Water-soluble, lignin-derived carbon dots with high fluorescent emissions and their applications in bioimaging

Myint, Aye Aye,Rhim, Won-Kyu,Nam, Jwa-Min,Kim, Jaehoon,Lee, Youn-Woo Elsevier 2018 Journal of industrial and engineering chemistry Vol.66 No.-

<P><B>Abstract</B></P> <P>We report the synthesis of water-soluble and environmentally friendly fluorescent carbon dots (CDs) using the renewable resource lignin as a precursor, which is a waste emitted from pulp and paper industries and lignocellulosic biofuel production, using a compressed liquid CO<SUB>2</SUB> antisolvent method followed by carbonization and chemical oxidation with an acid mixture (H<SUB>2</SUB>SO<SUB>4</SUB>:HNO<SUB>3</SUB> =1:3, v/v) at 90°C for 8, 16, and 24h. The as-synthesized CDs emitted bright yellow fluorescence (FL) under argon laser excitation at 458nm with excitation-wavelength-independent and excitation-wavelength-dependent FL emission characteristics. Moreover, the CDs exhibited excellent stability in a highly concentrated NaCl solution, photostability with pH-dependent FL emission activities, and cellular imaging capability with very low cytotoxicity. Notably, the FL emission intensities of the as-synthesized CDs increased with longer reaction times, indicating high degree of oxidation on the CD surface and consequently, high quantum yield of 13% was achieved. Therefore, the as-synthesized CDs can be used as promising fluorescent probes for bioimaging applications <I>in vitro</I> and <I>in vivo</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Water-soluble fluorescent carbon dots (CDs) synthesized from kraft lignin. </LI> <LI> CDs exhibited pH-dependent fluorescence (FL) emission and high salt/photo stability. </LI> <LI> FL emission intensities increased with longer reaction times. </LI> <LI> A high quantum yield of 13% resulted in the CDs synthesized for 24h. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Influence of membrane surface properties on the behavior of initial bacterial adhesion and biofilm development onto nanofiltration membranes

Myint, Aye Aye,Lee, Wonil,Mun, Sungmin,Ahn, Chang Hoon,Lee, Seockheon,Yoon, Jeyong Taylor Francis 2010 BIOFOULING -CHUR- Vol.26 No.3

<P> In order to investigate biofouling problems, the fundamental behaviors of initial bacterial adhesion and biofilm development on four different nanofiltration (NF) membranes were evaluated using Pseudomonas aeruginosa PAO1 as a model bacterial strain. Initial cell adhesion was considerably higher on an aromatic polyamide-based NF membrane with a hydrophobic and rough surface, whereas cell aggregation on a polypiperazine-based NF membrane with a relatively hydrophilic and smooth surface was lower. Moreover, significant differences in the structural heterogeneity of the biofilms were observed among the four NF membranes. This study shows that the surface roughness and hydrophobicity of a membrane play an important role in determining initial cell adhesion, aggregation and favorable localization sites for colony formation. In addition, it was found that biofilm development was strongly influenced by the surface morphology of a membrane.</P>

NF 멤브레인에서 실시간 박테리아 부착능 분석

( Aye Aye Myint ),이원일 ( Won Il Lee ),문성민 ( Sung Min Mun ),안창훈 ( Chang Hoon Ahn ),윤제용 ( Je Yong Yoon ) 한국물환경학회 2009 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2009 No.-

Water-soluble, lignin-derived carbon dots with high fluorescent emissions and their applications in bioimaging

Aye Aye Myint,임원규,남좌민,김재훈,이윤우 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

We report the synthesis of water-soluble and environmentally friendly fluorescent carbon dots (CDs) using the renewable resource lignin as a precursor, which is a waste emitted from pulp and paper industries and lignocellulosic biofuel production, using a compressed liquid CO2 antisolvent method followed by carbonization and chemical oxidation with an acid mixture (H2SO4:HNO3 = 1:3, v/v) at 90 °C for 8, 16, and 24 h. The as-synthesized CDs emitted bright yellow fluorescence (FL) under argon laser excitation at 458 nm with excitation-wavelength-independent and excitation-wavelength-dependent FL emission characteristics. Moreover, the CDs exhibited excellent stability in a highly concentrated NaCl solution, photostability with pH-dependent FL emission activities, and cellular imaging capability with very low cytotoxicity. Notably, the FL emission intensities of the as-synthesized CDs increased with longer reaction times, indicating high degree of oxidation on the CD surface and consequently, high quantum yield of 13% was achieved. Therefore, the as-synthesized CDs can be used as promising fluorescent probes for bioimaging applications in vitro and in vivo.

One pot synthesis of environmentally friendly lignin nanoparticles with compressed liquid carbon dioxide as an antisolvent

Myint, Aye Aye,Lee, Hun Wook,Seo, Bumjoon,Son, Won-Su,Yoon, Junho,Yoon, Tae Jun,Park, Hee Jeong,Yu, Jihyun,Yoon, Jeyong,Lee, Youn-Woo The Royal Society of Chemistry 2016 GREEN CHEMISTRY Vol.18 No.7

<P>Nanoparticles from commercial kraft lignin were developed using a facile, one pot green technology of a compressed CO2 antisolvent. N,N-Dimethylformamide (DMF) was employed as an organic solvent to prepare the lignin solution. The effects of various process parameters: temperature, pressure, solution flow rate and initial solution concentration, on the product yields, morphology, size, size distribution, surface area and textural properties of the particles were investigated by FESEM, HRTEM analyses and BET analyzers, and their formation mechanisms were deduced by the solubility behavior of lignin with liquid CO2 and DMF in the operating system. Moreover, the quality of lignin nanoparticles were elucidated by ATR-FTIR, XPS, XRD, DSC, TG/DTA and UV-vis measurements. This study showed that as the temperature and lignin concentration increased, and the pressure and solution flow rate decreased, the degree of particle aggregation/coalescence and the size increased along with the broader size distribution. In particular, the coalescence of particles was strongly influenced by the operational pressure, and even more significant with the increasing temperature. As a result, uniform, quasi-spherical nanoparticles with a mean particle diameter of 38 nm were obtained at 280.2 K, 15.0 MPa, and 0.06 kg h(-1) of the solution flow rate and 5.3 wt% of the initial lignin concentration. Besides, the lignin nanoparticles have a relatively high BET surface area (nearly 92 m(2) g(-1)) which primarily consisted of mesopores, and exhibited higher UV absorbing and dispersion stability, enhanced solubility, and homogeneous thermal degradation activity as compared with the raw lignin. Noteworthily, their biodegradable and biocompatible character may render them a candidate for applications in cosmetics, health and drug delivery systems.</P>

Effect of compressed liquid CO₂ antisolvent treatment on the synthesis of hierarchically porous nanocarbon from kraft lignin

Myint, Aye Aye,Seo, Bumjoon,Son, Won-Su,Yoon, Junho,Shin, Naechul,Kim, Jaehoon,Lee, Youn-Woo Elsevier 2017 The Journal of supercritical fluids Vol.123 No.-

<P><B>Abstract</B></P> <P>Carbon nanoparticles with hierarchical micro/mesoporous structure were developed from a commercial kraft lignin using a facile, one-pot green technology of a compressed liquid CO<SUB>2</SUB> antisolvent treatment, followed by thermostablization and carbonization processes. The as-synthesized carbon nanoparticles were systematically characterized by investigating the surface properties of morphology, particle size, and chemical states with FESEM, HRTEM and XPS, respectively; surface areas and porous structures with BET analyzer; crystalline state with XRD and Raman spectroscopy; chemical features with FTIR; and elemental compositions with an elemental analyzer. The results indicated that the carbon nanoparticles fabricated from the smallest quasi-spherical lignin nanoparticles contained high nanocrystalline and amorphous carbons levels. The enhanced phenolic, carbonyl, and carboxylic functional groups on the particle surface promoted the dispersibility of the particles in deionized water. The size and morphology of the lignin precursor particles significantly affected the fabrication of the carbon nanoparticles by carbonization. The experiment suggested that such dispersible and porous carbon nanoparticles could be applicable in the fields of energy, biotechnology, and environmental pollution control.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We have developed hierarchically porous carbon nanoparticles from kraft lignin. </LI> <LI> The carbon nanoparticles’ surfaces contain enhanced oxygen-containing functional groups. </LI> <LI> They have high surface areas and show good dispersibility in deionized water. </LI> <LI> The size and morphology of lignin precursors are important in the carbonization step. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of the COX-2 Inhibitor Celecoxib on Behavioural and Immune Changes in an Olfactory Bulbectomised Rat Model of Depression

Myint, Aye Mu,Steinbusch, Harry W.M.,Goeghegan, Liam,Luchtman, Dirk,Kim, Yong Ku,Leonard, Brian E. Karger 2007 NEUROIMMUNOMODULATION -BASEL- Vol.14 No.2

<P><I>Background:</I> The olfactory bulbectomised (OBX) rat model is a chronic model of depression in which behavioural and neuroimmunoendocrine changes are reversed only after chronic antidepressant treatment. The cyclooxygenase 2 (COX-2) inhibitor celecoxib has been shown to improve the depressive symptoms in patients with major depression. <I>Methods:</I> The association between blood and brain immunological and behavioural changes in chronic treatment with COX-2 inhibitor was explored in the OBX rats and their sham-operated controls. <I>Results:</I> The OBX group showed significantly higher locomotor activity than the other groups in the first 5 min in the open field. In the home cage emergence test, the OBX group showed a significantly shorter latency period compared to the sham group (z = -3.192, p = 0.001) but there was no difference between the other three groups. In the hypothalamus, the OBX group had a significantly higher interleukin 1β (IL-1β) concentration than the OBX + celecoxib group (z = -1.89, p = 0.05) as well as a significantly higher IL-10 concentration (z = -1.995, p = 0.046). In the prefrontal cortex, the OBX group showed significantly higher concentrations of tumour necrosis factor α (z = -2.205, p = 0.028) and IL-1β (z = -3.361, p = 0.001) than the OBX + celecoxib group, but a significantly lower concentration of IL-10 (p = -3.361, p = 0.001) than the OBX + celecoxib group. <I>Conclusions:</I> The results of this study supported the potential therapeutic role of the COX-2 inhibitor celecoxib. It is possible that the behavioural changes following the chronic administration of celecoxib to the OBX rats are associated with an attenuation of the increase in the pro-inflammatory cytokines in the brain.</P><P>Copyright © 2007 S. Karger AG, Basel</P>

Extracting the motion pattern of the players from a video stream of the football game

Aye Pa Pa Mya,Thin Lai Lai Thein,Myint Myint sein 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Complete Decarboxylation of Soybean Oil to Fuel-range Hydrocarbons with Sub-/Supercritical Water

최종호,( Aye Aye Myint ),김재훈 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

Characterizing Helicobacter pylori cagA in Myanmar

( Thein Myint ),( Muhammad Miftahussurur ),( Ratha-korn Vilaichone ),( New Ni ),( Than Than Aye ),( Phawinee Subsomwong ),( Tomohisa Uchida ),( Varocha Mahachai ),( Yoshio Yamaoka ) 대한간학회 2018 Gut and Liver Vol.12 No.1

Background/Aims: Differences in the Helicobacter pylori infection rate are not sufficient to clarify the dissimilarity of gastric cancer incidence between Myanmar and its neighboring countries. To better understand this trend, the H. pylori virulence gene cagA was characterized in Myanmar. Methods: Glutamate-proline-isoleucine-tyrosine-alanine (EPIYA) patterns and CagA multimerization (CM) motifs of cagA genotypes were examined by performing polymerase chain reactions and DNA sequencing. Results: Of 69 tested H. pylori strains, cagA-positive patients had significantly more severe histological scores in their antrum than cagA-negative patients. Sequence analysis revealed that 94.1% of strains had Western-type cagA containing an EPIYA motif (92.6%) or EPIYT motif (6.4%). The intestinal metaplasia scores in the antral of patients infected with the ABC and ABCC types of cagA were significantly higher than those of patients with AB-type cagA. Interestingly, in patients infected with H. pylori, 46.3% of strains with three EPIYA motifs contained two identical Western-typical CM motifs, and these patients showed significantly higher antrum inflammation scores than patients infected with two identical nontypical-CM motif strains (p=0.02). Conclusions: In Myanmarese strains, Western-type cagA was predominant. The presence of CM motifs and the proportion of multiple EPIYA-C segments might partially explain the intermediate gastric cancer risk found in Myanmar. (Gut Liver 2018;12:51-57)