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Polypyrrole-incorporated conductive hyaluronic acid hydrogels
Jongcheol Yang,최고은,Sumi Yang,Hyerim Jo,이재영 한국생체재료학회 2016 생체재료학회지 Vol.20 No.4
Background: Hydrogels that possess hydrophilic and soft characteristics have been widely used in various biomedical applications, such as tissue engineering scaffolds and drug delivery. Conventional hydrogels are not electrically conductive and thus their electrical communication with biological systems is limited. Method: To create electrically conductive hydrogels, we fabricated composite hydrogels of hyaluronic acid and polypyrrole. In particular, we synthesized and used pyrrole-hyaluronic acid-conjugates and further chemically polymerized polypyrrole with the conjugates for the production of conductive hydrogels that can display suitable mechanical and structural properties. Results: Various characterization methods, using a rheometer, a scanning electron microscope, and an electrochemical analyzer, revealed that the PPy/HA hydrogels were soft and conductive with ~ 3 kPa Young’s modulus and ~ 7.3 mS/cm conductivity. Our preliminary in vitro culture studies showed that fibroblasts were well attached and grew on the conductive hydrogels. Conclusion: These new conductive hydrogels will be greatly beneficial in fields of biomaterials in which electrical properties are important such as tissue engineering scaffolds and prosthetic devices.
조피볼락(Sebastes schlegelii) Interferon Regulatory Factor 8 (IRF8)의 분자유전학적 특성 및 발현 분석
양혜림 ( Hyerim Yang ),권혁재 ( Hyukjae Kwon ),이성도 ( Seongdo Lee ),( S. D. N. K Bathige ),김명진 ( Myoung-jin Kim ),이제희 ( Jehee Lee ) 한국수산과학회 2017 한국수산과학회지 Vol.50 No.3
Interferon regulatory factor 8 (IRF8) is essential for the development of B and T cells, as well as for the activity of den-dritic cells and macrophages. We performed molecular characterization of IRF8 from rock fish, Sebastes schlegelii (Ss), and investigated the spatial and temporal profile of mRNA expression after challenge with lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (poly I:C), or Streptococcus iniae. The full-length cDNA sequence of SsIRF8 was 1,657 bp, containing an ORF of 1,266 bp. The gene had a predicted molecular mass of 47.7 kDa and an isoelec-tric point of 5.99. The amino acid sequence coded by this gene showed the highest degree of identity (90.8%) and similarity (96.2%) with IRF8 from Oplegnathus fasciatus. The SsIRF8 mRNA was expressed ubiquitously, at varying levels, with the highest level of expression observed in the spleen. To confirm the role of SsIRF8 in mediating the immune response, we measured SsIRF8 mRNA expression in the splenic tissue at different time points after injection with LPS, poly I:C, or S. iniae. The qRT-PCR results showed that SsIRF8 mRNA expression in the poly I:C-injected group was highly upregulated 6 hr after exposure (P<0.05). Expression of SsIRF8 mRNA in the S. iniae-injected group peaked at 24 hr. These results suggest that SsIRF8 might be important in regulating the strength of the rockfish immune response to immunostimulatory agents.
Jo, Hyerim,Sim, Myeongbu,Kim, Semin,Yang, Sumi,Yoo, Youngjae,Park, Jin-Ho,Yoon, Tae Ho,Kim, Min-Gon,Lee, Jae Young Elsevier 2017 Acta Biomaterialia: structure-property-function re Vol.48 No.-
<P><B>Abstract</B></P> <P>Graphene and graphene derivatives, such as graphene oxide (GO) and reduced GO (rGO), have been extensively employed as novel components of biomaterials because of their unique electrical and mechanical properties. These materials have also been used to fabricate electrically conductive biomaterials that can effectively deliver electrical signals to biological systems. Recently, increasing attention has been paid to electrically conductive hydrogels that have both electrical activity and a tissue-like softness. In this study, we synthesized conductive graphene hydrogels by mild chemical reduction of graphene oxide/polyacrylamide (GO/PAAm) composite hydrogels to obtain conductive hydrogels. The reduced hydrogel, r(GO/PAAm), exhibited muscle tissue-like stiffness with a Young’s modulus of approximately 50kPa. The electrochemical impedance of r(GO/PAAm) could be decreased by more than ten times compared to that of PAAm and unreduced GO/PAAm. <I>In vitro</I> studies with C2C12 myoblasts revealed that r(GO/PAAm) significantly enhanced proliferation and myogenic differentiation compared with unreduced GO/PAAm and PAAm. Moreover, electrical stimulation of myoblasts growing on r(GO/PAAm) graphene hydrogels for 7days significantly enhanced the myogenic gene expression compared to unstimulated controls. As results, our graphene-based conductive and soft hydrogels will be useful as skeletal muscle tissue scaffolds and can serve as a multifunctional platform that can simultaneously deliver electrical and mechanical cues to biological systems.</P> <P><B>Statement of Significance</B></P> <P>Graphene-based conductive hydrogels presenting electrical conductance and a soft tissue-like modulus were successfully fabricated via mild reduction of graphene oxide/polyacrylamide composite hydrogels to study their potential to skeletal tissue scaffold applications. Significantly promoted myoblast proliferation and differentiation were obtained on our hydrogels. Additionally, electrical stimulation of myoblasts via the graphene hydrogels could further upregulate myogenic gene expressions. Our graphene-incorporated conductive hydrogels will impact on the development of new materials for skeletal muscle tissue engineering scaffolds and bioelectronics devices, and also serve as novel platforms to study cellular interactions with electrical and mechanical signals.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
위혜림(Hyerim Wi),김세영(Seyoung Kim),김호영(Hoyoung Kim),유하진(Hajin Yu),박지연(Jiyeon Park),송예슬(Yeseul Song),양아영(Ayoung Yang),유혜민(Hyemin Yoo) 성신여자대학교 한국지리연구소 2015 應用地理 Vol.- No.32
전 세계적으로 지구 온난화로 인해 지구의 환경이 변화하고 있다. 이는 인간의 활동이 주된 원인으로 꼽히고 있다. 결국 이러한 변화는 모든 생명체에 막대한 영향을 끼치고, 특히 식생에서의 큰 변화를 낳을 것으로 예상된다. 따라서 본 연구는 앞서 발간된 여러 논문들을 바탕으로 기온과 강수량에 초점을 맞춰 세계와 한국의 기후 변화를 알아보고 식생의 분포 변화를 분석하는 형식으로 이루어졌다. 식생의 변화는 분포지가 점차 확대되고 있는 난대성 작물과 분포지가 점점 축소되고 있는 냉대성 작물의 대표적인 작물을 선택하여 연구를 진행하였다. 난대성 작물에서는 대나무와 차나무, 냉대성 작물에서는 배추나무, 구상나무, 사과나무, 그리고 풍혈을 선정하여 각각의 작물 특성과 이에 따른 재배지의 변화를 예측하였다. The environment of the earth is changing globally because of the global warming. The basic cause of this phenomenon is human activities. It is expected that this change will eventually affect all living things, especially vegetation will be affected a lot by this change. Therefore this study investigated the climate change of the world and the South Korea focusing on temperature and precipitation based on preceding research data, and analyzed the change of vegetation distribution. It was proceeded by choosing some samples of flora of warm climate expanding its realm and some samples of flora of subarctic climate decreasing its realm. There are bamboo and tea plant in samples of warm climate and napa cabbage, Korean fir, apple trees and wind-hole in samples of subarctic climate. This study predicted the natures and changes of plantation of each samples.