Jongwan Lee
Korea Polytechnic University
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Publication
Featured researches published by Jongwan Lee.
Langmuir | 2012
Jongwan Lee; Seung Yong Lee; Jinah Jang; Young Hun Jeong; Dong-Woo Cho
Due to the numerous advantages of nanofibers, there is a strong demand in various fields for nanofibrous structures fabricated by electrospinning. However, the process is currently beset by troublesome limitations with respect to geometric and morphological control of electrospun nanofibrous mats. This study presents a direct-write electrospinning process and apparatus with improved focusing and scanning functionalities for the fabrication of various patterned thick mats and nanofibrous patterns with high geometric fidelity, supported by a number of experimental results. Consequently, various patterned nanofibrous mats were fabricated using the developed method. Additionally, the fabricated mat was successfully used for cell patterning as a bioengineering application. The proposed method is expected to significantly improve the properties and functionalities of nanofibrous mats in a variety of applications.
Applied Physics Letters | 2013
Jinah Jang; Hana Oh; Jongwan Lee; Tae-Ha Song; Young Hun Jeong; Dong-Woo Cho
Connective tissue is a factor of great importance in tissue engineering and regenerative medicine because it has a limited life but complicated mechanical properties. In this study, we present a reinforcement method of hydrogel using patterned nanofibers to mimic native connective tissues with selective engagement of load carrying constituents. We incorporated a three-dimensional nanofibrous frame fabricated using direct-write electrospinning with a hydrogel matrix. Three types of nanofiber-reinforced hydrogel composite were fabricated and their dual aspects of mechanical properties for compressive load were identified. It was demonstrated that the constructed composite had sufficient biocompatibility as well as connective tissue-like mechanical properties.
International Journal of Molecular Sciences | 2013
Seung Youl Lee; Byung Ryong Lee; Jongwan Lee; Seongjun Kim; Jung Kyung Kim; Young Hun Jeong; Songwan Jin
Electrospun nanofibrous structures provide good performance to scaffolds in tissue engineering. We measured the local diffusion coefficients of 3-kDa FITC-dextran in line patterns of electrospun nanofibrous structures fabricated by the direct-write electrospinning (DWES) technique using the fluorescence recovery after photobleaching (FRAP) method. No significant differences were detected between DWES line patterns fabricated with polymer supplied at flow rates of 0.1 and 0.5 mL/h. The oxygen diffusion coefficients of samples were estimated to be ~92%–94% of the oxygen diffusion coefficient in water based on the measured diffusion coefficient of 3-kDa FITC-dextran. We also simulated cell growth and distribution within spatially patterned scaffolds with struts consisting of either oxygen-permeable or non-permeable material. The permeable strut scaffolds exhibited enhanced cell growth. Saturated depths at which cells could grow to confluence were 15% deeper for the permeable strut scaffolds than for the non-permeable strut scaffold.
Materials | 2016
Young Hun Jeong; Jongwan Lee
Fibers and fibrous structures are used extensively in various fields due to their many advantages. Microfibers, as well as nanofibers, are considered to be some of the most valuable forms of advanced materials. Accordingly, various methods for fabricating microfibers have been developed. Electrospinning is a useful fabrication method for continuous polymeric nano- and microfibers with attractive merits. However, this technique has limitations in its ability to control the geometry of fibrous structures. Herein, advanced electrospinning with direct-writing functionality was used to fabricate microfiber patterns with ivy shoot-like geometries after experimentally investigating the effects of the process conditions on the fiber formation. The surface properties of the fibers were also modified by introducing nanoscale pores through the use of higher levels of humidity during the fabrication process.
Materials Letters | 2013
Jongwan Lee; Jinah Jang; Hana Oh; Young Hun Jeong; Dong-Woo Cho
Composites Part B-engineering | 2013
Jinah Jang; Jongwan Lee; Young-Joon Seol; Young Hun Jeong; Dong-Woo Cho
Macromolecular Materials and Engineering | 2014
Jongwan Lee; Young Hun Jeong; Dong-Woo Cho
Journal of the Korean Society of Manufacturing Process Engineers | 2014
Young Hun Jeong; Jongwan Lee; Songwan Jin
대한기계학회 춘추학술대회 | 2012
Jongwan Lee; Jinah Jang; Young Hun Jeong; Dong-Woo Cho
대한기계학회 춘추학술대회 | 2012
Hana Oh; Jongwan Lee; Young Hun Jeong