• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.177-181
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• 2021

Scaffolds protect the sensor in the body. Scaffolds are made of a bioabsorbable polymer. The polymer process is sensitive to humidity. Inside of the 3D printer has been improved to control the humidity. Specimens were produced by injection molding and 3D printer. 3D printed specimens were printed under various humidity conditions. We measured tensile strength of the injection-molded specimen and tensile strength of the 3d printing specimen. We compared tensile strength of the injection-molded specimen and tensile strength of the 3d printing specimen. Tensile strength of the injection-molded specimen is 557 kgf/cm². We confirmed tensile strength of the specimen was highest at 741 kgf/cm² when the humidity was 10 %. We confirmed lower the humidity, higher tensile strength of the polymer product.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권1호
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• pp.21-26
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• 2013

본 논문에서는 최근 미래 신산업 혁명을 주도할 유망기술로 각광 받고 있는 3D 프린팅 기술과 이를 이용한 조직공학 및 재생의학 분야의 응용 기술을 살펴보았다. 한국기계연구원에서는 3D 프린팅 기술을 바탕으로 독자적인 3D 바이오프린팅 장비를 설계 및 제작하였으며, 개발된 3D 바이오프린팅 장비를 이용하여 다양한 분야에 적용이 가능한 3D 형상의 조직공학용 스캐폴드를 제작하였다. 또한 세포와 생체재료를 3D로 직접 프린팅 할 수 있는 세포 프린팅 기술을 개발하였으며, 이는 인공장기 개발분야의 원천 기술로 조직공학 및 재생의학 분야에 3D 프린팅 기술이 활용될 수 있는 기반을 확립하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.171-172
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• 2013

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.26-30
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• 2020

In this paper, we studied the problem if the experiment number occurring in order to identify defect in scaffold. We need to change each of the 5 print factor to predict defect when printing disk type scaffold using FDM 3d printer. So then the number of scaffold print will be more than 100,000 times. This experiment number is difficult to perform in the field. In order to solve this problem, we have produced a prediction model based on machine learning multiple linear regression using print conditions and defect scaffold data for print conditions. The prediction model produced was verified through experiments. The verification confirmed that the error was less than 0.5 %. We have confirmed that satisfied within the target margin of error 5 %.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.99-103
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• 2021

Warpage defect detecting of scaffold is very important in biosensor production. Because warpaged scaffold cause problem in cell culture. Currently, there is no detection equipment to warpaged scaffold. In this paper, we produced detection model for shape warpage detection using deep learning based CNN. We confirmed the shape of the scaffold that is widely used in cell culture. We produced scaffold specimens, which are widely used in biosensor fabrications. Then, the scaffold specimens were photographed to collect image data necessary for model manufacturing. We produced the detecting model of scaffold warpage defect using Densenet among CNN models. We evaluated the accuracy of the defect detection model with mAP, which evaluates the detection accuracy of deep learning. As a result of model evaluating, it was confirmed that the defect detection accuracy of the scaffold was more than 95%.

• 대한기계학회논문집B
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• 제35권11호
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• pp.1237-1242
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• 2011

인산칼슘 재료는 하이드록시 아파타이트(Hydroxyapatite)와 트리칼슘 포스페이트(Tricalcium-phosphate)를 포함하고 있으며, 인체 골 조직의 무기성분으로 세포 독성이 없고 생체 적합한 성질을 가지고 골 전도성이 있다. 또한 두 재료가 혼합되어 있는 이상 인산칼슘(Biphasic calcium phosphate) 재료는 골 유도성이 있다고 알려져 있다. 이러한 골 조직 재생에 많은 장점을 가지고 있는 인산칼슘 재료는 파우더 타입으로, 3 차원 자유형상의 인공지지체를 제작하는 데 어려움이 있어 고분자 재료에 첨가하여 사용되었다. 본 연구에서는 자유형상 제작 기술을 이용하여 원하는 내/외부 형상을 가지는 3 차원 인산칼슘 인공지지체를 제작하고, 골 조직 재생용 인공지지체로의 사용이 적합한지를 확인하기 위해 MC3T3-E1 를 이용한 세포 증식, 골 조직 분화 실험을 수행하였다.

• 센서학회지
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• 제29권3호
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• pp.201-204
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• 2020

In this study, we fabricated and evaluated graphene composite based 3D scaffolds and planar films. The hybrid composite was prepared by mixing a calculated amount of graphene nanopowder and polydimethylsiloxane in tetrahydrofuran solution. The hybrid composite is easy to manufacture into various forms using direct printing technology or a pressing method. A 3D scaffold structure was prepared at ambient temperature with a flow rate of 240 mm/min. The nozzle pressure was maintained at 350 kPa by adjusting the viscosity of the composite material. The planar film was prepared at different thicknesses using a roll-to-roll equipment. The prepared hybrid nanocomposites were evaluated to investigate their electrical properties according to temperature and mechanical deformation. The obtained results were consistent with each other. Therefore, it can be used effectively as sensors through shape definition.

• 폴리머
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• 제38권6호
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• pp.815-819
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• 2014

조직공학에서의 인공지지체는 세포의 부착과 증식 및 분화가 잘 되어야 하고, 우수한 생체친화성 및 생분해성을 지녀야 한다. 다양한 인공지지체 제작 방법이 시도되어지고 있으며, 최근들어 3D 프린팅 기술을 이용한 방식이 활발하게 연구되어지고 있다. 폴리카프로락톤(polycaprolactone, PCL)은 낮은 녹는점을 가지고 있어 3D 프린팅하기에 우수한 생체적합 고분자 합성재료이다. 본 연구에서는 3D 프린팅 기술을 이용하여 3차원 PCL 인공지지체를 제작하였고, 지지체의 표면개질을 위해 수산화나트륨(NaOH)을 이용하였다. 표면개질된 인공지지체의 표면특성을 SEM으로 확인한 결과, 수산화나트륨을 처리한 PCL 인공지지체가 처리하지 않은 PCL 인공지지체에 비해 거칠기가 증가함을 보였으며, 접촉각 측정을 통해 친수성이 증가함을 확인하였다. In vitro 실험결과, 수산화나트륨을 처리한 PCL 인공지지체가 처리하지 않은 PCL 인공지지체에 비해 세포의 증식과 분화가 증가함을 보였고, 세포의 부착 모습은 균일하고 밀집된 형태로 부착됨을 확인하였다. 따라서 조형가공기술을 이용하여 수산화나트륨을 처리한 표면개질된 PCL 인공지지체를 제작하고 분석함으로써, 세포적합성을 통해 체내 인공지지체 개발 적용 가능성을 제시하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.56.2-56.2
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• 2012

Clinically-favored materials for bone regeneration are mainly based on bioceramics due to their chemical similarity to the mineral phase of bone. A successful scaffold in bone regeneration should have a 3D interconnected pore structure with the proper biodegradability, biocompatibility, bioactivity, and mechanical property. The pore architecture and mechanical properties mainly dependent on the fabrication process. Bioceramics scaffolds are fabricated by polymer sponge method, freeze drying, and melt molding process in general. However, these typical processes have some shortcomings in both the structure and interconnectivity of pores and in controlling the mechanical stability. To overcome this limitation, the rapid prototyping (RP) technique have newly proposed. Researchers have suggested RP system in fabricating bioceramics scaffolds for bone tissue regeneration using selective laser sintering, powder printing with an organic binder to form green bodies prior to sintering. Meanwhile, sintering process in high temperature leads to bad cost performance, unexpected crystallization, unstable mechanical property, and low bio-functional performance. The development of RP process without high thermal treatment is especially important to enhance biofunctional performance of scaffold. The purpose of this study is development of new process to fabricate ceramic scaffold at room temperature. The structural properties of the scaffolds were analyzed by XRD, FE-SEM and TEM studies. The biological performance of the scaffolds was also evaluated by monitoring the cellular activity.

• 한국기계가공학회지
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• 제20권10호
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• pp.38-43
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• 2021

Photocurable hydrogels are widely used as 3D printing materials in tissue engineering (e.g., scaffold fabrication) as well as optical fibers (or optical sensors) materials. Photocurable hydrogels can control optical and mechanical properties such as chemical or fabrication conditions. In previous research, we introduced a new 3D printing method to fabricate a freestanding overhanging hydrogel structure without supporting structure. This study was measured and analyzed the difference of the mechanical properties of the photocurable hydrogel according to the light intensity using a micro tensile tester. In practically, it was difficult to perform a direct tensile test on a micro (less than 1 mm) size fiber. In this study, the tensile test of the hydrogel fibers could be measured simply and repeatedly using a paper carrier.