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Lim, Bumhee,Baek, Byungyeob,Jang, Kyungkuk,Lee, Na Keum,Lee, Ji Hye,Lee, Yeongcheol,Kim, Jinwoo,Kang, San Won,Park, Jaehyun,Kim, Suzi,Kang, Nae-Won,Hong, Suckchang,Kim, Dae-Duk,Kim, Ikyon,Hwang, Hyons Elsevier 2019 Dyes and pigments Vol.169 No.-
<P><B>Abstract</B></P> <P>Iron-selective turn-on sensors are indispensable tools for understanding iron-related cell death processes and human diseases. In this study, we report a novel class of fluorescent sensors derived from an indolizino[3,2-<I>c</I>]quinoline scaffold that exhibit high selectivity for Fe<SUP>3+</SUP> over other biologically abundant cations in cells, including Fe<SUP>2+</SUP>, Al<SUP>3+</SUP>, Zn<SUP>2+</SUP>, and Mn<SUP>2+</SUP>. <B>IQ18</B> works as a ratiometric sensor with a <I>K</I> <SUB>d</SUB> value of 7.1 × 10 <SUP>−7</SUP> M and a detection limit of 5.2 nM in ethanol, whereas <B>IQ44</B> displays fluorescence enhancement upon binding with Fe<SUP>3+</SUP> in both ethanol and water. In aqueous solution, <B>IQ44</B> exists as 150-nm nanoparticles. The suppressed fluorescent emission of <B>IQ44</B> nanoparticles in water is switched on in response to Fe<SUP>3+</SUP>, working as a turn-on nanoparticle sensor. Structure-property relationship analysis with IQ derivatives revealed that the thiophene ring confers selectivity for Fe<SUP>3+</SUP>. By installing thiophene in <B>IQ44</B> as a selectivity-tuning handle, fluorescence in the presence of Fe<SUP>3+</SUP> resulting from restriction of intramolecular rotation (RIR) and increased torsion angle induced by iron demonstrated that <B>IQ44</B> is specifically localized in lysosomes, where it recognizes cellular Fe<SUP>3+</SUP> in live cells, as determined using confocal microscopy. In addition, the increased fluorescent puncta of <B>IQ44</B> in the presence of Fe<SUP>3+</SUP> colocalized well with the RFP-tagged LC3 proteins (pmRFP-LC3), enabling the detection of the autophagy process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed novel indolizino[3,2-<I>c</I>]quinoline (IQ)-based fluorescent sensors (<B>IQ18</B> and <B>IQ44</B>) for Fe<SUP>3+</SUP>. </LI> <LI> <B>IQ18</B> works as a ratiometric sensor, whereas <B>IQ44</B> works as a ∼150 nm turn-on nanoparticle sensor for Fe<SUP>3+</SUP> in water. </LI> <LI> <B>IQ44</B> is specifically localized in lysosomes, where it recognizes cellular Fe<SUP>3+</SUP> in live cells. </LI> </UL> </P>
Kwon, Soonbum,Lee, Yeongcheol,Jung, Youngeun,Kim, Ju Hee,Baek, Byungyeob,Lim, Bumhee,Lee, Jungeun,Kim, Ikyon,Lee, Jeeyeon Elsevier 2018 European journal of medicinal chemistry Vol.148 No.-
<P><B>Abstract</B></P> <P>To achieve efficient photodynamic activity, substantial effort has been dedicated to precise control of the intracellular localization of current photosensitizers (PSs). Given the extremely small radius of action of singlet oxygen, the direct targeting of PSs to the mitochondria is expected to greatly enhance the photodynamic therapy (PDT) activity. Here, we report mitochondria-targeting 6-(furan-2-yl)- and 6-(thiophen-2-yl) indolizino[3,2<I>-c</I>]quinolines (IQs) as novel PSs. IQ derivatives containing 5-membered heterocyclic aromatic rings were synthesized, and their photophysical properties as PSs were characterized. The anticancer potentials of <B>2a</B>-<B>2f</B> were investigated using various cancer cell lines, and they exhibited dose-dependent and light exposure time-dependent cytotoxicity. Among the synthesized compounds, <B>2b</B>, which contains a furan ring, showed dual functions as an imaging probe as well as a PS. Real-time confocal fluorescence images revealed the mitochondrial localization of <B>2b</B> as a primary site of photodamage in live cells. Targeted reactive oxygen species (ROS)-generation capabilities and the photoinduced DNA cleavage of IQs led to mitochondrial dysfunction and photoinduced apoptosis via the intrinsic pathway. 3D RI tomograms of individual live HeLa cells treated with <B>2b</B> showed that the progress of photoinduced apoptosis was affected by the PS concentration and light irradiation time. The studied IQs (<B>2b, 2d,</B> and <B>2e</B>) are expected to serve as a new class of heavy-atom-free PSs with low molecular weights less than 350.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 6-(furan-2-yl)- and 6-(thiophen-2-yl) indolizino[3,2<I>-c</I>]quinolines (<B>2a</B>-<B>2f</B>) were synthesized as novel photosensitizers (PSs). </LI> <LI> Compounds <B>2a</B>-<B>2f</B> exhibited dose-dependent and light exposure time-dependent cytotoxicity, demonstrating anticancer potentials in cancer cells. </LI> <LI> Real-time confocal fluorescence images revealed the mitochondrial localization of <B>2b</B> as a primary site of photodamage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Peer-to-Peer 응용을 위한 모바일 에드혹 라우팅 프로토콜
송점기(Jeomki Song),정홍종(Hongjong Jeong),김동균(Dongkyun Kim),김병엽(Byungyeob Kim) 한국정보과학회 2004 한국정보과학회 학술발표논문집 Vol.31 No.2Ⅲ
최근 MANET(Mobile Ad-hoc Networks)에서의 P2P 응용을 이용한 서비스 개발이 활발히 진행 중이다. 이와 함께 에드혹 환경에서의 적합한 P2P 모델에 관한 연구로 기존 P2P 모델인 Gnutella, DHT등을 에드혹에 적용한 연구 역시 활발히 이루어지고 있다. 본 논문에서는 on-demand 방식의 에드혹 라우팅 프로토콜인 AODV(Ad-hoc On-Demand Distance Vector)상에서, 대표적인 P2P 응용인 Gnutella의 동작 과정을 통해 P2P 응용이 갖는 문제점을 분석하고, P2P 응용의 검색과정에서 발생하는 오버헤드를 줄이기 위한 방안을 제안한다. 그리고 위의 연구 결과를 바탕으로 현재 IPv6 AODV상에서 MANET을 위한 응용인 DiPP(Fully Distributed Peer-to-Peer) 시스템을 구현한다. DiPP 시스템은 MANET상에서의 메신저와 파일 공유를 위한 기능을 위해 동작한다.