• 폴리머
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• 제34권3호
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• pp.185-190
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• 2010

전기방사공정에 의해 고분자의 나노 크기의 섬유를 만드는 기술로 널리 사용되어졌으며, 제작된 나노섬유는 그 높은 표면적과 형태학적 특성때문에 조직재생 공학분야에서 많이 사용되어져 왔다. 본 연구에서는 기존의 전기방사공정을 개선한 복합전기장을 이용하여 생분해성/생체적합성 poly(${\varepsilon}$-caprolactone) (PCL) 마이크로/나노섬유를 제작하였고, 기존의 나노섬유의 배열성보다 제어가 가능한 배열성을 갖는 공정시스템을 통하여 보다 우수한 배열성을 갖는 PCL 나노섬유를 제작하였다. 고배열된 PCL 나노섬유는 신경세포 재생을 위한 세포담체로서의 가능성을 확인하고자 신경세포(PC-12)를 배양하였으며 그 결과 높은 배열성을 갖은 PCL 나노섬유 매트에서 신경세포의 배열성이 얻어짐을 확인하였다.

• 방사선산업학회지
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• 제5권4호
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• pp.365-370
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• 2011

Electrospun nanofibers prepared with synthetic biodegradable polymer have some limitations in regulating adhesion, proliferation, and spreading of cells because of their surface hydrophobicity and absence of cell-interaction. In this study, we functionalized the electrospun poly(L-lactide-co-${\varepsilon}$-caprolactone) (PLCL) nanofibers with acrylic acid (AAc) to modulate their surface hydrophilicity using electron-beam irradiation method and then measured grafting ratio of AAc, water contact angle, and ATR-FTIR of AAc-grafted nanofibers. A grafting ratio of AAc on the nanofibers was increased as irradiation dose and AAc concentration were increased. AAc-grafted nanofibers also have higher wettability than non-modified nanofibers. In conclusion, those surface-modified nanofibers may be an essential candidate to regulate cell attachment in tissue engineering applications.

• 폴리머
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• 제36권2호
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• pp.124-130
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• 2012

본 연구의 목적은 전기방사법을 사용하여 poly(L-lactide-$co$-${\varepsilon}$-caprolactone) (PLCL)과 marine collagen (MC)이 혼합된 나노섬유를 제조하는 것이다. 전기방사된 나노섬유의 직경과 형태는 여러 공정 변수에 의해서 변화되는데, PLCL과 MC의 혼합비, 노즐과 콜렉터와의 거리, 노즐의 직경, 용액의 방출 속도 그리고 전기장의 세기 변화에 따라 나노파이버의 직경을 주사전자현미경을 통해서 분석하였다. 또한 제조된 나노파이버의 표면변화를 확인하기 위해 물과의 접촉각을 측정하였으며, 나노파이버의 세포 친화성을 평가하기 위해 MG-63을 이용하여 생존율과 흡착형태를 주사전자현미경과 형광현미경을 통해서 관찰하였다. 이와 같은 연구 결과, 방사거리, MC의 함량, 전기장의 세기가 증가할수록 제조된 나노파이버의 평균직경은 감소하는 경향을 나타냈다. 또한 MC의 함량이 증가할수록 나노파이버의 친수성이 증가하였고 세포독성은 관찰되지 않았다. 이에 따라 해양유래 생물에서 추출한 콜라겐은 조직공학용 소재에 새롭게 사용될 수 있을 것으로 예상된다.

• Tissue Engineering and Regenerative Medicine
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• 제15권6호
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• pp.735-750
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• 2018

BACKGROUND: The major challenge of tissue engineering is to develop constructions with suitable properties which would mimic the natural extracellular matrix to induce the proliferation and differentiation of cells. Poly(${\varepsilon}$-caprolactone)-poly(ethylene glycol)-poly(${\varepsilon}$-caprolactone) (PCL-PEG-PCL, PCEC), chitosan (CS), nano-silica ($n-SiO_2$) and nano-hydroxyapatite (n-HA) are biomaterials successfully applied for the preparation of 3D structures appropriate for tissue engineering. METHODS: We evaluated the effect of n-HA and $n-SiO_2$ incorporated PCEC-CS nanofibers on physical properties and osteogenic differentiation of human dental pulp stem cells (hDPSCs). Fourier transform infrared spectroscopy, field emission scanning electron microscope, transmission electron microscope, thermogravimetric analysis, contact angle and mechanical test were applied to evaluate the physicochemical properties of nanofibers. Cell adhesion and proliferation of hDPSCs and their osteoblastic differentiation on nanofibers were assessed using MTT assay, DAPI staining, alizarin red S staining, and QRT-PCR assay. RESULTS: All the samples demonstrated bead-less morphologies with an average diameter in the range of 190-260 nm. The mechanical test studies showed that scaffolds incorporated with n-HA had a higher tensile strength than ones incorporated with $n-SiO_2$. While the hydrophilicity of $n-SiO_2$ incorporated PCEC-CS nanofibers was higher than that of samples enriched with n-HA. Cell adhesion and proliferation studies showed that n-HA incorporated nanofibers were slightly superior to $n-SiO_2$ incorporated ones. Alizarin red S staining and QRT-PCR analysis confirmed the osteogenic differentiation of hDPSCs on PCEC-CS nanofibers incorporated with n-HA and $n-SiO_2$. CONCLUSION: Compared to other groups, PCEC-CS nanofibers incorporated with 15 wt% n-HA were able to support more cell adhesion and differentiation, thus are better candidates for bone tissue engineering applications.

• Macromolecular Research
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• 제16권2호
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• pp.139-148
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• 2008

Biodegradable and elastic poly(L-lactide-co-$\varepsilon$-caprolactone) (PLCL) was electrospun to prepare nanofibers, and N-isopropylacrylamide (NIPAAm) was then grafted onto their surfaces under aqueous conditions using $^{60}Co-{\gamma}$ irradiation. The graft yield increased with increasing irradiation dose from 5 to 10 kGy and the nanofibers showed a greater graft yield compared with the firms. SEM confirmed that the PLCL nanofibers maintained an interconnected pore structure after grafting with NIPAAm. However, overdoses of irradiation led to the excessive formation of homopolymer gels on the surface of thc PLCL nanofibers. The equilibrium swelling and deswelling ratio of the PNIPAAm-g-PLCL nanofibers (prepared with 10 kGy) was the highest among the samples, which was consistent with the graft yield results. The phase-separation characteristics of PNIPAAm in aqueous conditions conferred a unique temperature-responsive swelling behavior of PNIPAAm-g-PLCL nanofibers, showing the ability to absorb a large amount of water at < $32^{\circ}C$, and abrupt collapse when the temperature was increased to $40^{\circ}C$. In accordance with the temperature-dependent changes in swelling behavior, the release rate of indomethacin and FITC-BSA loaded in PNIPAAm-g-PLCL nanofibers by a diffusion-mediated process was regulated by the change in temperature. Both model drugs demonstrated greater release rate at $40^{\circ}C$ relative to that at $25^{\circ}C$. This approach of the temperature-controlled release of drugs from PNIPAAm-g-PLCL nanofibers using gamma-ray irradiation may be used to design drugs and protein delivery carriers in various biomedical applications.

• 폴리머
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• 제32권5호
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• pp.458-464
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• 2008

생체재생용 지지체는 높은 다공구조와 적당한 기계적인 강도를 필요로 한다. 높은 다중성과 적당한 다공크기는 지지체와 주변 환경 사이에 영양분의 공급을 원활하게 하여 셀의 지지체에 대한 초기 집착력과 성장을 가능하게 하는 구조를 제공한다. 본 논문에서는 polycaprolactone(PCL) 나노섬유를 화학 발포제와 전기방사공정을 이용하여 다양한 조건하에서 제조하였다. PCL 용액의 농도가 8wt%, 발포제의 함량 0.5wt%, 발포온도 $100^{\circ}C$ 및 체류시간 2-3초에서 가공성 측면과 다공성 측면에서 우수한 발포된 나노섬유를 얻을 수 있었다. 또한 세포의 성장성을 측정하기 위하여 인체피부세포를 셀 켤츄어링하여, 발포되지 않은 나노섬유와 비교하였다.

• 폴리머
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• 제39권2호
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• pp.323-328
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• 2015

졸-젤법을 이용한 전기방사법과 캐스팅법으로 폴리(${\varepsilon}$-카프로락톤)(PCL) 나노섬유와 PCL/실리카 막을 각각 제조하였다. 용매에 N,N-dimethylformamide(DMF)를 혼합한 경우 부드럽고 연속적인 PCL 나노섬유가 제조되었다. PCL 기지상에 tetraethyl orthosilicate(TEOS) 농도가 0에서 40 vol%로 증가함에 따라 PCL/silica의 강도는 12에서 8MPa로 감소하였지만, 7주까지 phosphate buffered saline solution(PBS) 침지에 따른 강도값의 변화는 없었다. 실리카 첨가에 따른 인장강도의 감소는 기공도의 증가에 기인하였다. PCL/실리카 막의 결정구조는 사방정계로 실리카 농도가 0에서 40 vol%로 증가함에 따라 crystallite 크기는 57에서 18 nm로 감소하였다. 세포독성 실험결과, PCL/실리카는 시편의 수축 및 변형이 없고, 검체 주위에서 변색이나 L-929 세포의 이상이 관찰되지 않는 무독성이었다.

• 방사선산업학회지
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• 제9권4호
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• pp.171-180
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• 2015

Vascular tissue engineering has been accessed to mimic the natural composition of the blood vessel containing intima, media, and adventitia layers. We fabricated mechanically expanded PLLA/PLCL nanofibers using electrospinning and UTM. The pore size of the meshes was increased the gelatin immobilized AAc-PLLA/PLCL nanofibers ($203.30{\pm}49.62microns$) than PLLA/PLCL nanofibers ($59.99{\pm}8.66microns$) after mechanical expansion. To increase the cell adhesion and proliferation, we introduced carboxyl group, and gelatin was conjugated on them. The properties of the PLLA/PLCL nanofibers were analyzed with SEM, ATR-FTIR, TBO staining, and water contact angle measurement, general cell responses on the PLLA/PLCL nanofibers such as adhesion, proliferation, and infiltration were also investigated using smooth muscle cell (SMC). During the SMC culture, the initial viability of the cells was significantly increased on the gelatin immobilized AAc-PLLA/PLCL nanofibers, and infiltration of the cells was also enhanced on them. Therefore, gelatin immobilized AAc-PLLA/PLCL nanofibers and mechanically expanded meshes may be a good tool for vascular tissue engineering application.

• 대한금속재료학회지
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• 제50권10호
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• pp.763-768
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• 2012

The uniform and highly smooth nanofibers of biocompatible poly(${\varepsilon}$-caprolactone) (PCL) composited with different contents of multiwalled carbon nanotubes (MWCNTs) were successfully prepared by electrospinning. Experimental parameters were MWCNTs addition to a PCL solution and applied voltages. The topographical features of the composite nanofibers were characterized by scanning electron microscopy and its electrical properties were measured by a four-point probe method. The surface resistance gradually decreased with an increasing content of MWCNTs in PCL fibers because of the excellent electrical conductivity of MWCNTs. The nanofiber diameter could be regulated by varying the solution viscosity and voltages. Our results establish that this kind of electrospinning PCL/MWCNTs nanofibers with the control of fiber diameter and electrical conductivity may be a promising candidate for the application of scaffolds in tissue engineering.