• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.108-115
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• 2018

In bone tissue engineering, polycaprolactone (PCL) is one of the most widely used biomaterials to manufacture scaffolds as a synthetic polymer with biodegradability and biocompatibility. The polymer deposition system (PDS) with four axis heads, which can dispense bio-polymers, has been used in scaffold fabrication for tissue engineering applications. A dual-head deposition technology of PDS is an effective technique to fabricate 3D scaffolds. The electrospinning technology has been widely used to fabricate porous and highly interconnected polymer fibers. Thus, PDS can fabricate nanofiber-combined hybrid scaffolds using fused deposition modeling (FDM) and electrospinning methods. This study aims to fabricate nanofiber-combined scaffolds with uniform nanofibers using PDS. The PCL nanofibers were fabricated and evaluated according to the fabrication process parameters. PCL nanofibers were successfully fabricated when the applied voltage, tip-to-collector distance, flow rate, and solution concentration were 5 kV, 1 cm, 0.1 ml/h, and 8 wt%, respectively. The cell proliferation was evaluated according to the electrospinning time. Scanning electron microscopy was used to acquire images of the cross-sectioned hybrid scaffolds. The cell proliferation test of the PCL and nanofiber-combined hybrid scaffolds was performed using a CCK-8 assay according to the electrospinning time. The result of in-vitro cell proliferation using osteosarcoma MG-63 cells shows that the hybrid scaffold has good potential for bone regeneration.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.115-124
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• 2007

Silica is known as a promising osteoconductive material, and polycaprolactone is a bioactive and degradable material. The purpose of this study was to monitor the differentiation of MC3T3-E1 cells cultured on the layer-built silica/poly caprolactone non-woven fabric produced by electrospinning. Non-woven fabric (silica, polycaprolactone, PSP, SPS) was made by electrospinning and they were inserted in the 48 well cell culture plate. MC3T3-E1 cells were prepared by subculture. Cells were seeded to each well $1{\times}10^5$ concentration per well. Dulbecco's modified eagle medium with 10% FBS and 1% antibiotic-antimycotic solution was used. Confocal laser scanning microscope was taken 4 hours after incubation (95% air. 5% $CO_2$, $37^{\circ}C$). Cell proliferation was monitored by spectrophotometer on 1, 7, 14 days, and the morphology of the growing cells was observed by field emission scanning electron microscope. To monitor the differentiation of osteoblasts on the materials, MC3T3-E1 cells were incubated in 48 well culture plate after seeding with the density of $1{\times}10^5$ concentration. Then ELISA kit & EIA kit were used on to assess osteocalcin and osteopontin expression respectively. The other conditions were the same as above. MC3T3-E1 cells were proliferated well on all of the materials. There were no statistical differences among them. The osteopontin expression of silica, PSP, SPS was significantly higher than other groups on day 3 (p/0,05), but after that time, there were no statistically signigicant differences. The osteocalcin expression was significantly higher in silica and PSP than other groups on day 14. These findings show that PSP was as good as silica on the effect of osteoblast differentiation. The PSP non-woven fabric may have the possibility as bone graft materials.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.342-347
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• 2011

The effects of compatibilizers on the mechanical and rheological properties of PP/PCL and TPO/PCL blends have been studied. The thermoplastic polyolefin (TPO) consists of PP (80 wt%), EPDM (15 wt%) and Talc (5 wt%). Maleic anhydride grafted polypropylene (PP-g-MAH) and maleic anhydride grafted styrene-(ethylene-co-butene)-styrene copolymer (SEBS-g-MAH) were used as compatibilizers. In mechanical properties of PP/PCL and TPO/PCL blends, tensile strength was increased when PP-g-MAH was used as a compatibilizer, and impact strength was increased when SEBS-g-MAH was used as a compatibilizer. From the results of SEM morphology of PP/PCL blend, PCL droplet size was decreased by the addition of PP-g-MAH. From the results of rheological property, complex viscosity of the PP/PCL and TPO/PCL blends did not change appreciably when the compatibilizers were added. From the results of mechanical, morphological and rheological properties of the blends, PP-g-MAH acted as a compatibilizer to increase the tensile strength of the PP/PCL and TPO/PCL blends. While SEBS-g-MAH acted as a impact modifier to increase the impact strength of the PP/PCL and TPO/PCL blends.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.371-377
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• 2014

In tissue engineering, a scaffold is a three-dimensional(3D) structure that serves as a template for regeneration the functions of damaged tissues or organs. Among materials for scaffolds, polycaprolactone(PCL) and ${\beta}$-tricalcium phosphate(${\beta}$-TCP) are biodegradable and biocompatible. In this study, we fabricated 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %), and pure ${\beta}$-TCP scaffolds by a multi-head scaffold fabrication system. Scaffolds with a pore size of $600{\pm}20{\mu}m$ was observed by scanning electron microscopy. The effects of 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) and pure ${\beta}$-TCP scaffolds were analyzed by evaluating their mechanical characteristics. In addition, in an in-vitro study using osteoblast-like saos-2 cells, we confirmed the effects of 3D scaffolds on cellular behaviors such as cell adhesion and proliferation. In summary, the 3D blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) scaffold was found to be suitable for human cancellous bone in terms of its the compressive strength, biocompatibility, and osteoconductivity. Thus, blending PCL and ${\beta}$-TCP could be a promising approach for fabricating 3D scaffolds for effective bone regeneration.

• Polymer(Korea)
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• v.38 no.6
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• pp.815-819
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• 2014

Scaffolds of tissue engineering should be biocompatible and biodegradable for cell attachment, proliferation and differentiation. In the various scaffold fabrication, 3D printing technique can make the three dimensional scaffold with interconnected pores for cell ingrowth. Polycaprolactone (PCL) is biodegradable polyester with a low melting temperature and has been approved by the Food and Drug Administration (FDA). In this study, PCL scaffold was fabricated by 3D bioprinting system and surface modification of PCL scaffold was controlled by NaOH treatment. Morphological change and wetability of NaOH-treated scaffold were observed by SEM and contact angle measurement system. The remnant of PCL treated with NaOH was measured by ATR-FTIR. In vitro study of scaffolds was evaluated with WST-1 and ALP activity assay. NaOH treatment of PCL scaffolds increased surface roughness, hydrophilicity, cell proliferation and osteogenic differentiation. These results indicate that NaOH-treated PCL scaffold made by 3D bioprinting has tissue engineered potential for the development of biocompatible material.

• Polymer(Korea)
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• v.38 no.1
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• pp.93-97
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• 2014

Biodegradable drug-eluting stent has dual functions of supporting the lumen and treating internal tumor preventing the restenosis by releasing drug. In this study, the polycaprolactone (PCL) based three dimensional (3D) mesh loaded with paclitaxel (PTX) was presented by rapid prototyping (RP) technique of solid freeform fabrication (SFF) for biodegradable drug-eluting stent application. PCL has many advantageous properties such as good biocompatibility, good mechanical properties, and good drug permeability. PTX is widely used in the cancer treatment by inhibiting tumor cell proliferation. Analytical methods of HPLC and NMR were used for simultaneous quantification of PTX. Scanning electron microscopy (SEM) was performed to observe the architecture and morphologies of 3D mesh. The cytotoxicity assay results indicated released PTX's biological activity. This study provided that PCL based 3D mesh loaded with PTX by RP technique has great potential for biodegradable drug-eluting stent application.