• IMMUNE NETWORK
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• 제13권1호
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• pp.30-33
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• 2013

Previously we showed that biodegradable nanoparticles containing poly-IC or CpG oligodeoxynucleotide (ODN) together with ovalbumin (OVA) were efficient at inducing MHC-restricted presentation of OVA peptides in dendritic cells. The CTL-inducing activities of the nanoparticles were examined in the present study. Nanoparticles containing poly-IC or CpG ODN together with OVA were prepared using biodegradable polymer poly(D,L-lactic acid-co-glycolic acid), and then were opsonized with mouse IgG. The nanoparticles were injected into the tail vein of mice, and 7 days later the OVA-specific CTL activities were measured using an in vivo CTL assay. Immunization of mice with the nanoparticles containing poly-IC or CpG ODN together with OVA elicited potent OVA-specific CTL activity compared to those containing OVA only. In accordance with these results, nanoparticles containing poly-IC or CpG ODN together with OVA exerted potent antitumor activity in mice that were subcutaneously implanted with EG7.OVA tumor cells. These results show that encapsulation of poly-IC or CpG ODN together with antigen in biodegradable nanoparticles is an effective approach for the induction of potent antigen-specific CTL responses in vivo.

• 대한치과보철학회지
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• 제48권2호
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• pp.158-165
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• 2010

연구목적: 본 연구는 hyaluronic acid (HA)를 poly (D, L-lactic-co-glycolic acid) (PLGA)에 적용하여 새로 개발된 차폐막들을 실험군으로, 차폐막이 사용되지 않은 조건과 시중에 사용 중인 collagen membrane ($Ossix^{TM}$)을 이용한 조건을 대조군으로 하여, 토끼 두개골에 형성된 골 결손부에 4, 8, 12주간 적용하고 조직학적인 관찰을 함으로써 골 재생 능력을 비교 평가하고자 한다. 연구 재료 및 방법: 12마리의 웅성 가토 두개골에, 6 mm 직경의 골 결손부를 4개씩 형성하였다. 각각의 결손부는 5가지 중 하나의 차폐막으로 덮여졌다; No-membrane, Collagen, PLGA, HA-coated-PLGA, HA-PLGA/PLGA. 4주, 8주, 그리고 12주 후 두개골을 절단하여H-E 염색한 후 조직학적 분석을 하였다. 결과: 본 연구에서, 차폐막을 사용하지 않은 군에서 골형성은 12주 후에 나타났으며, 골 결손부를 일부 채우고 있었다. 신생골은 하방의 뇌경막을 따라 형성되었고 결손부의 상부는 결합조직과 지방으로 채워져 있었다. 콜라겐 차폐막인 $Ossix^{TM}$는 4주 후부터 신생골을 보였으며 신생골은 차폐막을 따라 형성되어 있었고 12주 까지 차폐막이 유지되었다. PLGA, HA-coated-PLGA, HA-PLGA/PLGA는 4주 후부터 골 재생을 보이고 8주 후에 결손부를 전반적으로 채우고 있다. 12주에는 기존 골과 구분이 되지 않으며 잘 융합되어 있음을 알 수 있다. 차폐막은 4주 후부터 명확히 구분되지 않고 흡수되어 있었다. 결론:PLGA와 HA-coated-PLGA, HA-PLGA/PLGA는 대조군에 비해 골의 형성이 빠르고 성숙 또한 빠르게 나타났으나, HA의 적용에 따른 차이를 보이지 않았으며 4주 후부터 흡수되어 차폐막으로써 임상에서 사용하기 위해서는 흡수기간을 연장하여 조절 가능하도록 더 많은 연구가 필요할 것으로 생각된다.

• Macromolecular Research
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• 제14권5호
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• pp.510-516
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• 2006

Lactide was produced from oligomeric PLA by back-biting reaction of the OH end groups. For optimization of the reaction conditions, the effects of temperature, pressure, PLA molecular weight, and catalyst type on the lactide synthesis were examined. The fraction of D,L-lactide decreased with increasing temperature. Among the various Sn-based catalysts, the D,L-lactide fraction was maximized when SnO was used. A higher yield with lower racemization was observed at lower pressure. The conversion of PLA was maximized at an oligomeric PLA molecular weight of ca. 1380. The yield of lactide increased but the fraction of D,L-lactide decreased with increasing molecular weight. The highest conversion with the lowest racemization degree was obtained at a catalyst concentration of 0.1 wt%. The lactide was more sensitive to racemization because of the entropic effect.

• 생명과학회지
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• 제31권9호
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• pp.849-855
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• 2021

최근에는 나노기술이 다양한 분야에 도입되고 활용되면서 신약개발이 가속화되고 있다. 나노입자는 약물의 단일 투여로 장기간 동안 혈중 약물 농도를 유지하고, 병리학적 부위에만 선택적으로 방출되는 장점이 있어 비병리 주위에 대한 부작용을 줄일 수 있다. Poly (D,L-lactic-co-glycolic acid) (PLGA)는 가장 광범위하게 개발된 생분해성 고분자 중 하나이다. PLGA는 다양한 응용분야의 약물전달에 널리 사용된다. 또한 FAD에 의해 약물전달 시스템으로 승인되었으며, 유전자 치료제와 같은 제어방출제형에 널리 적용된다. PLGA 나노입자는 수동 및 능동 표적화 방법을 사용하여 특정 세포 유형에 고효율의 전달 시스템으로 개발되었다. 이러한 PLGA 나노입자를 이용한 약물전달체 개발 후 표적 부위에 선택적으로 약물을 전달하고 질병에 따라 장기간 유효 혈중 농도를 최적화한다. 이 리뷰논문에서 우리는 유전자 치료를 위한 PLGA 나노 물질을 기반으로 하는 성상 세포 선택적 나노입자의 개발을 조사하여 세포 특이적으로 치료결과를 향상시키는 방법에 중점을 두고자 한다.

• Journal of Pharmaceutical Investigation
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• 제39권3호
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• pp.167-171
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• 2009

Poly(lactic-co-glycolic acid) (PLGA) microspheres have been a useful tool as a controlled drug delivery system for peptides and proteins. Recently, porous microspheres have gained great attention as inhalation drug delivery system due to their low aerodynamic densities. Here, we report highly porous PLGA microspheres, which were prepared by using a single o/w emulsification/solvent evaporation method. Two types of porogen, i.e., (i) extractable Pluronic F127 and (ii) gas foaming salt of ammonium bicarbonate, were used to induce pores on the surface of PLGA microspheres. The respective preparation conditions on dp/cp ratio and porogen concentration were determined by the previous preliminary experiments, and other preparation factors were further optimized on the basis of PLGA Mw and porogen type. The morphological features examined by scanning electron microscope (SEM) show these porous microspheres have highly porous surface structure with a diameter range of 20${\sim}$30 ${\mu}$m. These highly porous PLGA microspheres, which have much lower density, would be a practical aerosol system for pulmonary drug delivery.

• Archives of Plastic Surgery
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• 제34권2호
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• pp.141-148
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• 2007

Purpose: The object of this study was to evaluate the development of continuous osteogenic differentiation and bone formation after the subcutaneous implantation of the tissue-engineered bone, in vitro. Methods: Human adipose-derived stem cells were obtained by proteolytic digestion of liposuction aspirates. Adipose-derived stem cells were seeded in PLGA scaffolds after being labeled with PKH26 and cultured in osteogenic differentiation media for 1 month. The PLGA scaffolds with osteogenic stimulated adipose-derived stem cells were implanted in subcutaneous layer of four nude mice. Osteogenesis was assessed by RT-PCR for mRNA of osteopontin and bone sialoprotein(BSP), and immunohistochemistry for osteocalcin, and von Kossa staining for calcification of extracellular matrix at 1 and 2 months. Results: Implanted PLGA scaffold with adipose-derived stem cells were well vascularized, and PLGA scaffolds degraded and were substituted by host tissues. The mRNA of osteopontin and BSP was detected by RT-PCR in both osteogenic stimulation group and also osteocalcin was detected by immunohistochemistry at osteogenic stimulation 1 and 2 months, but no calcified extracellular deposit in von Kossa stain was found in all groups. Conclusion: In vivo, it could also maintain the characteristics of osteogenic differentiation that adipose-derived stem cells within PLGA scaffold after stimulation of osteogenic differentiation in vitro, but there were not normal bone formation in subcutaneous area. Another important factor to consider is in vivo, heterologous environment would have negative effect on bone formation as.[p1]

• Journal of Biosystems Engineering
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• 제32권1호
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• pp.50-56
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• 2007

Highly porous composite bioceramic bone scaffolds were developed using sintered gnotobiotic pig bones. These scaffolds consisted of poly-D,L-lactic acid (P(D,L)LA) and bioceramic materials of pig bone powder. The bone scaffolds were able to promote biocompatibility and possess interconnected pores that would support cell adhesion and proliferation adequately. The composite scaffolds were tested with dental pulp stem cells for cytotoxicity test. Cells seeded on the composite scaffolds were readily attached, well proliferated, as confirmed by cytotoxicity test, and cell adhesion assessment. The composite bone scaffold had no toxicity in cytotoxicity test on the extract of 0.013 g scaffold to 2 ml culture medium. The cells on the composite bone scaffold proliferated better than cells on the P(D,L)LA scaffolds.

• 한국발생생물학회지:발생과생식
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• 제15권2호
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• pp.87-98
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• 2011

본 실험은 bioceramic을 첨가하여 만든 다공성 poly D,L-lactic-co-glycolic acid(PLGA)-scaffold가 인간 지방조직에서 유래된 중간엽 줄기세포(human adipose tissue derived mesenchymal stem cells, ATMSCs)의 골 형성과정에 효과적인지를 알아보고자 수행하였다. ATMSCs를 well plate에 접종하여 골형성 유도(osteogenic induction, OI) 배양액으로 28일 동안 배양하였다. OI배양액군의 증식률은 세포접종 후 14일까지는 세포증식이 활발하게 진행됐지만, 21일 이후 세포의증식이 둔화되는 양상을 보였다. 반면, 기본배양액군은 꾸준한 세포 증식을 보이며 21일 이후에는 OI배양액군보다 더 높은 증식을 나타냈다. OI배양액군의 alkaline phosphatase(ALP) 활성은 세포배양 21일까지는 증가했지만, 28일에는 감소한 반면에 기본배양액군은 계속 감소하는 양상을 띠었다. OI배양액군의 세포는 배양 21일에는 뚜렷한nodule의 형성을 관찰할 수 있었고, nodule에 칼슘의 축적이 일어남을 확인하였다. ATMSCs를 scaffold에 접종하여 OI배양액으로 배양하였다. Scaffold 내 골아세포 분화에 따른 ALP 활성은 PLGA scaffold와 Bioceramic-PLGA scaffold 모두에서 세포 배양 21일에 급격히 증가하였고, Bioceramic-PLGA scaffold의 ALP 활성이 PLGA scaffold보다 크게 증가하였다. 칼슘과 인의 함량 역시 Bioceramic-PLGA scaffold에서 높게 나타났으며, Bioceramic-PLGA scaffold의 Ca/P ratio가 PLGA scaffold보다 높게 나타났다. 생체내에 이식된 scaffold의 생분해성과 광물화는 bioceramic-PLGA scaffold에서 더욱 뚜렷하게 관찰되었다. 본 실험의 결과들을 종합해 볼 때 ATMSCs의 골형성능은 well plate보다 scaffold가 더 효과적이며, bioceramic이 scaffold의 세포 부착률과 ALP 활성을 증가시켜 골형성능에 효과적으로 작용하는 것으로 생각된다. 또한 bioceramic이 ATMSCs의 골형성 분화에 따른 광물화단계의 scaffold 내 칼슘과 인의 함량을 증가시키는 것으로 사료된다.생체 내 scaffold의 생분해성은 PLGA scaffold보다 Bioceramic-PLGA scaffold가 빠른 분해를 나타내며, 광물화에 따른 칼슘 침착이 더 활발한 것은 scaffold에 포함된 bioceramic이 생체 내 세포의 부착, 증식, 분화를 증가시켜 골형성을 촉진시키는 물질로 작용한 것으로 사료된다.

• Journal of Pharmaceutical Investigation
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• 제40권4호
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• pp.245-250
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• 2010

Porous poly(lactic-co-glycolic acid) microspheres (PLGA MS) have been utilized as an inhalation delivery system and a matrix scaffold system for tissue engineering. Here, gelatin (type A) is introduced as an extractable pH-responsive porogen, which is capable of controlling the porosity and pore size of PLGA microspheres. Porous PLGA microspheres were prepared by a water-in-oil-in-water ($w_1/o/w_2$) double emulsification/solvent evaporation method. The surface morphology of these microspheres was examined by varying pH (2.0~11.0) of water phases, using scanning electron microscopy (SEM). Also, their porosity and pore size were monitored by altering acidification time (1~5 h) using a phosphoric acid solution. Results showed that the pore-forming capability of gelatin was optimized at pH 5.0, and that the surface pore-formation was not significantly observed at pHs of < 4.0 or > 8.0. This was attributable to the balance between gel-formation by electrostatic repulsion and dissolution of gelatin. The appropriate time-selection between PLGA hardening and gelatin-washing out was considered as a second significant factor to control the porosity. Delaying the acidification time to ~5 h after emulsification was clearly effective to make pores in the microspheres. This finding suggests that the porosity and pore size of porous microspheres using gelatin can be significantly controlled depending on water phase pH and gelatin-removal time. The results obtained in this study would provide valuable pharmaceutical information to prepare porous PLGA MS, which is required to control the porosity.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1490-1495
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• 2009

The development of nanotechnology has penetrated the fields of biology and medicine, resulting in remarkable applications for tissue regeneration. In order to apply this technology to tissue engineering, we have developed nano-scaled 3D scaffolds consisting of growth factor-loaded heparin/poly(l-lysine) nanoparticles (NPs) attached to the surface of polymeric micro spheres via polyionic complex methods. Growth factor-loaded NPs were simply produced as polyelectrolyte complexes with diameters of 100-200 nm. They were then coated onto positively charged poly(lactic-co-glycolic acid) (PLGA) pretreated with polyethyleneimine to enable cell adhesion, proliferation, and stimulation of neurite outgrowth. Propidium iodide staining and $\beta$-tubulin analysis revealed that neuronal PC12 cells proliferated extensively, expressed significant amounts of b-tubulin, and showed well-structured neurite outgrowth on polymeric microspheres by stimulation with growth factors. These results suggest that cellular adhesion and biological functionality on prepared PLGA microspheres enabled terminal differentiation of neuronal cells.