Fabrication of novel compound SERS substrates composed of silver nanoparticles and porous gold nanoclusters: A study on enrichment detection of urea

Li, Yali,Li, Qianwen,Sun, Chengbin,Jin, Sila,Park, Yeonju,Zhou, Tieli,Wang, Xu,Zhao, Bing,Ruan, Weidong,Jung, Young Mee Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.427 No.2

<P><B>Abstract</B></P> <P>A new type of surface-enhanced Raman scattering (SERS) substrate was fabricated through the layer-by-layer self-assembly of silver nanoparticles (AgNPs, av. 45nm in diameter) and porous gold nanoclusters/nanoparticles (AuNPs, av. 143nm in diameter). The development of the porosity of the AuNPs was investigated, and successful SERS applications of the porous AuNPs were also examined. As compared with AgNP films, the enhancement factor of Ag-Au compound substrates is increased 6 times at the concentration of 10<SUP>−6</SUP> M. This additional enhancement contributes to the trace-amount-detection of target molecules enormously. The contribution is generated through the increase of the usable surface area arising from the nanoscale pores distributed three-dimensionally in the porous AuNPs, which enrich the adsorption sites and hot spots for the adsorption of probe molecules, making the developed nanofilms highly sensitive SERS substrates. The substrates were used for the detection of a physiological metabolite of urea molecules. The results reached to a very low concentration of 1mM and exhibited good quantitative character over the physiological concentration range (1∼20mM) under mimicking biophysical conditions. These results show that the prepared substrate has great potential in the ultrasensitive SERS-based detection and in SERS-based biosensors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new type of SERS substrate, consisting of silver nanoparticles and porous gold nanoparticles was fabricated. </LI> <LI> An additional enhancement contribution generated from the porous characteristic of gold nanoparticles. </LI> <LI> The substrates were used for the detection of a physiological metabolite of urea molecules. </LI> <LI> The results exhibited good quantitative character over all the physiological concentration range (1∼20 mM). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fe-N₄ complex embedded free-standing carbon fabric catalysts for higher performance ORR both in alkaline & acidic media

Li, Bing,Sasikala, Suchithra Padmajan,Kim, Dong Ha,Bak, Junu,Kim, Il-Doo,Cho, EunAe,Kim, Sang Ouk Elsevier 2019 Nano energy Vol.56 No.-

<P><B>Abstract</B></P> <P>Pt-based catalysts are suffering from the intrinsic high cost and poor stability for practical use in fuel cells. We develop a free-standing fabric type Pt-free high-performance oxygen reduction reaction (ORR) catalyst, consisting of N, Fe-codoped carbon nanofibers and graphene (N/Fe-CG) hybrids. Electrospinning is used to synthesize the free-standing fabric catalysts. Incorporation of graphene into the nanofiber structure greatly increases the electrical conductivity and catalytic surface area. X-ray photoelectron spectroscopy (XPS) analysis provides evidence that Fe-N<SUB>4</SUB> active centers are possibly formed in the catalyst, as is confirmed by electrochemical tests also. Compared to commercial Pt/C, our N/Fe-CG exhibits a similar level of catalytic activity but superior stability and methanol tolerance in both alkaline and acidic media, making it a good candidate for an ORR electrocatalyst in energy storage/conversion and other relevant applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N, Fe-codoped free-standing carbon fabric ORR catalyst is successfully developed </LI> <LI> The catalyst shows excellent catalytic properties in both alkaline and acidic media </LI> <LI> Sample with N, Fe-codoping reveals better performance than single atom doped samples </LI> <LI> FeN<SUB>4</SUB> complex formation is confirmed by electrochemical performance and XPS analysis </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Phthalocyanines as medicinal photosensitizers: Developments in the last five years

Li, Xingshu,Zheng, Bing-De,Peng, Xiao-Hui,Li, Song-Zi,Ying, Jia-Wen,Zhao, Yuanyuan,Huang, Jian-Dong,Yoon, Juyoung Elsevier 2019 Coordination Chemistry Reviews Vol.379 No.-

<P><B>Abstract</B></P> <P>Owing to their high extinction coefficients, long absorption wavelengths, and modification tunable photophysical and photochemical properties, phthalocyanines (Pcs) have been widely used as photosensitizers for photodynamic therapy (PDT). Advances made in the past five years on the development of Pcs as medicinal photosensitizers are reviewed and the main design considerations for medicinal applications of these substances are discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Recent progresses made in the development of phthalocyanines for photodynamic therapy are outlined. </LI> <LI> Representative water-soluble phthalocyanines are presented. </LI> <LI> Main targeting strategies are discussed. </LI> <LI> Future challenges are also presented. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A reagent-assisted method in SERS detection of methyl salicylate

Li, Yali,Li, Qianwen,Wang, Yanan,Oh, Joohee,Jin, Sila,Park, Yeonju,Zhou, Tieli,Zhao, Bing,Ruan, Weidong,Jung, Young Mee Elsevier 2018 Spectrochimica acta. Part A, Molecular and biomole Vol.195 No.-

<P><B>Abstract</B></P> <P>With the explosive application of methyl salicylate (MS) molecules in food and cosmetics, the further detection of MS molecules becomes particularly important. Here we investigated the detection of MS molecules based on surface-enhanced Raman scattering (SERS) in a novel molecule/assistant/metal system constructed with MS, 4,4′-(hexafluoroisopropylidene) bis (benzoic acid) and Ag nanoparticles (AgNPs). The minimum detection concentration is 10<SUP>−4</SUP> M. To explore the function of assisted reagent, we also referred another system without assistant molecules. The result demonstrates that SERS signals were not acquired, which proves that the assistant molecules are critical for the capture of MS molecules. Two possible mechanisms of MS/assistant/AgNPs system were speculated through two patterns of hydrogen bonds. The linker molecules acted as the role of the bridge between metallic substrates and target molecules through the molecular recognition. This strategy is very beneficial to the expanding of MS detection techniques and other hydrogen bond based coupling detections with SERS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel molecule/assistant/metal system was constructed to achieve the SERS detection of methyl salicylate. </LI> <LI> The intermolecular hydrogen bond was employed as the driving force to accomplish the assembly. </LI> <LI> The obstacle of non-adsorption of target molecules on substrates was solved through the hydrogen-bond-based assembly method. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Identification of native charge-transfer status of p-aminothiolphenol adsorbed on noble metallic substrates by surface-enhanced infrared absorption (SEIRA) spectroscopy

Li, Qianwen,Wang, Yanan,Li, Yali,Park, Yeonju,Chen, Yujing,Wang, Xu,Zhao, Bing,Ruan, Weidong,Jung, Young Mee Elsevier 2018 Spectrochimica acta. Part A, Molecular and biomole Vol.204 No.-

<P><B>Abstract</B></P> <P>p-Aminothiophenol (PATP) is a preferred molecule in research on surface-enhanced Raman scattering (SERS) because of its unique characteristics of high spectral activity, easily induced charge-transfer (CT), and sensitivity to molecular structural changes. However, some aspects are still unclear, such as the initial steady state of PATP on noble metallic substrates without strong additional excitation with incident and/or induced electromagnetic radiation. Information about the initial steady state, especially the intrinsic CT state, is of great importance to elucidate the dynamic processes of CT and/or molecular structural changes under additional excitation. To investigate the native state of an adsorbed molecule, a suitable probe method that does not disrupt the native state of the whole system, including both molecules and substrates, is required. SERS is not applied in this context because of its use of high-energy visible and near-infrared light. Herein, a low-energy probe method, surface-enhanced infrared-absorption (SEIRA) spectroscopy, is employed as a suitable method for studying the native adsorption state of PATP on silver nanoisland films. The molecular structure and adsorption state were investigated. The intrinsic CT state received particular attention by analyzing the CT-related vibration of B<SUB>2</SUB> modes. Using Fourier transform infrared (FTIR), transmission SEIRA and reflection SEIRA spectroscopy, we explained why the relative intensities of some bands were different under different conditions. A quasi-standing orientation of PATP adsorbed on the substrates was also confirmed. More importantly, we demonstrated that there is no perceptible CT between PATP and silver nanoisland films; in contrast, CT generally occurs in a disruptive manner in SERS. Density functional theory (DFT) calculations and the selection rules for infrared (IR) transmission and reflection-absorption spectroscopy were used to analyze the spectra throughout the paper. SEIRA proved to be an effective technique to explore the native adsorption state of molecules without the excessive external disturbance induced by excitation. The results are very important in providing insight into molecules in surface-interface chemistry, enhanced spectroscopy and photoelectronics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The native state of PATP was investigated when adsorbed on silver substrates. </LI> <LI> FTIR and SEIRA allow a probe method with less interference on surfaces. </LI> <LI> The intrinsic charge-transfer state was analyzed through the vibration modes of B<SUB>2</SUB>. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pollen record of the mid- to late-Holocene centennial climate change on the East coast of South Korea and its influential factors

Song, Bing,Yi, Sangheon,Jia, Hongjuan,Nahm, Wook-Hyun,Kim, Jin-Cheul,Lim, Jaesoo,Lee, Jin-Young,Sha, Longbin,Mao, Limi,Yang, Zhongyong,Nakanishi, Toshimichi,Hong, Wan,Li, Zhen Elsevier 2018 Journal of Asian earth sciences Vol.151 No.-

<P><B>Abstract</B></P> <P>To understand historical climate change in western Pacific coastal areas, a sediment core (SOJ-2) from the stable sedimentary environment of the Songjiho Lagoon on the east coast of South Korea was obtained for centennial-resolution palynological analysis. The ages of the SOJ-2 core is well controlled by carbon 14 dating with high-resolution accelerator mass spectrometry (AMS), and the results indicated a general warm to cold climate trend from the mid-Holocene to the present, which can be divided into two different stages: a warmer stage between 6842 and 1297 cal yr BP and a colder stage from 1297 cal yr BP to the present, with fluctuations during these stages. The climate was wetter from 6842 to 6227 cal yr BP and 4520 to 1297 cal yr BP and was drier from 6227 to 4520 cal yr BP. The climate changed to cold and dry during the period from 1297–425 cal yr BP. The impact of human activity on the climate began at approximately 1297 cal yr BP and became pronounced starting in 425 cal yr BP. The general cooling trend may represent a response to decreasing solar insolation; however, the relative dryness or wetness of the climate may have been co-determined by westerlies and the East Asian summer monsoon (EASM). The climate had a teleconnection with the North Atlantic region, resulting from changes in solar activity. Nevertheless, EI Niño–Southern Oscillation (ENSO) activity played an important role in impacting the EASM changes in western Pacific coastal areas.</P> <P><B>Highlights</B></P> <P> <UL> <LI> There is a centennial resolution climate record from 6842 cal yr BP to present. </LI> <LI> The general cooling trend was probably triggered by decreasing solar insolation. </LI> <LI> The precipitation was co-determined by westerlies and the East Asian Summer Monsoon. </LI> <LI> The ENSO activity may be an important factor for East Asian Summer Monsoon change. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly efficient hydrogen evolution catalysis based on MoS₂/CdS/TiO₂ porous composites

Du, Jimin,Wang, Huiming,Yang, Mengke,Zhang, Fangfang,Wu, Haoran,Cheng, Xuechun,Yuan, Sijie,Zhang, Bing,Li, Kaidi,Wang, Yina,Lee, Hyoyoung Elsevier 2018 International journal of hydrogen energy Vol.43 No.19

<P><B>Abstract</B></P> <P>Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H<SUB>2</SUB> fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS<SUB>2</SUB> and pyramid-shaped CdS <I>in-situ</I> co-grown on porous TiO<SUB>2</SUB> photocatalysts (MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB>) are successfully obtained <I>via</I> mild sulfuration of MoO<SUB>3</SUB> and CdO coexisted inside porous TiO<SUB>2</SUB> monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB> composites have average pore size about 500 nm. The 3%MoS<SUB>2</SUB> 10%CdSTiO<SUB>2</SUB> demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H<SUB>2</SUB>-generation rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP> under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS<SUB>2</SUB> facilitates in transporting excited electrons from visible-light on CdS to the porous TiO<SUB>2</SUB> for catalytic hydrogen production, and holes to MoS<SUB>2</SUB> for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MoS<SUB>2</SUB>-CT photocatalysts have been successfully synthesized by two-step method. </LI> <LI> The porous structure can enhance photogenerated electron-hole pairs separation. </LI> <LI> The 3% MoS<SUB>2</SUB>-CT shows an excellent H<SUB>2</SUB> evolution rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Virtual MIMO Communication Strategy Based on Cooperative Groups for Wireless Sensor Networks

Bing Li,Guoqiang Zheng,Na Li,Jishun Li 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.3

As we all know, virtual MIMO technology is an efficient way for energy saving in wireless sensor networks (WSNs). The present virtual MIMO communication strategies in WSNs depend on cluster heads collecting and forwarding source data, which causes big energy consumption. Aiming at this problem, we propose a new virtual-MIMO communication strategy based on cooperative group (CG) in this paper, called Group Collaboration MIMO (GCMIMO). GCMIMO clusters the WSN into several clusters. Each cluster is managed by two cluster heads, master cluster head (MCH) and vice cluster head (VCH). MCH divides the source nodes into several cooperative groups, every two nodes as a group. A CG can constitute a virtual dual-antenna transmitter for sending source data of both nodes directly. VCH and MCH are always seen as a CG, called master cooperative group (MCG), which can receive and forward the data from CGs of other clusters. Unlike the existing virtual MIMO communication strategy, GCMIMO doesn’t require the cluster heads collecting the data of the source nodes, which can reduce the times of source data transmission and improve the energy efficiency. In the simulation, we analyze the energy consumption in each communication phase of GCMIMO. The results indicate that GCMIMO can effectively decrease the energy consumption in data transmission and improve energy efficiency.

Preparation and Characterization of Anti-GP73 Monoclonal Antibodies and Development of Double-antibody Sandwich ELISA

Li, Qi-Wen,Chen, Hong-Bing,Li, Zhi-Yang,Shen, Peng,Qu, Li-Li,Gong, Lai-Ling,Xu, Hong-Pan,Pang, Lu,Si, Jin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.5

Background: Serum Golgi protein 73 (GP73) as a novel and potential marker for diagnosing hepatocellular carcinoma (HCC) have been found to be elevated in HCC patients and associated with clinical variables representing tumor growth and invasiveness. The aim of this study was to prepare a pair of monoclonal antibodys (mAbs) against GP73 and develop a newly designed double-antibody sandwich enzyme-linked immunosorbent assay (s-ELISA), which would be used in the detection of serum GP73 (sGP73) as well as in the diagnosis of HCC. Materials and Methods: Produced by prokaryotic expression, the purified recombinant GP73 (rGP73), produced by prokaryotic expression, was used to immunize the Balb/c mice. Two hybridoma cell lines against GP73 were obtained by fusing mouse Sp2/0 myeloma cells with spleen cells from the immunized mice. The titers of anti-GP73 mAb reached 1:243,000. Western blotting analysis and Immunohistochemistry staining revealed that anti-GP73 mAb could recognize GP73 protein. The double-antibody s-ELISA was successfully established and validated by 119 HCC and 103 normal serum samples. Results: showed that the detection limit of this method could reach 1.56 ng/ml, and sGP73 levels in HCC group (mean=190.6 ng/ml) were much higher than those of in healthy controls (mean=70.92 ng/ml). Conclusions: Results of our study not only showed that sGP73 levels of HCC patients were significantly higher than those of healthy controls, but also indicated that the laboratory homemade anti-GP73 mAbs could be the optimal tool used in evaluating sGP73 levels, which would provide a solid foundation for subsequent clinical applications.

An Ionic Liquid Containing L-Proline Moiety as Highly Efficient and Recyclable Chiral Organocatalyst for Michael Addition

Jiang Li,Xia-Bing Li,Sha Sha Ma,Juan Liu,Ben Hao Li,Bao-Lin Li 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.8

A novel chiral ionic liquid containing proline moiety was synthesized. It can be used as a highly efficient and recyclable chiral organocatalyst for Michael addition of cyclohexanone with (E)-β-nitroalkenes in methanol at room temperature. The Michael addition affords the corresponding products in satisfactory yields of isolated products (78–98%) with high diastereoselectivities and excellent enantioselectivities (up to 98% dr and up to 99% ee). The catalyst can be recycled up to five times without any decrease in yields and stereoselectivities.