Fabrication of conductive polymer-based nanofiber scaffolds for tissue engineering applications.

Gu, Bon Kang,Kim, Min Sup,Kang, Chang Mo,Kim, Jong-Ll,Park, Sang Jun,Kim, Chun-Ho American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.10

<P>Natural and synthetic polymers, in particular those that are conductive, are of great interest in the field of tissue engineering and the pursuit of biomimetic extracellular matrix (ECM) structures for adhesion, proliferation, and differentiation of cells. In the present study, natural chitin and conductive polyaniline (PANi) blended solutions were electrospun to produce biodegradable and conductive biomimetic nanostructured scaffolds. The chitin/PANi (Chi-PANi) nanofibrous materials were characterized using field emission scanning electron microscopy, Fourier transform-infrared spectroscopy, wettability analysis, mechanical testing, and electrical conductivity measurements using a 4-point probe method. The calculated electrical conductivities of the PANi-containing nanofiber scaffolds significantly increased as the amount of PANi increased, reaching 5.21 0.28 x 10(-3) S/cm for 0.3 wt% content of the conducting polymer. In addition, the viability of human mesenchymal stem cells (hMSCs) cultured on the Chi-PANi nanofiber scaffolds in vitro was found to be excellent. These results suggest that the Chi-PANi nanofiber scaffolds have great potential for use in tissue engineering applications that involve electrical stimulation.</P>

3D Bioprinting Technologies for Tissue Engineering Applications

Gu, Bon Kang,Choi, Dong Jin,Park, Sang Jun,Kim, Young-Jin,Kim, Chun-Ho Kluwer Academic Publishers 2018 Advances in experimental medicine and biology Vol.1078 No.-

Alginate Scaffolds with Modified Micro Pores for Tissue Engineering Applications

Gu, Bon Kang,Park, Sang Jun,Kim, Min Sup,Kim, Chun Ho Trans Tech Publications, Ltd. 2015 Applied Mechanics and Materials Vol.749 No.-

<P>In this study, we developed the porous alginate (AL) scaffolds with modified pores size and distributions to actively control tissue regeneration. An addition of 5 and 10% (v/v) butanol to AL solution was effective to control pores structures of AL scaffolds. Especially, increased amount of butanol induced that proportion of smaller pores (size of around 5~10 μm) on AL scaffolds increased. Using swelling kinetics analysis, we confirmed that micro pore modified AL scaffolds show faster swelling rate than pristine scaffolds. During <I>in vitro</I> study, the enhanced viability and proliferation of human dermal fibroblasts (HDFs) were observed by the pore size and distribution from micro pore modified AL scaffolds. However, AL scaffolds added 10 % butanol with excessive proportion of smaller pores induced the decreased viability of HDFs for 7 days. From our results, AL scaffolds with modified pores structures represent a potential implants to control biological <I>in vitro</I> and <I>in vivo</I> functions in a variety of tissue engineering.</P>

3-dimensional bioprinting for tissue engineering applications

Bon Kang Gu,Dong Jin Choi,박상준,김민섭,강창모,김천호 한국생체재료학회 2016 생체재료학회지 Vol.20 No.2

The 3-dimensional (3D) printing technologies, referred to as additive manufacturing (AM) or rapid prototyping (RP), have acquired reputation over the past few years for art, architectural modeling, lightweight machines, and tissue engineering applications. Among these applications, tissue engineering field using 3D printing has attracted the attention from many researchers. 3D bioprinting has an advantage in the manufacture of a scaffold for tissue engineering applications, because of rapid-fabrication, high-precision, and customized-production, etc. In this review, we will introduce the principles and the current state of the 3D bioprinting methods. Focusing on some of studies that are being current application for biomedical and tissue engineering fields using printed 3D scaffolds.

Beneficial effect of aligned nanofiber scaffolds with electrical conductivity for the directional guide of cells

Gu, Bon Kang,Park, Sang Jun,Kim, Chun-Ho Informa UK (TaylorFrancis) 2018 Journal of Biomaterials Science. Polymer Edition Vol. No.

<P>Conducting polymer-based scaffolds receive biological and electrical signals from the extracellular matrix (ECM) or peripheral cells, thereby promoting cell growth and differentiation. Chitin, a natural polymer, is widely used as a scaffold because it is biocompatible, biodegradable, and nontoxic. In this study, we used an electrospinning technique to fabricate conductive scaffolds from aligned chitin/polyaniline (Chi/PANi) nanofibers for the directional guidance of cells. Pure chitin and random and aligned Chi/PANi nanofiber scaffolds were characterized using field emission scanning electron microscope (FE-SEM) and by assessing wettability, mechanical properties, and electrical conductivity. The diameters of aligned Chi/PANi nanofibers were confirmed to be smaller than those of pure chitin and random nanofibers owing to electrostatic forces and stretching produced by rotational forces of the drum collector. The electrical conductivity of aligned Chi/PANi nanofiber scaffolds was 91% higher than that of random nanofibers. We also studied the viability of human dermal fibroblasts (HDFs) cultured on Chi/PANi nanofiber scaffolds in vitro using a CCK-8 assay, and found that cell viability on the aligned Chi/PANi nanofiber scaffolds was 2.1-fold higher than that on random Chi/PANi nanofiber scaffolds after 7days of culture. Moreover, cells on aligned nanofiber scaffolds spread in the direction of the aligned nanofibers (bipolar), whereas cells on the random nanofibers showed no spreading (6 h of culture) or multipolar patterns (7days of culture). These results suggest that aligned Chi/PANi nanofiber scaffolds with conductivity exert effects that could improve survival and proliferation of cells with directionality.</P>

고분자 나노 섬유 형상 조절을 위한 변형된 전기방사

구본강(Bon-Kang Gu),구경완Kyung-Wan Koo) 호서대학교 공업기술연구소 2011 공업기술연구 논문집 Vol.30 No.1

전기방사 기술은 높은 전기장에서 고분자용액으로부터 연속적인 나노섬유를 얻을 수 있는 방법이다. 그러나 금속 주사기 니들로부터 방출된 고분자 용액은 강한 전기장에 의한 위핑(whipping) 운동으로 수집기에 매우 불규칙한 형태로 수집된다. 그러므로, 통상적인 전기방사를 하는 동안에 나노섬유의 형상을 조절하는 것은 매우 어렵다. 본논문에서는 변형된 전기방사 장치를 이용하여 여러 가지 다양한 방법을 통해 나노섬유의 형상 조절에 대해 소개하 고자 한다. 이러한 변형된 전기방사장치로 인해 얻어진 나노섬유는 다양한 분야에서 응용이 될 것으로 기대된다. The electrospinnmg technology enables the production of continuous polymer nanofibers rrom polymer solutions or melts in high applied electric fields. However, the electrospun nanofibers are usually randomly deposited on the collector by the whipping motion of the jet ejected from a syringe needle containing the polymeric solution. Therefore, difficulties arise for the precise control of their shape on the nano-scale during electrospinning. This paper introduced various kinds of nanofibers having different shapes by modifying the electrospinning system. This will certainly enhance the performance of products made frcan nanofibers and allow application specific modifications.

Suppressive Effect of Lignan Compound from Schizandrae fruits on Histological Injury in DSS-induced Colitic Mice

Bon-Hee Gu,Sun-Hee Lee,Sung-Won Lim,Nguyen Van Minh,Kang-Soo Lee,Dae-Ki Kim 한국실험동물학회 2010 한국실험동물학회 학술발표대회 논문집 Vol.2010 No.8

Nitrogen Use Efficiency of High Yielding Japonica Rice (Oryza Sativa L.) Influenced by Variable Nitrogen Applications

Kang, Shin-Gu,Hassan, Mian Sayeed,Ku, Bon-Il,Sang, Wan-Gyu,Choi, Min-Kyu,Kim, Young-Doo,Park, Hong-Kyu,Chowdhury, M. Khalequzzaman A.,Kim, Bo-Kyeong,Lee, Jeom-Ho The Korean Society of Crop Science 2013 한국작물학회지 Vol.58 No.3

A field study was conducted to understand nitrogen use efficiency of high yielding Japonica rice varieties under three levels of nitrogen fertilizer (90, 150 and 210 kg N $ha^{-1}$) in Iksan, Korea. Two high yielding rice varieties, Boramchan and Deuraechan, and an control variety, Dongjin2, were grown in fine silty paddy. Nitrogen use efficiencies (NUE) were 83.3, 56.3, and 41.2 in 90, 150, and 210 kg N $ha^{-1}$ fertilizer level, respectively. Total nitrogen uptake varied significantly among nitrogen levels and varieties. Variety Dongjin2 showed the highest nitrogen uptake efficiency (NUpE), while Boramchan and Deuraechan showed higher nitrogen utilization efficiency (NUtE). However, Nitrogen harvest index (NHI) was higher in Boramchan (0.58) than Deuraechan (0.57) and Dongjin2 (0.53). Rough rice yield showed linear relationship with total nitrogen uptake ($R^2$=0.72) within the range of nitrogen treatments. Boramchan produced significantly higher rough rice yield (8546 kg $ha^{-1}$) which mainly due to higher number of panicles per $m^2$ compared to Deuraechan (7714 kg $ha^{-1}$). Deuraechan showed higher number of spikelets per panicle, but showed lower yield due to lower number of panicle per $m^2$. Rice varieties showed different nitrogen uptake ability and NUE at different nitrogen level. Plant breeders and agronomist should take advantage of the significant variations and relationships among grain yield, NUpE, and NUE.

유기논 및 관행논에서 토양 내 중금속 특성 비교

구본운 ( Bon-wun Gu ),강구 ( Ku Kang ),박성직 ( Seong-jik Park ) 한국농공학회 2016 한국농공학회 학술대회초록집 Vol.2016 No.-

유기 농업은 농업생태계의 다양성과 지속 가능한 농업 생산을 위한 대안 농법으로 인식되었다. 그러나 유기농법은 관행농법과 달리 유기질 비료만을 사용하므로 환경 친화적이며 화학 비료와 달리 다량을 사용하여도 해가 없다는 인식 때문에 과량의 유기물이 시용되고 왔다. 이로 인하여 유기 농업 토양의 염류집적과 작물 생산성 저하를 불러일으켰다는 유기농업에 대한 부정적인 연구 결과도 있다. 유기농업이 환경에 미치는 영향에 대한 연구 결과는 아직 논란이 많은 실정이다. 유기농업의 환경적 가치를 정확하게 평가하고 최적관리방안을 마련하기 위해서는 추가적인 연구가 필요한 실정이다. 본 연구에서는 논 토양의 유기농법 및 관행농법의 적용에 따른 토양 내 중금속 함량의 비교를 통해서 농법에 따른 토양 환경 특성을 비교 평가하였다. 본 연구에서는 유기 농업과 관행 농업을 수행하는 논에서의 토양 특성 비교를 위해서 유기논 23개 필지와 관행논 10개 필지를 선정하였다. 유기논은 용인시 원삼면 14개 필지, 안성시 고삼면 8개 필지, 안성시 대덕면 1개 필지를 선정하였다. 유기논의 토양 특성과의 비교를 위하여 유기논 인근에 위치한 관행논으로 용인시 원삼면 4개 필지, 안성시 보개면 6개 필지를 선정하였다. 중금속 총량은 풍건시료 1 g에 HNO3 0.5 mL, HF 5 mL, HCl 2 mL를 넣고 140℃에서 2시간 동안 분해 후 As, Cd, Cr, Cu, Ni, Pb, Zn 농도를 ICP-OES로 측정하였다. 조사결과, 유기논 및 관행논 토양의 As, Cd, Ni, Pb 및 Zn의 함량은 토양오염우려기준 이하로 존재하였고, 전국 답의 중금속 평균 함량 보다도 낮았다. 유기논 토양의 중금속 함량은 관행논에 비하여 낮았지만, Zn를 제외하고 통계학적 차이는 없는 것으로 나타났다. 따라서 유기논 토양이 관행논 토양에 비하여 중금속 농도 측면에서 그 차이는 크지 않지만 양호하다고 판단된다.

폐콘크리트를 이용한 수중 불소의 제거 및 흡착 특성

구본운 ( Bon Wun Gu ),강구 ( Ku Kang ),박성직 ( Seong Jik Park ) 한국수처리학회 2015 한국수처리학회지 Vol.23 No.6

Crushed concrete was used for the removal of fluoride from aqueous solution and its adsorption characteristics were investigated. Adsorption experiments have been conducted in batch conditions. From the experiments using crushed concrete thermally treated at different temperatures, it was found that thermal treatment on crushed concrete had a deleterious effect on the fluoride removal. Kinetic sorption test and model analysis showed that fluoride adsorption to crushed concrete was dependent on chemisorption. Equilibrium adsorption results followed the Langmuir adsorption isotherm model with adsorption capacity of 28.50 mg/g. The estimated thermodynamic parameters (ΔH°, ΔS° and ΔG°) indicated that the adsorption was spontaneous and endothermic. Additional batch experiments indicated that fluoride adsorption to crushed concrete was the highest at pH 3 and decreased with increasing pH. The effect of other anion on fluoride removal by crushed concrete followed the order of PO4^3- > HCO3- > SO4^2- □ NO3-. This study demonstrated that crushed concrete was proven to be an effective adsorbent with high adsorption capacity of fluoride and its use for the fluoride removal is economical and environmentally sustainable.