A Graphene-Based Platform for the Assay of Duplex-DNA Unwinding by Helicase

Jang, Hongje,Kim, Young-Kwan,Kwon, Hyun-Mi,Yeo, Woon-Seok,Kim, Dong-Eun,Min, Dal-Hee WILEY-VCH Verlag 2010 Angewandte Chemie Vol.49 No.33

<B>Graphic Abstract</B> <P>Time to unwind: Graphene oxide (GO) enables the quantitative measurement of helicase-dependent double-stranded DNA (dsDNA) unwinding activity in real time. GO selectively binds to unwound fluorescent-dye-labeled single-stranded DNA and quenches its fluorescence (see picture). The helicase activity is monitored by following the change in fluorescence. <img src='wiley_img_2010/14337851-2010-49-33-ANIE201001332-content.gif' alt='wiley_img_2010/14337851-2010-49-33-ANIE201001332-content'> </P>

A Graphene-Based Platform for the Assay of Duplex-DNA Unwinding by Helicase

Jang, Hongje,Kim, Young-Kwan,Kwon, Hyun-Mi,Yeo, Woon-Seok,Kim, Dong-Eun,Min, Dal-Hee WILEY-VCH Verlag 2010 Angewandte Chemie Vol.122 No.33

<B>Graphic Abstract</B> <P>Mit bloßen Auge zu erkennen: Mithilfe von Graphenoxid (GO) kann die Helicase-abhängige Entwindung doppelsträngiger DNA (dsDNA) quantitativ und in Echtzeit verfolgt werden. GO bindet selektiv an entwundene fluoreszenzmarkierte einzelsträngige DNA und löscht die Fluoreszenz (siehe Bild). Die Helicaseaktivität wird über die Fluoreszenzänderung registriert. <img src='wiley_img_2010/00448249-2010-122-33-ANGE201001332-content.gif' alt='wiley_img_2010/00448249-2010-122-33-ANGE201001332-content'> </P>

Self-assembled Monolayer Mediated Surface Environment Modification of Poly(vinylpyrrolidone)-Coated Hollow Au–Ag Nanoshells for Enhanced Loading of Hydrophobic Drug and Efficient Multimodal Therapy

Jang, Hongje,Kim, Dong-Eun,Min, Dal-Hee American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.23

<P>Hollow Au-Ag bimetallic nanoshell possessing hydrophobic interior space and hydrophilic exterior surface was prepared and its application as a chemo-thermo-gene therapeutic agent based on its high payload of multiple drugs having different water solubility was demonstrated. The multifunctional drug delivery system is based on the hydrophobic interior created by the self-assembled monolayer (SAM) of hexanethiol onto the inner surface of the hollow metallic nanoshells whereas the outer surface was mostly coated by hydrophilic biocompatible polymer. The nanoshells having surface environment modified by hexanethiol SAMs provided high capacity both for hydrophilic DNAzyme (Dz) to induce gene silencing and for hydrophobic SN38 (7-ethyl-10-hydroxycamptothecin), anticancer drug. The release of the loaded Dz and SN38 was independently triggered by an acidic environment and by photothermal temperature elevation upon irradiation, respectively. The chemo-thermo-gene multitherapy based on the present nanoshells having modified surface environment showed high efficacy in quantitative cell-based assays using Huh7 human liver cell containing hepatitis C viral NS3 gene replicon RNA.</P>

Development and application of a UPLC method for studying infl uence of phenological stage on chemical composition of Scutellariae Radix

Hua Li,Hongjing Dong,Jianchun Su,Bin Yang 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.9

The influence of phenological stages onchemical composition of Scutellariae Radix (SR), theroot of Scutellaria baicalensis Georgi, was investigated. In order to deal with a large quantity of samples, arapid ultra-performance liquid chromatographic (UPLC)was first developed and validated for the simultaneousquantification of five flavonoids, namely baicalin(baicalein-7-O-b-D-glucuronide, BG), wogonoside(wogonin-7-O-b-D-glucuronide, WG), baicalein (BA),wogonin (WO), oroxylin A (OA) in the samples. Goodlinearity was obtained in the range of 0.742–389 ng(r2[0.9999) and satisfactory recoveries were obtained(101.72–104.56 %) with the RSD value below 5.0 %,for all analytes. Also, extraction conditions were optimizedto obtain maximum extractive contents of thefive flavonoids. Content variations of the five activeingredients in 225 samples from three different originswere investigated in five major phenological periods. Itwas found that the effect of phenology on the contentsof the tested five flavonoids was similar in the threeorigins. The contents of flavone O-glycosides, i.e., BGand WG accumulated to the highest level in leafexpansion period, while flavonoid aglycones, i.e., BA, WO and OA appeared a maximum concentration inflowering period. The UPLC method established in thisstudy was rapid and of good accuracy, repeatability andresolution, and hence can assist in the quality control ofSR.

Extraction of parishin B and parishin C from Gastrodiae Rhizoma by subcritical water technology

Guozhen Wu,Hongjing Dong,Jia Li,Lanping Guo,Yan Cheng,Yanling Geng,Xiao Wang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

Subcritical water extraction (SWE) was used to extract bioactive parishin B (PB) and parishin C (PC) fromGastrodiae Rhizoma. Extraction conditions were optimized by Box-Behnken design (BBD) of responsesurface methodology (RSM). The highest yield of PB was 7.46 ± 0.18 mg/g when the solid/liquid ratio(SLR) was 4.5 mg/mL at an extraction temperature of 118 C and extraction time of 50 min, and the highestyield of PC was 5.27 ± 0.07 mg/g when the SLR was 22 mg/mL at an extraction temperature of 145 Cand extraction time of 23 min. Compared with heating reflux extraction the yield of PB was about 1.3times higher, and that of PC about 2.6 times higher; Compared with ultrasound assisted extraction theyield of PB was about 3 times higher, and that of PC about 6 times higher. Degradation of parishin Aby SWE showed that the increasing mechanism of PB and PC mainly attributed to the conversion of PAinto PB and PC. This study suggests that SWE was an efficient and green way to extract natural productswith greater values.

Exfoliated MXene as a mediator for efficient laser desorption/ionization mass spectrometry analysis of various analytes

Chae, Ari,Jang, Hongje,Koh, Dong-Yeun,Yang, Cheol-Min,Kim, Young-Kwan Elsevier 2020 Talanta Vol.209 No.-

<P><B>Abstract</B></P> <P>The exfoliated MXene (e-MXene) is systematically investigated as a mediator for laser desorption/ionization time-of-flight mass spectrometry (LDI-MS) analysis. Whereas un-exfoliated MXene has no activity for LDI-MS analysis, the e-MXene presents a high resolution, salt-tolerance and efficiency for LDI-MS analysis of various small molecules regardless of their polarity, aromaticity and molecular weight owing to its physicochemical properties such as high laser energy absorption, electrical conductivity and photothermal conversion. Based on our findings, it is clearly confirmed that e-MXene is a promising material for the development of an efficient platform for LDI-MS analysis of small molecules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The exfoliated MXene is applied to laser desorption/ionization time-of-flight mass spectrometry (LDI-MS) analysis for the first time. </LI> <LI> Various small molecules are successfully detected with the exfoliated MXene without background interference. </LI> <LI> Organic pollutants are successfully detected by using exfoliated MXene with LDI-MS analysis. </LI> <LI> High LDI-MS efficiency of MXene is achieved by its high laser energy absorption capacity, electrical conductivity, and photothermal conversion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

FREE-FLOATING PLANETS, THE EINSTEIN DESERT, AND 'OUMUAMUA

Gould, Andrew,Jung, Youn Kil,Hwang, Kyu-Ha,Dong, Subo,Albrow, Michael D.,Chung, Sun-Ju,Han, Cheongho,Ryu, Yoon-Hyun,Shin, In-Gu,Shvartzvald, Yossi,Yang, Hongjing,Yee, Jennifer C.,Zang, Weicheng,Cha, S The Korean Astronomical Society 2022 Journal of The Korean Astronomical Society Vol.55 No.5

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.