• 방사선산업학회지
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• 제12권4호
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• pp.343-348
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• 2018

Preliminary study was perfomed to develop a biocompatible filter material using radiation energy. Electrosppined PLLA nano sheets were surface-modificated with hydrophilic groups(acrylic group) by using radiation. The physico-chemical and morphological characteristics of modified PLLA sheets were measured by ATR, SEM, contact angle, and hydrophilic (acryl group) introduction rate (TBO). As a result, there was no morphological(fiber structure) structure change due to radiation, and it was confirmed that an acrylic group was successfully introduced onto PLLA fiber sheet by radiation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권6호
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• pp.635-639
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• 2008

Objectives : the effect of different sterilization methods on the surface morphology of PPDO-hybrid-PLGA nanofiber scaffold and attachments of PC12 cell were investigated. Methods : Poly (p-dioxone)-hybrid-Poly (lactide-glycolide) (PPDO-hybrid-PLGA) nanofiber scaffold, fabricated in a tube form with 1.5 mm internal diameter, 0.2 mm thickness and 5 mm length, was prepared using electrospinning method. To study the surface morphology using SEM, The study group and control group in respective were; Control:Non-sterilized scaffold, Group I:scaffold sterilized with 70% Alcohol, Group II: scaffold sterilized with Ethylene Oxide at $65^{\circ}C$, and Group III: scaffold sterilized with Ethylene Oxide at $37^{\circ}C$. To investigate viability of the PC12 cell on the scaffold, The study group and control group in respective were; Control: sterilized with 70% Alcohol, Group I: sterilized with Ethylene Oxide at $65^{\circ}C$, and Group II: sterilized with Ethylene Oxide at $37^{\circ}C$. Results : 1. The surface morphology was slightly changed in Group I, II and Group III, compared with control. 2. The attachment of PC12 cells in Group I, II was not higher than in control Discussion : The attachment of PC12 cell is not influenced by different sterilization methods.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.559-564
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• 2006

According to the development of operation technique and biologic materials, oromaxillofacial surgery department have used many kinds of metal and biologic materials in ORIF and plastic surgery. In maxillofacial fracture, ORIF with metal plate and screw have short healing period and good prognosis. But ORIF with metal materials have many complications as maxillofacial abnormal growth, screw loosening, bone malunion. And metal materials have not used in infection site. The purpose of this study is to evaluate the clinical value of 10 condylar fracture patients operated with absorbable screw at Wonkwang university. Ten patients(8 males, 2 female, mean aged 28) who had mandibular condyle process fracture treated with PLLA implants(poly-l-lactide) was recalled for follow-up clinical and radiologic examination for 10 years. Mouth opening recorvered to more than 35mm and occlusion was stable in all patients. All fractured mandibular condyles showed anatomic good reduction and long-term stability with the use of resorbable miniplates and screw. Bone healing was satisfactory in all patients, and there was no evidence of abnormal resorption of condylar process.

• 대한의용생체공학회:의공학회지
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• 제9권2호
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• pp.225-232
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• 1988

Poly (L- lactic acid-co-glycine-L-lactic acid) and Poly (L-lactic acid-co-glycine-L- methyl lactic acid ) have been prepared by ring opening polymerization. The monomer 6, 6-dimethyl morpho-line-2, 5-dione was synthesized by the bromoisobutylation of 2-bromoisobutyryl bromide with glycin e. L-lactide, 6-methyl morpholine-2, 5-diode. and 6, 6-dimethyl morpholine-2, 5-diode have been used as starting materials for polydepsipeptides. The synthesized monomers and copolymers have been identified by NMR and FT-lR spa- ctrophotometer. The thermal propert ies and glass transition temperature(Tg) of the copolymers have been measured by differential scanning calorimetry. The Tg values of poly(L-lactic acid co-glycine-L-lactic acid) system are increased from $53^{\circ}C\; to\; 107^{\circ}C$ with increasing the mole fraction of 6-methyl morpholine-2, 5-diode. And the Tg values of poly(L-lactic acid co-glycine-L-methyl lactic acid) system are increased from $53^{\circ}C\;to\;138^{\circ}C$ with increasing the mole fraction of 6. 6-dimethyl morpholine-2, 5-diode The thermal stability of poly (L-lactic acid-co-glycine-L-methyl lactic acid) is slightly greta text than that of poly(L-lactic acid-co-glycine-L-lactic acid) due to the methyl group.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4915-4918
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• 2014

Background and Aims: Advances in the treatment of cervical cancer over the last decade have predominantly involved the development of genes directed at molecular targets. Gene therapy is recognized to be a novel method for the treatment of cervical cancer. Genes can be administered into target cells via nanocarriers. This study aimed to develop systemically administrable nano-vectors. Floate (Fa) containing gene loaded nanoparticles (NPs) could target HeLa human cervical cancer cells through combination with receptors on the cells to increase the nuclear uptake of genetic materials. Methods: Fa was linked onto Poly (ethylene glycol)-b-poly (D, L-lactide) (PEG-PLA) to form Fa-PEG-PLA, and the resulting material was used to load plasmids of enhanced green fluorescence protein (pEGFP) to obtain gene loaded nanoparticles (Fa-NPs/DNA). Physical-chemical characteristics, in vitro release and cytotoxicity of Fa-NPs/DNA were evaluated. The in vitro transfection efficiency of Fa-NPs/DNA was evaluated in HeLa cells and human umbilical vein endothelial cells (HUVEC). PEG-PLA without Fa was used to load pEGFP from NPs/DNA as a control. Results: Fa-NPs/DNA has a particle size of 183 nm and a gene loading quantity of 92%. After 72h of transfection, Fa-NPs/DNA displayed over 20% higher transfection efficiency than NPs/DNA and 40% higher than naked DNA in HeLa cells. However, in HUVECs, no significant difference appeared between Fa-NPs/DNA and NPs/DNA. Conclusions: Fa-PEG-PLA NPs could function as excellent materials for gene loading. This nano-approach could be used as tumor cell targeted medicine for the treatment of cervical cancer.

• Journal of Pharmaceutical Investigation
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• 제36권2호
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• pp.109-114
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• 2006

Biodegradable poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles were developed for sustained delivery of water-soluble macromolecules. PLGA nanoparticles were fabricated by spontaneous emulsification solvent diffusion method generating negatively charged particles and heterogeneous size distribution. As a model drug, blue dextran was encapsulated in PLGA nanoparticles. In addition, nanoparticles were also prepared with varying ratio of poloxamer 188 (P188) and poloxamer 407 (P407), and coating with poly(vinyl alcohol) (PVA). Then, the particle size, zeta potential and encapsulation efficiency of nanoparticles containing blue dextran were studied. In vitro release of blue dextran from nanoparticles was also investigated. The surface and morphology of nanoparticles were characterized by scanning electron microscopy (SEM). In case of nanoparticles prepared with PLGA, P407, and different organic solvents, particle size was in the range of $230{\sim}320\;nm$ and zeta potentials of nanoparticles were negative. The SEM images showed that ethyl acetate is suitable for the formulation of PLGA nanoparticles with good appearance. Moreover, ethyl acetate showed higher encapsulation efficiency than other solvents. The addition of P188 to formulation did not affect the particle size of PLGA nanoparticles but altered the release patterns of blue dextran from nanoparticles. However, PVA, as a coating material, altered the particle size with increasing the PVA concentration. The nanoparticles were physically stable in the change of particle size during long-term storage. From the results, the PLGA nanoparticles prepared with various contents of poloxamers and PVA, could modulate the particles size of nanoparticles, in vitro release pattern, and encapsulation of water-soluble macromolecules.

• 폴리머
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• 제25권6호
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• pp.893-901
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• 2001

조직공학적 신경재생 및 파킨슨씨병 등의 시경퇴행성 질환에서의 치료에 이용 목적으로 신경성장인자(nerve growth factor, NGF)를 생분해성 고분자 담체에 NGF를 서방화시키고자 PLA 담체에 함유시켜 유화동결건조법으로 제조하였다. 제조된 NGF의 방출량은 생체외 pH 7.4, 37$^{\circ}C$의 PBS 조건하에서 4주 동안 방출실험 하였으며, 함유된 NGF의 활성을 확인하기 위하여 PC-l2 세포에 직접 배양하여 확인하였다. 제조되어진 PLA 담체는 열린 셀 구조를 가졌으며, 초기 NGF의 함량이 많을수록 방출량도 증가를 보였으며, 제조과정에서의 NGF의 환성을 확인하기 위하여 PC-12 세포를 배양한 결과 신경돌기가 성장하였다. 본 연구는 생분해성 고분자 특정인 확산과 분해에 의해서 생물학적 활성물질인 NGF의 방출을 조절할 수 있으며, 조직공학적으로 서방화되어 3차원적인 신경재생을 가능케 할 것으로 기대된다.

• 폴리머
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• 제33권5호
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• pp.458-462
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• 2009

본 연구에서는 순차적 음이온 및 개환중합반응을 통해 ABC 형태의 폴리스티렌-폴리에틸렌옥사이드-폴리락티드 블록공중합체를 성공적으로 합성하였다. 우선, 첫번째 블록인 폴리스티렌을 합성하기 위해서, 사이클로헥산 용매에서 스티렌/이차-부틸리튬을 각각 단량체/개시제로 사용하여 음이온중합(anionic polymerization)을 수행하였고, 이후 고분자 말단을 수산기로 전환시키기 위해, 에틸렌옥사이드를 첨가하였다. 다음 단계로 포타슘 나프탈레나이드(potassium naphthalenide)를 이용하여 폴리스티렌 말단 수산기의 수소를 제거하여, 거대개시제인 PS-$O^-K^+$를 제조하였다. 준비된 거대 개시제에 정량된 에틸렌옥사이드를 첨가하여, 음이온중합을 수행하였다. 폴리락티드 블록을 도입시키는 개환중합의 경우, THF 용매에서 트리에틸알루미늄(triethylaluminum)/피리딘(pyridine)시스템을 이용하여 PS-b-PEO-$AlEt_2$ 형태의 거대개시제를 형성한 후, $90^{\circ}C$에서 중합을 수행하였다. 합성된 블록공중합체를 수소핵자기공명법 및 겔침투크로마토그래피 방법을 통해 조사한 결과, 잘 정의된 분자량 및 낮은 분자량 분포를 나타냄을 확인할 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3753-3758
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• 2015

Background: Polymeric nanoparticles are attractive materials that have been widely used in medicine for drug delivery, with therapeutic applications. In our study, polymeric nanoparticles and the anticancer drug, chrysin, were encapsulated into poly (D, L-lactic-co-glycolic acid) poly (ethylene glycol) (PLGA-PEG) nanoparticles for local treatment. Materials and Methods: PLGA: PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide as an initiator. The bulk properties of these copolymers were characterized using 1H nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. In addition, the resulting particles were characterized by scanning electron microscopy. Results: The chrysin encapsulation efficiency achieved for polymeric nanoparticles was 70% control of release kinetics. The cytotoxicity of different concentration of pure chrysin and chrysin loaded in PLGA-PEG ($5-640{\mu}M$) on T47-D breast cancer cell line was analyzed by MTT-assay. Conclusions: There is potential for use of these nanoparticles for biomedical applications. Future work should include in vivo investigation of the targeting capability and effectiveness of these nanoparticles in the treatment of breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6363-6368
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• 2012

Objective: The study aim was to prepare poly-DL-lactide-poly (PELA) microspheres encapsulating recombinant tissue inhibitors of metalloproteinase-1 (TIMP-1) in an adenovirus to investigate its inhibition on the proliferation of hepatocellular carcinoma cells HepG2. Methods: Microspheres were prepared by encapsulating the recombinant TIMP-1 adenovirus into biodegradable PELA. The particle size, viral load, encapsulation efficiency and in-vitro release were measured. Microspheres were used to infect HepG2 cells, then infection efficiency was examined under a fluorescent microscope and ultrastructural changes assessed by TEM. Expression of TIMP-1 mRNA in HepG2 cells was examined by semi-quantitative RT-PCR and proliferation by MTT and cell growth curve assays. Results: We successfully prepared microspheres encapsulating recombinant TIMP-1 adenovirus with a diameter of $1.965{\mu}m$, an encapsulation efficiency of 60.0%, a viral load of $10.5{\times}10^8/mg$ and approximate 60% of virus release within 120 h, the total releasing time of which was longer than 240 h. The microspheres were confirmed to be non-toxic with blank microspheres. Infected HepG2 cells could stably maintain in-vitro expression of TIMP-1, with significantly effects on biological behaviour Conclusion: PELA microspheres encapsulating a recombinant TIMP-1 adenovirus can markedly inhibit the proliferation of HepG2 cells, which provides an experimental basis for polymer/chemistry-based gene therapy of hepatocellular carcinomas.