• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.63-67
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• 2007

Biodegradable cationic poly(ester-amide) polymers were synthesized by double-monomer method, that showed excellent solubility in many organic solvents and water. Different degradation patterns were obtained by the regulation of monomer ratios and overall long period of time of DNA protection up to 12 days was shown by PicoGreen reagent assay. Good transfection profiles in the presence of serum and very low toxicity on mammalian cells may allow these polymers to become suitable for long-term gene delivery systems and therapeutic applications.

• 한국정밀공학회지
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• 제24권4호
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• pp.138-146
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• 2007

Some biodegradable polymers and other materials such as hydrogels have shown the promising potential for surgical applications. Post surgical adhesion caused by the natural consequence of surgical wound healing results in repeated surgery and harmful effects. Recently, scientists have developed absorbable anti-adhesion barriers that can protect a tissue from adhesion in case they are in use; however, they are dissolved when no longer needed. Although these approaches have been attempted to fulfill the criteria for adhesion prevention, none can perfectly prevent adhesions in all situations. Overall, we developed a new method to fabricate an anti-adhesion membrane using biodegradable polymer and hydrogel. It employed a highly accurate three-dimensional positioning system with pressure-controlled syringe to deposit biopolymer solution. The pressure-activated microsyringe was equipped with fine-bore nozzles of various inner-diameters. This process allowed that inner and outer shapes could be controlled arbitrarily when it was applied to a surgical region with arbitrary shapes. In order to fulfill the properties of the ideal barriers f3r preventing postoperative adhesion, we adopted the pre-mentioned method combined with surface modification with the hydrogel coating by which anti-adhesion property was improved.

• 폴리머
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• 제31권3호
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• pp.201-205
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• 2007

폴리락타이드, 폴리글리콜라이드, 및 글리콜라이드-락타이드 공중합체(PLGA)와 같은 생분해성 고분자들은 쉬운 약물방출량 조절과 부산물독성이 없이 지지체의 완벽한 분해과 좋은 생체적합성을 갖고 있다. 그러나 PLGA는 in vitro 실험에서의 괴상침식, 과도한 초기방출 후의 방출량이 감소하는 단점을 갖고 있다. 본 연구에서 PLGA 재결정 분말은 진공건조법을 이용하여 제조하였으며 1,3-bis(2-chloroethyl)-1-nitro-sourea(BCNU, carmustine)가 함유된 PLGA 웨이퍼의 방출거동을 알아보았으며 동시에 수용성 첨가제를 넣어 약물의 방출거동을 알아보고자 하였다. 진공건조법으로 재결정한 PLGA 웨이퍼가 일반방법으로 제조한 PLGA 웨이퍼보다 수분흡수율 감소와 웨이퍼 자체 초기의 분해 속도 감소로 인하여 초기 방출량이 감소하고 지속적 방출거동을 가지는 것을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제34권3호
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• pp.111-116
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• 2013

Finite element analysis(FEA) has been extensively applied in the analyses of biomechanical properties of stents. Geometrically, a closed-cell stent is an assembly of a number of repeated unit cells and exhibits periodicity in both longitudinal and circumferential directions. This study concentrates on various parameters of the FEA models for the analysis of drug-eluting biodegradable polymeric stents for application to the treatment of coronary artery disease. In order to determine the mechanical characteristics of biodegradable polymeric stents, FEA was used to model two different types of stents: tubular stents(TS) and helicoidal stents(HS). For this modeling, epigallocatechin-3-O-gallate (EGCG)-eluting poly[(L-lactide-co-${\varepsilon}$-caprolactone), PLCL] (E-PLCL) was chosen as drug-eluting stent materials. E-PLCL was prepared by blending PLCL with 5% EGCG as previously described. In addition, the effects of EGCG blending on the mechanical properties of PLCL were investigated for both types of stent models. EGCG did not affect tensile strength at break, but significantly increased elastic modulus of PLCL. It is suggested that FEA is a cost-effective method to improve the design of drug-eluting biodegradable polymeric stents.

• 폴리머
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• 제24권2호
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• pp.141-148
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• 2000

Polycaprolactone (PCL)을 base로 하는 효과적인 compost 필름을 만들기 위하여 옥수수전분을 블렌딩한 뒤 기계적 특성과 미생물에 의한 생분해도를 조사하였다. 비상용성을 보이는 옥수수전분/PCL 블렌드에 대한 상용화제로는 2-hydroxyethylmethacrylate (HEMA)-PCL macromer를 옥수수전분에 그래프팅시킨 공중합체를 사용하였는데 옥수수전분에 대한 HEMA의 그래프팅율이 가장 높은 것과 가장 낮은 것을 선택하여 일정한 조성의 $\varepsilon$-caprolactone에 그래프팅시킨 상용화제들의 상용화 효과를 비교하였다. 상용화제를 함유한 옥수수전분/PCL (50/50) 블렌드의 신장율이 상당히 증가하였으며 SEM 관찰 결과 이는 상용화제로 인해 옥수수전분 알갱이와 PCL 기질간의 계면 접착력이 증가하였기 때문으로 판단된다. 그러나 모듈러스와 인장강도는 상용화치 사용에도 불구하고 별다른 변화가 없었다.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.233-239
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• 2001

Local drug delivery by using biocompatible polymers has been developed in the treatment of periodontitis for many years. In the field of dental therapy, doxycycline is usually a first choice because of its broad-spectrum antibiotic activity. The strip releases antibiotics for a week, and the polymer should be degradable after a week. In this study, we prepared and evaluated the chitosan strips and nanoparticle strips containing doxycycline hydrochloride, and studied their antiacterial activity, dissoultion, and degrability in vitro. The weight of cast strip containing a 5 mg of doxycycline hydrochloride and a 45 mg of chitosan polymer was $57.67{\pm}0.17\;mg$. The release rate of doxycycline hydrochloride from the strip was measured by HPLC. The drug released from chitosan strip and nanoparticle strip was shown to be $50\;{\mu}g/mL$ in first 24 hours. In antibacterial test showed growth inhibitory activity after 24 hrs anaerobic incubation. In vitro degradability showed demolished weight of $93.74{\pm}0.08%$ chitosan strip, $82.48{\pm}1.29%$ chitosan nanoparticle strip, $2.47{\pm}1.99%$ polycarprolactione strip (control). These results showed that, with this doxycycline hydrochloride strip, it is feasible to obtain a sustained release of the drug within the periodontal pocket for seven days which may be improve for local drug delivery system for treatment of periodontal disease.

• 공업화학
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• 제7권3호
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• pp.481-489
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• 1996

이 연구에서는 촉매로서 tetraphenyltin을 사용하여 D,L-lactide (2-LA)와 ${\beta}$-methyl-${\delta}$-valerolactone(MVL)의 공중합체를 합성하고 그 물성을 조사하였다. 공중합체중의 lactic acid반복단위(LA)의 조성은 단량체 공급에서의 LA조성보다 높았다. 공중합체중의 그 조성은 공중합시간의 증가와 더불어 감소하였다. 그 공중합체의 수율과 분자량은 공급조성중의 LA의 증가와 더불어 증가하였다. 이들 결과는 공중합에 있어서 2-LA의 반응성이 MVL의 반응성보다 크다는 것을 뜻한다. 공중합체의 수평균분자량은 54,000에서 63,000의 범위에 있었고 다분산성지수는 1.7에서 2.1의 범위에 해당하였다. 공중합체는 융점을 나타내지 않았고 유리전이온도만 나타내었다. Lipase에 의한 공중합체의 분해성의 경향은 L-lactide-MVL 공중합체의 분해성의 경향과 거의 같았다.

• 공업화학
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• 제16권5호
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• pp.693-697
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• 2005

제지산업에서 COD 부하 및 난분해성 COD 부하가 높은 생산지종별 발생폐수의 처리방안을 통하여 단위공정의 최적화와 방류수의 수질 안정화에 대해 연구하였다. 그 결과 1차 처리 공정에서는 SS와 더불어 colloid성 물질제거를 통한 COD 제거효율을 향상시키기 위해서 음이온 응집제 및 Alum의 병행사용이 효과적인 것으로 분석되었다. 또한 Fenton 산화법의 병행사용으로 인한 약품의 과량투입은 수질상태에 악영향을 주는 것으로 확인되었기 때문에 최적량인 $FeCl_2$와 $H_2O_2$의 비가 1:1인 농도비 1000 ppm 일 때 COD 제거율이 가장 높다고 판단된다.

• 한국전기전자재료학회논문지
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• 제26권12호
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• pp.920-923
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• 2013

In this paper, the characteristics of a carbon nanotube composite heat sink proposed to replace the advanced Al heat sinks for LED lighting devices were studied. Proposed CMP-PLA heat sink was made by mixing 20~70 wt% carbon nanotube, 20~70 wt% bio-degradable polymer of melt-blended PLA (poly lactic acid) and PBS (poly butylene succinate) and PLA nucleating agents composed of the mixture of soybean oil and biotites, at $150{\sim}220^{\circ}C$ with 1,000~1,500 rpm. Optical and electric characteristics of 7.5 W LED lighting devices using heat sinks with such prepared CMP-PLA were investigated. And, the properties of the heat, which was not released from the CMP-PLA type heat sinks, was also investigated. The color temperature of LED lighting devices using the CMP-PLA heat sinks was 5,956 K, which is x= 0.32 and y= 0.34 in the XY chromaticity, and the color rendering index was 75. The luminous flux and the luminous efficiency of LED lighting devices using the CMP-PLA heat sinks was 540.6 lm and 72.68 lm/W respectively. Measured initial temperature of the heat sinks was $27^{\circ}C$, and their temperature increased as time to be saturated at $52^{\circ}C$ after an hour.

• Journal of Periodontal and Implant Science
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• 제43권6호
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• pp.251-261
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• 2013

A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.