a bone void filler in the fields of the dental or orthopedic applications. The carrier for controlling the delivery rate of the growth factor in the present invention is composed of a hyaluronic acid hydrogel having a distribution of interconnected pores and a calcium phosphate microsphere being distributed in the pores of the hyaluronic acid hydrogel. The calcium phosphate microsphere having a porosity suitable for delivery of the growth factor is positioned into the pores of the cross-linked hyaluronic acid hydrogel to complete the carrier.


Kim D.W.,Seoul National University | Cho I.-S.,Seoul National University | Kim J.Y.,National Renewable Energy Laboratory | Jang H.L.,Seoul National University | And 6 more authors.
Langmuir | Year: 2010

The noble synthesis method for hydroxyapatite (HAp) nanoparticles was exploited using a fairly simple reaction of Ca(OH)2 and H 3PO4, which does not generate residual harmful anions and consequently does not need an additional washing process. HAp nanoparticles were found to yield from dicalcium phosphate dehydrate (DCPD) as the only intermediate phase, which was monitored by in situ observation study using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), 1H and 31P magic-angle spinning (MAS) NMR. Furthermore, we found that the phase evolution of HAp was preceded by heteronucleation of HAp onto the DCPD surface. The combination of scanning electron microscopy (SEM) and inductively coupled plasma atomic emission spectroscopy (ICP-ES) analysis gave more information on the HAp crystallization process, which was found to be retarded by the residual Ca(OH)2 and slow diffusion process of Ca ions into the interface between HAp and DCPD. These results demonstrate that the synthesis of pure HAp nanoparticles with high throughput can be achieved by controlling the residual Ca(OH)2 and diffusion process of Ca ions. © 2009 American Chemical Society.


PubMed | BioAlpha Inc., Chonnam National University and Sunchon National University
Type: | Journal: Journal of the mechanical behavior of biomedical materials | Year: 2015

In this study, we aimed to evaluate the mechanical effects of different stent linker designs on in-stent restenosis in porcine coronary arteries. We fabricated stents with an open-cell structure composed of nine main cells and three linker structures in model 1 (I-type), model 2 (S-types) and model 3 (U-types)) as well as Model 4, which is similar to a commercial bare metal stent design. The stent cells were 70 mm thick and wide, with a common symmetrical wave pattern. As the radial force increased, the number of main cells increased and the length of linker decreased. Radial force was higher in model 1, with a linear I-linker, than in models with S- or U-linkers. The flexibility measured by three-point bending showed a force of 1.09 N in model 1, 0.35 N in model 2, 0.19 N in model 3, and 0.31 N in model 4. The recoil results were similar in all models except model 4 and were related to the shape of the main cells. The foreshortening results were related to linker shape, with the lowest foreshortening observed in model 3 (U-linker). Restenosis areas in the porcine restenosis model 4 weeks after implantation were 35.4 8.39% (model 1), 30.4 7.56% (model 2), 40.6 9.87% (model 3) and 45.1 12.33% (model 4). In-stent restenosis rates measured by intravascular ultrasound (IVUS) and micro-computed tomography (micro-CT) showed similar trends as percent area stenosis measured by micro-CT. Model 2, with optimized flexibility and radial force due to its S-linker, showed significantly reduced restenosis in the animal model compared to stents with different linker designs. These results suggest that the optimal stent structure has a minimum radial force for vascular support and maximum flexibility for vascular conformability. The importance of the effects of these differences in stent design and their potential relationship with restenosis remains to be determined.


Lee J.H.,Seoul National University | Ryu M.Y.,BioAlpha Inc. | Baek H.-R.,Seoul National University | Lee H.-K.,Seoul National University | And 6 more authors.
Artificial Organs | Year: 2014

Bone formation in tooth defect areas and the osseointegration of dental implants are very important for successful dental implant surgery. The aim of the present study was to assess the strengthening effect of a β-TCP microsphere-hydrogel composite containing recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone healing and implant osseointegration. The molars and premolars on the left and right sides of the maxilla were extracted from six male minipigs, and dental implants were placed using either the β-TCP microsphere-hydrogel carrier alone or the carrier loaded with rhBMP-2 (500μg). The animals were kept alive for a further 8 weeks. The molars and premolars from the left and the right sides of the mandibles of another six minipigs were extracted, and the animals were kept alive for 4 weeks. Two 5-mm-diameter bone defects were then made on both sides of the mandible. The defects were filled with saline, β-TCP microsphere-hydrogel carrier, or the carrier loaded with rhBMP-2 (300μg), and dental implant fixtures were inserted. The animals were kept alive for a further 4 weeks. Bone formation was examined using plane radiographs, micro-CT, and the histology of undecalcified specimens. The group treated with the rhBMP-2-loaded carrier composite showed a significantly higher percentage bone volume and a greater trabecular thickness for the newly formed bone in the tooth defect areas when compared to the group treated with the carrier alone. The rhBMP-2 group had a significantly higher osseointegration, a larger percentage bone volume, greater trabecular thickness in the newly formed bone in tooth defect areas, a larger newly formed bone fraction in the fixture pitch, and a greater number of newly formed trabecular bones when compared to the other groups. We confirmed that the rhBMP-2-loaded carrier composite promotes new bone formation after tooth extraction and strengthens osseointegration of dental fixtures by improving the degree of osseointegration around the dental implant fixture. © 2014 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.


Maeng J.H.,Advanced Therapeutics Research Center | Bang B.W.,Inha University | Lee E.,Advanced Therapeutics Research Center | Kim J.,BioAlpha Inc. | And 4 more authors.
Journal of Materials Science: Materials in Medicine | Year: 2014

The gastrointestinal (GI) endoscopy has become a standard diagnostic tool for GI ulcers and cancer. In this study we studied endoscopic application of epidermal growth factor-containing chitosan hydrogel (EGF-CS gel) for treatment of GI ulcer. We hypothesized that directional ulcer-coating using EGF-CS gel via endoscope would precipitate ulcer-healing. EGF-CS gel was directly introduced to the ulcer-region after ulceration in acetic acid-induced gastric ulcer (AAU) and mucosal resection-induced gastric ulcer (MRU) rabbit and pig models. The ulcer dimensions and mucosal thicknesses were estimated and compared with those in the control group. Healing efficacy was more closely evaluated by microscopic observation of the ulcer after histological assays. In the AAU model, the normalized ulcer size of the gel-treated group was 2.3 times smaller than that in the non-treated control group on day 3 after ulceration (P < 0.01). In the MRU model, the normalized ulcer size of the gel-treated group was 5.4 times smaller compared to that in the non-treated control group on day 1 after ulceration (P < 0.05). Histological analysis supported the ability of EGF-CS gel to heal ulcers. The present study suggests that EGF-CS gel is a promising candidate for treating gastric bleeding and ulcers. © 2013 Springer Science+Business Media New York.


Provided is a portable vacuum generator that can effectively save battery power of a vacuum pump for absorbing exudates from a suction head that is connected to a tube, and a medical suction device using the same. The medical suction device includes: a connection tube whose one end is connected to a connector of the suction head; and a vacuum generator including a vacuum pump that is connected to the other end of the connection tube and having a motor for generating negative pressure, and a vacuum pump controller that controls a power supply for the vacuum pump so as to maintain a vacuum state, in which the vacuum pump controller blocks the power supply for the vacuum pump until pressure of the vacuum pump falls down to preset minimum pressure in the case that the current pressure that is applied to the vacuum pump reaches preset maximum pressure, and drives the vacuum pump until pressure of the vacuum pump reaches the preset maximum pressure in the case that the current pressure falls down to the preset minimum pressure.


Disclosed herein is a method for preparing an aqueous solution of high-concentration calcium phosphate, the method comprising the steps of: preparing an acidic aqueous solution using an acidic chelating agent; and dissolving a calcium phosphate-based compound in the acidic aqueous solution, and then adding a pH-adjusting agent to the acidic aqueous solution to adjust the pH of the acidic aqueous solution. The disclosed aqueous solution does not form a precipitate after neutralization so that it can be used in various calcium-containing products, including foods, drugs, or quasi-drugs.


Patent
BioAlpha Inc. | Date: 2013-02-27

Disclosed is a vascular stent which is inserted inside a blood vessel. The disclosed vascular stent comprises: a first coating film comprising a restenosis inhibiting drug provided on the outside surface of the stent strut; and a second coating film comprising an internal-capsule cellularization promoting drug provided on the inside surface of the stent strut. In this way, restenosis and thrombosis can be prevented from occurring inside the stent.


Provided is a portable vacuum generator that can effectively save battery power of a vacuum pump for absorbing exudates from a suction head that is connected to a tube, and a medical suction device using the same. The medical suction device includes: a connection tube whose one end is connected to a connector of the suction head; and a vacuum generator including a vacuum pump that is connected to the other end of the connection tube and having a motor for generating negative pressure, and a vacuum pump controller that controls a power supply for the vacuum pump so as to maintain a vacuum state, in which the vacuum pump controller blocks the power supply for the vacuum pump until pressure of the vacuum pump falls down to preset minimum pressure in the case that the current pressure that is applied to the vacuum pump reaches preset maximum pressure, and drives the vacuum pump until pressure of the vacuum pump reaches the preset maximum pressure in the case that the current pressure falls down to the preset minimum pressure.


The present invention relates to a carrier for growth factor related to regeneration of bone tissues that is capable of arbitrarily controlling the delivery rate of growth factors related to bone regeneration and thus especially applicable to a bone void filler in the fields of the dental or orthopedic applications. The carrier for controlling the delivery rate of the growth factor in the present invention is composed of a hyaluronic acid hydrogel having a distribution of interconnected pores and a calcium phosphate microsphere being distributed in the pores of the hyaluronic acid hydrogel. The calcium phosphate microsphere having a porosity suitable for delivery of the growth factor is positioned into the pores of the cross-linked hyaluronic acid hydrogel to complete the carrier.

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