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Buledi JA, Amin S, Haider SI, Bhanger MI, Solangi AR. A review on detection of heavy metals from aqueous media using nanomaterial-based sensors. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:58994-59002. [PMID: 32036535 DOI: 10.1007/s11356-020-07865-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
The extensive release of heavy metals into the natural water bodies has become globally prevalent from past few decades. Heavy metal toxicity is becoming a serious threat to human and the environment. Due to their prolonged half-life, potential accumulation in different parts of body, and non-biodegradability, metal ions are being obvious entities that can cause several hazardous health risks. A number of methods have been developed for the detection of heavy/toxic metals based on sensors. Among the various new technologies, chemical and optical nano sensors are emerging technology to detect toxic heavy metals. Several nano sensors have been developed using nano materials, synthesized from green or chemical methods. The nano sensors are convenient to prepare and provide enhanced limit of detection, limit of quantification, and onsite detection. This review covers the recent work reported from 2013 to 2019 for the detection of heavy metals using sensors based on nano materials synthesized by different routes. Graphical abstract.
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Affiliation(s)
- Jamil Ahmed Buledi
- National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan
| | - Sidra Amin
- National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan
| | - Syed Iqleem Haider
- Department of Chemistry, Govt. College University, Hyderabad, Sindh, Pakistan
| | - Muhammad Iqbal Bhanger
- International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Amber R Solangi
- National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan.
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2
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Hwang JH, Fox D, Stanberry J, Anagnostopoulos V, Zhai L, Lee WH. Direct Mercury Detection in Landfill Leachate Using a Novel AuNP-Biopolymer Carbon Screen-Printed Electrode Sensor. MICROMACHINES 2021; 12:649. [PMID: 34205934 PMCID: PMC8229311 DOI: 10.3390/mi12060649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/26/2021] [Accepted: 05/30/2021] [Indexed: 01/06/2023]
Abstract
A novel Au nanoparticle (AuNP)-biopolymer coated carbon screen-printed electrode (SPE) sensor was developed through the co-electrodeposition of Au and chitosan for mercury (Hg) ion detection. This new sensor showed successful Hg2+ detection in landfill leachate using square wave anodic stripping voltammetry (SWASV) with an optimized condition: a deposition potential of -0.6 V, deposition time of 200 s, amplitude of 25 mV, frequency of 60 Hz, and square wave step voltage of 4 mV. A noticeable peak was observed at +0.58 V associated with the stripping current of the Hg ion. The sensor exhibited a good sensitivity of ~0.09 μA/μg (~0.02 μA/nM) and a linear response over the concentration range of 10 to 100 ppb (50-500 nM). The limit of detection (LOD) was 1.69 ppb, which is significantly lower than the safety limit defined by the United States Environmental Protection Agency (USEPA). The sensor had an excellent selective response to Hg2+ in landfill leachate against other interfering cations (e.g., Zn2+, Pb2+, Cd2+, and Cu2+). Fifteen successive measurements with a stable peak current and a lower relative standard deviation (RSD = 5.1%) were recorded continuously using the AuNP-biopolymer-coated carbon SPE sensor, which showed excellent stability, sensitivity and reproducibility and consistent performance in detecting the Hg2+ ion. It also exhibited a good reliability and performance in measuring heavy metals in landfill leachate.
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Affiliation(s)
- Jae-Hoon Hwang
- Department of Civil, Environmental, and Construction Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - David Fox
- NanoScience Technology Center and Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA; (D.F.); (L.Z.)
| | - Jordan Stanberry
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA; (J.S.); (V.A.)
| | | | - Lei Zhai
- NanoScience Technology Center and Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA; (D.F.); (L.Z.)
| | - Woo Hyoung Lee
- Department of Civil, Environmental, and Construction Engineering, University of Central Florida, Orlando, FL 32816, USA
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3
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Sun H, Sun C, Ding X, Lu H, Liu M, Zhao G. In situ monitoring of the selective adsorption mechanism of small environmental pollutant molecules on aptasensor interface by attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123953. [PMID: 33264997 DOI: 10.1016/j.jhazmat.2020.123953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/24/2020] [Accepted: 09/05/2020] [Indexed: 06/12/2023]
Abstract
In situ monitoring of the interactions and properties of pollutant molecules at the aptasensor interface is being a very hot and interesting topic in environmental analysis since its charming molecule level understanding of the mechanism of environmental biosensors. Attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) provides a unique and convenient technique for the in situ analysis, but is not easy for small molecules. Herein, an ATR-SEIRAS platform has been successfully developed to in situ monitor the selective adsorption mechanism of small pollutant molecule atrazine (ATZ) on the aptasensor interface by characteristic N‒H peak of ATZ for the first time. Based on the constructed ATR-SEIRAS platform, a thermodynamics model is established for the selective adsorption of ATZ on the aptasensor interface, described with Langmuir adsorption with a dissociation constant of 1.1 nM. The adsorption kinetics parameters are further obtained with a binding rate constant of 8.08×105 M-1 s-1. A promising and feasible platform has therefore successfully provided for the study of the selective sensing mechanism of small pollutant molecules on biosensors interfaces, further broadening the application of ATR-SEIRAS technology in the field of small pollutant molecules.
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Affiliation(s)
- Huanhuan Sun
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Caiqin Sun
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xue Ding
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Hanxing Lu
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Meichuan Liu
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China.
| | - Guohua Zhao
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, 1239 Siping Road, Shanghai 200092, China.
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4
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Caglayan MO. Mercuric ion detection by plasmon-enhanced spectrophotometric ellipsometer using specific oligonucleotide probes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 241:118682. [PMID: 32650242 DOI: 10.1016/j.saa.2020.118682] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/18/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Pollution due to heavy metal ions, including mercury, has become a major issue because of their toxicities. It is required to monitor mercury levels in aqueous media using fast and selective methods with high accuracy. Ellipsometry is a promising technique for instance when it's combined with the plasmon resonance phenomena. We reported a biosensor system available for qualitative/quantitative determination of mercuric ions in aqueous media where both the spectrophotometric ellipsometry and oligonucleotide recognition elements were used. A single step assay using both a linear (ProbeL) and a hair-pin (ProbeH) type oligonucleotide probe as a recognition element, in addition to a sandwich-type (ProbeLS) assay were developed and compared. The detection limits were 0.23 nM, 0.03 nM and 0.15 pM for ProbeL, ProbeH and ProbeLS, respectively. The detection range was between 0.05 nM and 100 nM Hg2+ for all assays proposed herein.
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Affiliation(s)
- Mustafa Oguzhan Caglayan
- Bilecik Seyh Edebali University, Faculty of Engineering, Bioengineering Department, Bilecik, Turkiye.
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5
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Yin H, Li N, Si Y, Zhang H, Yang B, Wang J. Gold nanonails for surface-enhanced infrared absorption. NANOSCALE HORIZONS 2020; 5:1200-1212. [PMID: 32578657 DOI: 10.1039/d0nh00244e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface-enhanced infrared absorption (SEIRA) can dramatically enhance the vibrational signals of analyte molecules owing to the interaction between plasmons and molecular vibrations. It has huge potential for applications in various detection and diagnostic fields. High-aspect-ratio rod-like metal nanostructures have been the most widely studied nanomaterials for SEIRA. However, nearly all of the rod-like nanostructures reported previously are fabricated using physical methods. They suffer from damping and low areal number densities. In this work, high-aspect-ratio Au nanorods are synthesized, and Au nanonails are prepared through Au overgrowth on the as-prepared Au nanorods. The aspect ratios of the Au nanorods and nanonails can be varied in the range of ∼10 to ∼60, and their longitudinal dipolar plasmon resonance wavelengths can be correspondingly tailored from ∼1.6 to ∼8.3 μm. The Au nanonails exhibit superior SEIRA performance with 4-aminothiophenol used as the probe molecules. They are further used to detect the common biomolecule l-cysteine. Numerical simulations are further performed to understand the experimental results. They match well with the experimental observations, revealing the mechanism of the SEIRA enhancement. Our study demonstrates that colloidal high-aspect-ratio Au nanonails and nanorods can function as SEIRA nanoantennas for highly sensitive molecular detection in various situations.
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Affiliation(s)
- Hang Yin
- Henan Provincial Key Laboratory of Nanocomposites and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006, China.
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6
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A review on nanostructure-based mercury (II) detection and monitoring focusing on aptamer and oligonucleotide biosensors. Talanta 2020; 220:121437. [PMID: 32928439 DOI: 10.1016/j.talanta.2020.121437] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/11/2020] [Accepted: 07/19/2020] [Indexed: 02/08/2023]
Abstract
Heavy metal ion pollution is a severe problem in environmental protection and especially in human health due to their bioaccumulation in organisms. Mercury (II) (Hg2+), even at low concentrations, can lead to DNA damage and give permanent harm to the central nervous system by easily passing through biological membranes. Therefore, sensitive detection and monitoring of Hg2+ is of particular interest with significant specificity. In this review, aptamer-based strategies in combination with nanostructures as well as several other strategies to solve addressed problems in sensor development for Hg2+ are discussed in detail. In particular, the analytical performance of different aptamer and oligonucleotide-based strategies using different signal improvement approaches based on nanoparticles were compared within each strategy and in between. Although quite a number of the suggested methodologies analyzed in this review fulfills the standard requirements, further development is still needed on real sample analysis and analytical performance parameters.
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7
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Murai S, Cabello-Olmo E, Kamakura R, Calvo ME, Lozano G, Atsumi T, Míguez H, Tanaka K. Optical Responses of Localized and Extended Modes in a Mesoporous Layer on Plasmonic Array to Isopropanol Vapor. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:5772-5779. [PMID: 32194885 PMCID: PMC7073950 DOI: 10.1021/acs.jpcc.9b10999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/03/2020] [Indexed: 06/10/2023]
Abstract
Mesoporous silica features open and accessible pores that can intake substances from the outside. The combination of mesoporous silica with plasmonic nanostructures represents an interesting platform for an optical sensor based on the dependence of plasmonic modes on the refractive index of the medium in which metallic nanoparticles are embedded. However, so far only a limited number of plasmonic nanostructures are combined with mesoporous silica, including random dispersion of metallic nanoparticles and flat metallic thin films. In this study, we make a mesoporous silica layer on an aluminum nanocylinder array. Such plasmonic arrangements support both localized surface plasmon resonances (LSPRs) and extended modes which are the result of the hybridization of LSPRs and photonic modes extending into the mesoporous layer. We investigate in situ optical reflectance of this system under controlled pressure of isopropanol vapor. Upon exposure, the capillary condensation in the mesopores results in a gradual spectral shift of the reflectance. Our analysis demonstrates that such shifts depend largely on the nature of the modes; that is, the extended modes show larger shifts compared to localized ones. Our materials represent a useful platform for the field of environmental sensing.
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Affiliation(s)
- Shunsuke Murai
- Department
of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Elena Cabello-Olmo
- Consejo
Superior de Investigaciones Científicas-Universidad de Sevilla, Instituto de Ciencia de Materiales de Sevilla, Calle Américo Vespucio 49, 41092 Sevilla, Spain
| | - Ryosuke Kamakura
- Department
of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Mauricio E. Calvo
- Consejo
Superior de Investigaciones Científicas-Universidad de Sevilla, Instituto de Ciencia de Materiales de Sevilla, Calle Américo Vespucio 49, 41092 Sevilla, Spain
| | - Gabriel Lozano
- Consejo
Superior de Investigaciones Científicas-Universidad de Sevilla, Instituto de Ciencia de Materiales de Sevilla, Calle Américo Vespucio 49, 41092 Sevilla, Spain
| | - Taisuke Atsumi
- Department
of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hernán Míguez
- Consejo
Superior de Investigaciones Científicas-Universidad de Sevilla, Instituto de Ciencia de Materiales de Sevilla, Calle Américo Vespucio 49, 41092 Sevilla, Spain
| | - Katsuhisa Tanaka
- Department
of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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8
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Giordano MC, Tzschoppe M, Barelli M, Vogt J, Huck C, Canepa F, Pucci A, Buatier de Mongeot F. Self-Organized Nanorod Arrays for Large-Area Surface-Enhanced Infrared Absorption. ACS APPLIED MATERIALS & INTERFACES 2020; 12:11155-11162. [PMID: 32049480 DOI: 10.1021/acsami.9b19719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Capabilities of highly sensitive surface-enhanced infrared absorption (SEIRA) spectroscopy are demonstrated by exploiting large-area templates (cm2) based on self-organized (SO) nanorod antennas. We engineered highly dense arrays of gold nanorod antennas featuring polarization-sensitive localized plasmon resonances, tunable over a broadband near- and mid-infrared (IR) spectrum, in overlap with the so-called "functional group" window. We demonstrate polarization-sensitive SEIRA activity, homogeneous over macroscopic areas and stable in time, by exploiting prototype self-assembled monolayers of IR-active octadecanthiol (ODT) molecules. The strong coupling between the plasmonic excitation and molecular stretching modes gives rise to characteristic Fano resonances in SEIRA. The SO engineering of the active hotspots in the arrays allows us to achieve signal amplitude improved up to 5.7%. This figure is competitive to the response of lithographic nanoantennas and is stable when the optical excitation spot varies from the micro- to macroscale, thus enabling highly sensitive SEIRA spectroscopy with cost-effective nanosensor devices.
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Affiliation(s)
- M C Giordano
- Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - M Tzschoppe
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - M Barelli
- Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - J Vogt
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - C Huck
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - F Canepa
- Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - A Pucci
- Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - F Buatier de Mongeot
- Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
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9
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Jeong H, Oh K. Uracil-doped DNA thin solid films: a new way to control optical dispersion of DNA film using a RNA constituent. OPTICS EXPRESS 2019; 27:36075-36087. [PMID: 31873394 DOI: 10.1364/oe.27.036075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
Among five nucleobases, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U), uracil is a key distinctive constituent existing only in ribonucleic acid (RNA). RNA shares the common A, G, and C with deoxyribonucleic acid (DNA) made of A-T, G-C hydrogen bonding. We explored a new attempt to combine uracil (U) with DNA, successfully realizing U-doped DNA thin solid films for the first time. Impacts of uracil on optical properties of the films were thoroughly investigated. The method was based on optimal spin-coating of an aqueous solution of DNA and uracil over silicon or silica substrates. Optical absorption of both aqueous solution and U-doped DNA thin solid films was characterized in a wide spectral range covering UV-visible-IR. Immobilization of uracil within DNA thin solid films was experimentally confirmed by FTIR spectroscopy studies. By using an ellipsometer, we measured the refractive indices of the films and discovered that U-doping was a very effective means to control optical dispersion DNA thin solid film. We further investigated thermo-optic behavior to find impacts of U-doping in DNA films. Detailed thin film processes and optical characterizations are discussed.
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10
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Li J, Yan Z, Li J, Wang Z, Morrison W, Xia XH. Antenna array-enhanced attenuated total reflection IR analysis in an aqueous solution. NANOSCALE 2019; 11:18543-18549. [PMID: 31596296 DOI: 10.1039/c9nr04032c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) is a powerful technique that provides structural and functional information during dynamic reactions in aqueous solutions. One existing limitation is the sensitivity to extract the signals of trace-level analytes from the background water in situ and in real time. Here, we proposed a novel ATR-SEIRAS platform that integrated a large-scale triangle gold antenna array onto a conventional ATR-IR platform to increase the sensitivity of this analytical technique. A square centimeter level well-ordered gold antenna array was fabricated onto an Si prism via nanosphere lithography. The size-dependent antenna array resonance had weak correlation with the incident polarization and antenna orientation, allowing antenna array-enhanced IR detection without the requirement of a microscope. In addition, the antenna resonance shift that occurred due to analyte adsorption-induced refractive index variation could be minimized benefiting from the high refractive index of Si (3.4). As a demonstration, we dynamically monitored the adsorption of the trace levels of proteins on top of the antenna array with a real signal enhancement factor larger than 300. Our platform opens an avenue to apply antenna array-enhanced IR spectroscopy in an aqueous environment measured via commercial IR instruments, which is extremely promising for the interfacial applications that require signal enhancement.
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Affiliation(s)
- Jian Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhendong Yan
- College of Science, Nanjing Forestry University, Nanjing 210037, China
| | - Jin Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhenlin Wang
- School of Physics, Nanjing University, Nanjing, 210093, China
| | - William Morrison
- Molecular Vista Inc., 6840 Via Del Oro, Suite 110, San Jose, CA 95119, USA
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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11
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Pawar S, Teja BR, Nagarjuna R, Ganesan R, Nag A. Probing the surface composition effect of silver-gold alloy in SERS efficiency. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.123638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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12
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Dao TD, Hoang CV, Nishio N, Yamamoto N, Ohi A, Nabatame T, Aono M, Nagao T. Dark-Field Scattering and Local SERS Mapping from Plasmonic Aluminum Bowtie Antenna Array. MICROMACHINES 2019; 10:E468. [PMID: 31337078 PMCID: PMC6680994 DOI: 10.3390/mi10070468] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/07/2019] [Accepted: 07/11/2019] [Indexed: 11/19/2022]
Abstract
On the search for the practical plasmonic materials beyond noble metals, aluminum has been emerging as a favorable candidate as it is abundant and offers the possibility of tailoring the plasmonic resonance spanning from ultra-violet to the infrared range. In this letter, in combination with the numerical electromagnetic simulations, we experimentally study the dark-field scattering spectral mapping of plasmonic resonance from the free-standing Al bowtie antenna arrays and correlate their strong nearfield enhancement with the sensing capability by means of surface-enhanced Raman spectroscopy. The spatial matching of plasmonic and Raman mapping puts another step to realize a very promising application of free-standing Al bowtie antennas for plasmonic sensing.
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Affiliation(s)
- Thang Duy Dao
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Chung Vu Hoang
- Institute of Materials Science (IMS), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet street, Hanoi 100000, Vietnam.
- Institute of Theoretical and Applied Research (ITAR), Duy Tan University, 1 Phung Chi Kien Street, Hanoi 100000, Vietnam.
| | - Natsuki Nishio
- Physics Department, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | - Naoki Yamamoto
- Physics Department, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | - Akihiko Ohi
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Toshihide Nabatame
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Masakazu Aono
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Tadaaki Nagao
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.
- Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Kita-10 Nishi-8 Kita-ku, Sapporo 060-0810, Japan.
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13
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Santangelo MF, Shtepliuk I, Filippini D, Puglisi D, Vagin M, Yakimova R, Eriksson J. Epitaxial Graphene Sensors Combined with 3D-Printed Microfluidic Chip for Heavy Metals Detection. SENSORS 2019; 19:s19102393. [PMID: 31130608 PMCID: PMC6567039 DOI: 10.3390/s19102393] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/13/2019] [Accepted: 05/22/2019] [Indexed: 01/17/2023]
Abstract
In this work, we investigated the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb and Cd), showing fast and stable response and low detection limit. The sensing platform proposed includes 3D-printed microfluidic devices, which incorporate all features required to connect and execute lab-on-chip (LOC) functions. The obtained results indicate that EG exhibits excellent sensing activity towards Pb and Cd ions. Several concentrations of Pb2+ solutions, ranging from 125 nM to 500 µM, were analyzed showing Langmuir correlation between signal and Pb2+ concentrations, good stability, and reproducibility over time. Upon the simultaneous presence of both metals, sensor response is dominated by Pb2+ rather than Cd2+ ions. To explain the sensing mechanisms and difference in adsorption behavior of Pb2+ and Cd2+ ions on EG in water-based solutions, we performed van-der-Waals (vdW)-corrected density functional theory (DFT) calculations and non-covalent interaction (NCI) analysis, extended charge decomposition analysis (ECDA), and topological analysis. We demonstrated that Pb2+ and Cd2+ ions act as electron-acceptors, enhancing hole conductivity of EG, due to charge transfer from graphene to metal ions, and Pb2+ ions have preferential ability to binding with graphene over cadmium. Electrochemical measurements confirmed the conductometric results, which additionally indicate that EG is more sensitive to lead than to cadmium.
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Affiliation(s)
- Maria Francesca Santangelo
- Applied Sensors Science, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
| | - Ivan Shtepliuk
- Semiconductor Materials, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
| | - Daniel Filippini
- Optical Devices Laboratory, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
| | - Donatella Puglisi
- Applied Sensors Science, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
| | - Mikhail Vagin
- Division of Physics and Electronics, Department of Science and Technology, Physics and Electronics-ITN, Linköping University, SE-58183 Linköping, Sweden.
| | - Rositsa Yakimova
- Semiconductor Materials, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
| | - Jens Eriksson
- Applied Sensors Science, Department of Physics, Chemistry, and Biology-IFM, Linköping University, S-58183 Linköping, Sweden.
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14
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Dao TD, Chen K, Nagao T. Dual-band in situ molecular spectroscopy using single-sized Al-disk perfect absorbers. NANOSCALE 2019; 11:9508-9517. [PMID: 31049510 DOI: 10.1039/c9nr00904c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We propose antenna-enhanced infrared vibrational spectroscopy by adopting single-sized Al disks on Al2O3-Al films fabricated by colloidal-mask lithography. The precisely designed plasmonic resonator with dual-band perfect absorption (DPA) shows strongly-enhanced nearfield intensity and polarization independence, at both resonances, providing a powerful antenna platform for the multi-band vibrational sensing. As a proof of concept, we experimentally apply the plasmonic DPAs in bond-selective dual-band infrared sensing of an ultrathin polydimethylsiloxane (PDMS) film, simultaneously amplifying two representative vibrational bands (asymmetric C-H stretching of CH3 at 2962 cm-1 and CH3 deformation of Si-CH3 at 1263 cm-1) by surface-enhanced infrared absorption spectroscopy (SEIRA). The plasmonic DPA was successfully adopted for the in situ monitoring of reaction kinetics, by recording the spectral changes in C-H stretching and Si-CH3 deformation modes of a 10 nm PDMS elastomer, which are selectively enhanced by the two antenna resonances, during its gelation process. Our systematic study of the SEIRA spectra has demonstrated mode splitting and a clear avoided-crossing in the dispersion curve as a function of resonance frequency of DPA, manifesting itself as a promising basis for future polaritonic devices utilizing the hybridization between the molecular vibrational states and the enhanced light field.
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Affiliation(s)
- Thang Duy Dao
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
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15
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Li Z, Zhang Z, Chen K. Indium⁻Tin⁻Oxide Nanostructures for Plasmon-Enhanced Infrared Spectroscopy: A Numerical Study. MICROMACHINES 2019; 10:mi10040241. [PMID: 30979000 PMCID: PMC6523928 DOI: 10.3390/mi10040241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/28/2019] [Accepted: 04/03/2019] [Indexed: 01/24/2023]
Abstract
Plasmonic nanoantennas can significantly enhance the light–matter interactions at the nanoscale, and as a result have been used in a variety of applications such as sensing molecular vibrations in the infrared range. Indium–tin–oxide (ITO) shows metallic behavior in the infrared range, and can be used for alternative plasmonic materials. In this work, we numerically studied the optical properties of hexagonal ITO nanodisk and nanohole arrays in the mid-infrared. Field enhancement up to 10 times is observed in the simulated ITO nanostructures. Furthermore, we demonstrated the sensing of the surface phonon polariton from a 2-nm thick SiO2 layer under the ITO disk arrays. Such periodic arrays can be readily fabricated by colloidal lithography and dry etching techniques; thus, the results shown here can help design efficient ITO nanostructures for plasmonic infrared applications.
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Affiliation(s)
- Zhangbo Li
- Institute of Photonics Technology, Jinan University, Guangzhou 511443, China.
| | - Zhiliang Zhang
- Institute of Photonics Technology, Jinan University, Guangzhou 511443, China.
| | - Kai Chen
- Institute of Photonics Technology, Jinan University, Guangzhou 511443, China.
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16
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Gu YQ, Shen WY, Mi Y, Jing YF, Yuan JM, Yu P, Zhu XM, Hu FL. Dual-response detection of Ni2+ and Cu2+ ions by a pyrazolopyrimidine-based fluorescent sensor and the application of this sensor in bioimaging. RSC Adv 2019; 9:35671-35676. [PMID: 35528093 PMCID: PMC9074711 DOI: 10.1039/c9ra06227k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/16/2019] [Indexed: 11/21/2022] Open
Abstract
Herein, a dual-response fluorescent sensor, L, based on pyrazolopyrimidine was designed and developed for the simultaneous detection of Ni2+ and Cu2+ ions in the presence of other metal ions; the structural characterization of L was carried out by FTIR spectroscopy, NMR spectroscopy, HRMS and X-ray diffraction analysis. The sensor L effectively displayed fluorescence quenching towards the Ni2+ and Cu2+ ions with high sensitivity without interference from other metal ions. The results reveal that L binds to Ni2+ and Cu2+ in a 2 : 1 pattern, which matches well with the result of the Job's plot. The association constants of L with Ni2+ and Cu2+ were 3.2 × 104 M−1 and 7.57 × 104 M−1, respectively. The detection limits (DLs) are down to 8.9 nM for Ni2+ and 8.7 nM for Cu2+. The fluorescence imaging of L in T-24 cells was investigated because of the low cytotoxicity of L, indicating that L could be used to detect Ni2+ and Cu2+ in living cells. A pyrazolopyrimidine-based fluorescent sensor L was developed and applied for detection of Cu2+ and Ni2+ in ethanol solution by photoluminescence quenching. It shows low cytotoxicity and good imaging characteristics for Cu2+ and Ni2+ in living cells.![]()
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Affiliation(s)
- Yun-Qiong Gu
- School of Environment and Life Science
- Nanning Normal University
- Nanning
- China
- Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University)
| | - Wen-Ying Shen
- Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University)
- Ministry of Education of China
- China
| | - Yan Mi
- Guangxi Key Laboratory of Chemistry and Engineering of Forest Products
- Guangxi University for Nationalities
- Nanning
- China
| | - Yan-Fang Jing
- Guangxi Key Laboratory of Chemistry and Engineering of Forest Products
- Guangxi University for Nationalities
- Nanning
- China
| | - Jing-Mei Yuan
- Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University)
- Ministry of Education of China
- China
| | - Peng Yu
- School of Environment and Life Science
- Nanning Normal University
- Nanning
- China
| | - Xiao-Min Zhu
- Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University)
- Ministry of Education of China
- China
| | - Fei-Long Hu
- Guangxi Key Laboratory of Chemistry and Engineering of Forest Products
- Guangxi University for Nationalities
- Nanning
- China
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17
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Law CS, Lim SY, Abell AD, Santos A. Real-Time Binding Monitoring between Human Blood Proteins and Heavy Metal Ions in Nanoporous Anodic Alumina Photonic Crystals. Anal Chem 2018; 90:10039-10048. [PMID: 30041521 DOI: 10.1021/acs.analchem.8b02732] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study reports on the real-time binding assessment between heavy metal ions and blood proteins immobilized onto nanoporous anodic alumina photonic crystals (NAA-PCs) by reflectometric interference spectroscopy (RIfS). The surface of NAA-PCs is chemically functionalized with γ-globulin (GG), transferrin (TFN), and serum albumin (HSA), the major proteins present in human blood plasma. Protein-modified NAA-PC platforms are exposed to analytical solutions of mercury ions of different concentrations. Dynamic changes in the effective optical thickness of protein-modified NAA-PCs in response to heavy metal ions are assessed in real time to evaluate the binding kinetics, affinity, and mechanism. Protein molecules undergo conformational changes upon exposure to mercury ions, with HSA exhibiting the strongest affinity. The combination of protein-modified NAA-PCs with RIfS allows real-time monitoring of protein-heavy metal ions interactions under dynamic flow conditions. This system is capable of detecting dynamic conformational changes in these proteins upon exposure to heavy metal ions. Our results provide new insights into these binding events, which could enable new methodologies to study the toxicity of heavy metal ions and other biomolecular interactions.
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Affiliation(s)
- Cheryl Suwen Law
- School of Chemical Engineering , The University of Adelaide , 5005 Adelaide , Australia.,Institute for Photonics and Advanced Sensing (IPAS) , The University of Adelaide , 5005 Adelaide , Australia.,ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) , The University of Adelaide , 5005 Adelaide , Australia
| | - Siew Yee Lim
- School of Chemical Engineering , The University of Adelaide , 5005 Adelaide , Australia.,Institute for Photonics and Advanced Sensing (IPAS) , The University of Adelaide , 5005 Adelaide , Australia.,ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) , The University of Adelaide , 5005 Adelaide , Australia
| | - Andrew D Abell
- Institute for Photonics and Advanced Sensing (IPAS) , The University of Adelaide , 5005 Adelaide , Australia.,ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) , The University of Adelaide , 5005 Adelaide , Australia.,Department of Chemistry , The University of Adelaide , 5005 Adelaide , Australia
| | - Abel Santos
- School of Chemical Engineering , The University of Adelaide , 5005 Adelaide , Australia.,Institute for Photonics and Advanced Sensing (IPAS) , The University of Adelaide , 5005 Adelaide , Australia.,ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) , The University of Adelaide , 5005 Adelaide , Australia
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18
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Guo PF, Zhang DD, Guo ZY, Wang XM, Wang MM, Chen ML, Wang JH. PEGylated titanate nanosheets: hydrophilic monolayers with a superior capacity for the selective isolation of immunoglobulin G. NANOSCALE 2018; 10:12535-12542. [PMID: 29931026 DOI: 10.1039/c8nr02995d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A novel organic-inorganic hybrid was prepared by anchoring (3-aminopropyl)triethoxysilane (APTES) on the surface of monolayer titanate nanosheets and subsequent modification with hydrophilic polyethylene glycol (PEG). The PEGylated hydrophilic monolayer titanate nanosheets were abbreviated as PEG-APTES-TiNSs, and they exhibit a lateral dimension of dozens of nanometers and a thickness of ca. 1.9 nm. PEGylation of the titanate nanosheets significantly improved their selectivity toward the adsorption of glycoproteins through strong hydrophilic interaction, providing an adsorption capacity of 2540.9 mg g-1 for immunoglobulin G (IgG). The retained IgG is readily collected at a recovery rate of 83.4% with 0.5% (m/v) ammonium hydroxide (NH4OH) as the stripping reagent. PEG-APTES-TiNSs are applied for the selective adsorption of IgG from human serum, which is further confirmed by SDS-PAGE assay.
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Affiliation(s)
- Peng-Fei Guo
- Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China.
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19
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Ullah N, Mansha M, Khan I, Qurashi A. Nanomaterial-based optical chemical sensors for the detection of heavy metals in water: Recent advances and challenges. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.01.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Bao WJ, Li J, Li J, Zhang QW, Liu Y, Shi CF, Xia XH. Au/ZnSe-Based Surface Enhanced Infrared Absorption Spectroscopy as a Universal Platform for Bioanalysis. Anal Chem 2018; 90:3842-3848. [DOI: 10.1021/acs.analchem.7b04505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Wen-Jing Bao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Jian Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Jin Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Qian-Wen Zhang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Yang Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Cai-Feng Shi
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
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21
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Singha NR, Dutta A, Mahapatra M, Karmakar M, Mondal H, Chattopadhyay PK, Maiti DK. Guar Gum-Grafted Terpolymer Hydrogels for Ligand-Selective Individual and Synergistic Adsorption: Effect of Comonomer Composition. ACS OMEGA 2018; 3:472-494. [PMID: 31457906 PMCID: PMC6641655 DOI: 10.1021/acsomega.7b01682] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/27/2017] [Indexed: 05/20/2023]
Abstract
Grafting of guar gum (GG) and in situ strategic attachment of acrylamidosodiumpropanoate (ASP) via solution polymerization of acrylamide (AM) and sodium acrylate (SA) resulted in the synthesis of a sustainable GG-g-(AM-co-SA-co-ASP)/GGAMSAASP interpenetrating polymer network (IPN)-based smart superadsorbent with excellent physicochemical properties and reusability, through systematic optimization by response surface methodology (RSM) for removal of methyl violet (MV) and/or Hg(II). The relative effects of SA/AM ratios, in situ allocation of ASP, grafting of GG into the AMSAASP terpolymer, ligand-selective superadsorption mechanism, and relative microstructural changes in individually/synergistically-adsorbed MV-/Hg(II)-/Hg(II)-MV-GGAMSAASPs were determined by extensive analyses using Fourier transform infrared (FTIR), proton nuclear magnetic resonance, ultraviolet-visible (UV-vis), and O 1s-/N 1s-/C 1s-/Hg 4f7/2,5/2-X-ray photoelectron spectroscopies, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, field emission scanning electron microscopy, and energy-dispersive spectroscopy and were supported by % gel content, pHPZC, and % graft ratio. The ionic/covalent-bonding, monodentate, bidentate bridging, and bidentate chelating coordination between GGAMSAASPs and Hg(II), and MV+-Hg(II) bonding were rationalized by FTIR, UV-vis, fitment of kinetics data to the pseudo-second-order model, and thermodynamic parameters. The maximum adsorption capacities of 49.12 and 53.28 mg g-1 were determined for Hg(II) and MV, respectively, under optimized conditions.
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Affiliation(s)
- Nayan Ranjan Singha
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Arnab Dutta
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Manas Mahapatra
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Mrinmoy Karmakar
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Himarati Mondal
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Pijush Kanti Chattopadhyay
- Advanced
Polymer Laboratory, Department of Polymer Science and Technology, and Department of
Leather Technology, Government College of
Engineering and Leather Technology (Post-Graduate), Maulana
Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India
| | - Dilip K. Maiti
- Department
of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
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22
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Nien LW, Chen K, Dao TD, Ishii S, Hsueh CH, Nagao T. Far-field and near-field monitoring of hybridized optical modes from Au nanoprisms suspended on a graphene/Si nanopillar array. NANOSCALE 2017; 9:16950-16959. [PMID: 29077124 DOI: 10.1039/c7nr05988d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The optical hybridization of localized surface plasmons and photonic modes of dielectric nanostructures provides us wide arenas of opportunities for designing tunable nanophotonics with excellent spectral selectivity, signal enhancement, and light harvesting for many optical applications. Graphene-supported Au nanoprisms on a periodic Si nanopillar array will be an ideal model system for examining such an optical hybridization effect between plasmonic modes and photonic modes. Here, through the measurement of the reflectance spectra as well as graphene phonons by surface-enhanced Raman scattering (SERS), we investigated both the far-field and near-field properties of these optically hybridized modes. The effects of photonic modes and Mie resonances of the Si nanopillars on the localized surface plasmons of the Au nanoprisms and on their near-field enhancement were experimentally elucidated through the measurements of graphene phonons using two excitation lasers with wavelengths of 532 and 785 nm. The wavelength-dependent SERS intensities of monolayer graphene are clearly understood in terms of the optical hybridization, and the SERS enhancement factor estimated from finite-difference time-domain simulations exhibited good agreement with the measurements. The elucidated spectral tunability in the near-field light-matter interaction would be useful for potential applications in various types of graphene-based photonics.
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Affiliation(s)
- Li-Wei Nien
- Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan.
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23
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Kraack JP, Frei A, Alberto R, Hamm P. Ultrafast Vibrational Energy Transfer in Catalytic Monolayers at Solid-Liquid Interfaces. J Phys Chem Lett 2017; 8:2489-2495. [PMID: 28521090 DOI: 10.1021/acs.jpclett.7b01034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigate the ultrafast vibrational dynamics of monolayers from adsorbed rhenium-carbonyl CO2-reduction catalysts on a semiconductor surface (indium-tin-oxide (ITO)) with ultrafast two-dimensional attenuated total reflection infrared (2D ATR IR) spectroscopy. The complexes are partially equipped with isotope-labeled (13C) carbonyl ligands to generate two spectroscopically distinguishable forms of the molecules. Ultrafast vibrational energy transfer between the molecules is observed via the temporal evolution of cross-peaks between their symmetric carbonyl stretching vibrations. These contributions appear with time constant of 70 and 90 ps for downhill and uphill energy transfer, respectively. The energy transfer is thus markedly slower than any of the other intramolecular dynamics. From the transfer rate, an intermolecular distance of ∼4-5 Å can be estimated, close to the van der Waals distance of the molecular head groups. The present paper presents an important cornerstone for a better understanding of intermolecular coupling mechanisms of molecules on surfaces and explains the absence of similar features in earlier studies.
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Affiliation(s)
- Jan Philip Kraack
- Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Angelo Frei
- Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Roger Alberto
- Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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24
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Kühner L, Hentschel M, Zschieschang U, Klauk H, Vogt J, Huck C, Giessen H, Neubrech F. Nanoantenna-Enhanced Infrared Spectroscopic Chemical Imaging. ACS Sens 2017; 2:655-662. [PMID: 28723169 DOI: 10.1021/acssensors.7b00063] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spectroscopic infrared chemical imaging is ideally suited for label-free and spatially resolved characterization of molecular species, but often suffers from low infrared absorption cross sections. Here, we overcome this limitation by utilizing confined electromagnetic near-fields of resonantly excited plasmonic nanoantennas, which enhance the molecular absorption by orders of magnitude. In the experiments, we evaporate microstructured chemical patterns of C60 and pentacene with nanometer thickness on top of homogeneous arrays of tailored nanoantennas. Broadband mid-infrared spectra containing plasmonic and vibrational information were acquired with diffraction-limited resolution using a two-dimensional focal plane array detector. Evaluating the enhanced infrared absorption at the respective frequencies, spatially resolved chemical images were obtained. In these chemical images, the microstructured chemical patterns are only visible if nanoantennas are used. This confirms the superior performance of our approach over conventional spectroscopic infrared imaging. In addition to the improved sensitivity, our technique provides chemical selectivity, which would not be available with plasmonic imaging that is based on refractive index sensing. To extend the accessible spectral bandwidth of nanoantenna-enhanced spectroscopic imaging, we employed nanostructures with dual-band resonances, providing broadband plasmonic enhancement and sensitivity. Our results demonstrate the potential of nanoantenna-enhanced spectroscopic infrared chemical imaging for spatially resolved characterization of organic layers with thicknesses of several nanometers. This is of potential interest for medical applications which are currently hampered by state-of-art infrared techniques, e.g., for distinguishing cancerous from healthy tissues.
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Affiliation(s)
- Lucca Kühner
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Mario Hentschel
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Ute Zschieschang
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Hagen Klauk
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Jochen Vogt
- Kirchhoff
Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Christian Huck
- Kirchhoff
Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Harald Giessen
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Frank Neubrech
- 4th
Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Kirchhoff
Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
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25
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Zeptomolar detection of Hg 2+ based on label-free electrochemical aptasensor: One step closer to the dream of single atom detection. Electrochem commun 2017. [DOI: 10.1016/j.elecom.2017.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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26
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Neubrech F, Huck C, Weber K, Pucci A, Giessen H. Surface-Enhanced Infrared Spectroscopy Using Resonant Nanoantennas. Chem Rev 2017; 117:5110-5145. [PMID: 28358482 DOI: 10.1021/acs.chemrev.6b00743] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infrared spectroscopy is a powerful tool widely used in research and industry for a label-free and unambiguous identification of molecular species. Inconveniently, its application to spectroscopic analysis of minute amounts of materials, for example, in sensing applications, is hampered by the low infrared absorption cross-sections. Surface-enhanced infrared spectroscopy using resonant metal nanoantennas, or short "resonant SEIRA", overcomes this limitation. Resonantly excited, such metal nanostructures feature collective oscillations of electrons (plasmons), providing huge electromagnetic fields on the nanometer scale. Infrared vibrations of molecules located in these fields are enhanced by orders of magnitude enabling a spectroscopic characterization with unprecedented sensitivity. In this Review, we introduce the concept of resonant SEIRA and discuss the underlying physics, particularly, the resonant coupling between molecular and antenna excitations as well as the spatial extent of the enhancement and its scaling with frequency. On the basis of these fundamentals, different routes to maximize the SEIRA enhancement are reviewed including the choice of nanostructures geometries, arrangements, and materials. Furthermore, first applications such as the detection of proteins, the monitoring of dynamic processes, and hyperspectral infrared chemical imaging are discussed, demonstrating the sensitivity and broad applicability of resonant SEIRA.
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Affiliation(s)
- Frank Neubrech
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart , Pfaffenwaldring 57, Stuttgart 70569, Germany.,Kirchhoff Institute for Physics, Heidelberg University , Im Neuenheimer Feld 227, Heidelberg 69120, Germany
| | - Christian Huck
- Kirchhoff Institute for Physics, Heidelberg University , Im Neuenheimer Feld 227, Heidelberg 69120, Germany
| | - Ksenia Weber
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart , Pfaffenwaldring 57, Stuttgart 70569, Germany
| | - Annemarie Pucci
- Kirchhoff Institute for Physics, Heidelberg University , Im Neuenheimer Feld 227, Heidelberg 69120, Germany
| | - Harald Giessen
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart , Pfaffenwaldring 57, Stuttgart 70569, Germany
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27
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Chen K, Duy Dao T, Nagao T. Tunable Nanoantennas for Surface Enhanced Infrared Absorption Spectroscopy by Colloidal Lithography and Post-Fabrication Etching. Sci Rep 2017; 7:44069. [PMID: 28272442 PMCID: PMC5341049 DOI: 10.1038/srep44069] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/03/2017] [Indexed: 01/03/2023] Open
Abstract
We fabricated large-area metallic (Al and Au) nanoantenna arrays on Si substrates using cost-effective colloidal lithography with different micrometer-sized polystyrene spheres. Variation of the sphere size leads to tunable plasmon resonances in the middle infrared (MIR) range. The enhanced near-fields allow us to detect the surface phonon polaritons in the natural SiO2 thin layers. We demonstrated further tuning capability of the resonances by employing dry etching of the Si substrates with the nanoantennas acting as the etching masks. The effective refractive index of the nanoantenna surroundings is efficiently decreased giving rise to blueshifts of the resonances. In addition, partial removal of the Si substrates elevates the nanoantennas from the high-refractive-index substrates making more enhanced near-fields accessible for molecular sensing applications as demonstrated here with surface-enhanced infrared absorption (SEIRA) spectroscopy for a thin polymer film. We also directly compared the plasmonic enhancement from the Al and Au nanoantenna arrays.
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Affiliation(s)
- Kai Chen
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Thang Duy Dao
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Tadaaki Nagao
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
- Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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Attenuated Total Reflection Surface-Enhanced Infrared Absorption Spectroscopy: a Powerful Technique for Bioanalysis. JOURNAL OF ANALYSIS AND TESTING 2017. [DOI: 10.1007/s41664-017-0009-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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29
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Kraack JP, Hamm P. Surface-Sensitive and Surface-Specific Ultrafast Two-Dimensional Vibrational Spectroscopy. Chem Rev 2016; 117:10623-10664. [DOI: 10.1021/acs.chemrev.6b00437] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jan Philip Kraack
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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30
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Bui TS, Dao TD, Dang LH, Vu LD, Ohi A, Nabatame T, Lee Y, Nagao T, Hoang CV. Metamaterial-enhanced vibrational absorption spectroscopy for the detection of protein molecules. Sci Rep 2016; 6:32123. [PMID: 27555217 PMCID: PMC4995369 DOI: 10.1038/srep32123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/02/2016] [Indexed: 11/10/2022] Open
Abstract
From visible to mid-infrared frequencies, molecular sensing has been a major successful application of plasmonics because of the enormous enhancement of the surface electromagnetic nearfield associated with the induced collective motion of surface free carriers excited by the probe light. However, in the lower-energy terahertz (THz) region, sensing by detecting molecular vibrations is still challenging because of low sensitivity, complicated spectral features, and relatively little accumulated knowledge of molecules. Here, we report the use of a micron-scale thin-slab metamaterial (MM) architecture, which functions as an amplifier for enhancing the absorption signal of the THz vibration of an ultrathin adsorbed layer of large organic molecules. We examined bovine serum albumin (BSA) as a prototype large protein molecule and Rhodamine 6G (Rh6G) and 3,3'-diethylthiatricarbocyanine iodide (DTTCI) as examples of small molecules. Among them, our MM significantly magnified only the signal strength of bulky BSA. On the other hand, DTTCI and Rh6G are inactive, as they lack low-frequency vibrational modes in this frequency region. The results obtained here clearly demonstrate the promise of MM-enhanced absorption spectroscopy in the THz region for detection and structural monitoring of large biomolecules such as proteins or pathogenic enzymes.
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Affiliation(s)
- Tung S Bui
- Institute of Materials Science (IMS), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi, Vietnam.,Quantum Photonic Science Research Center, Department of Physics, Hanyang University, Seoul 133-791, Korea
| | - Thang D Dao
- International Center for Materials NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.,CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Luu H Dang
- Institute of Materials Science (IMS), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi, Vietnam
| | - Lam D Vu
- Institute of Materials Science (IMS), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi, Vietnam
| | - Akihiko Ohi
- International Center for Materials NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Toshihide Nabatame
- International Center for Materials NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - YoungPak Lee
- Quantum Photonic Science Research Center, Department of Physics, Hanyang University, Seoul 133-791, Korea
| | - Tadaaki Nagao
- International Center for Materials NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan.,CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.,Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Kita-10 Nishi-8 Kita-ku, Sapporo 060-0810, Japan
| | - Chung V Hoang
- Institute of Materials Science (IMS), Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay District, Hanoi, Vietnam
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31
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Braun A, Maier SA. Versatile Direct Laser Writing Lithography Technique for Surface Enhanced Infrared Spectroscopy Sensors. ACS Sens 2016. [DOI: 10.1021/acssensors.6b00469] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Avi Braun
- Blackett Laboratory, Department
of Physics, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stefan Alexander Maier
- Blackett Laboratory, Department
of Physics, Imperial College London, London SW7 2AZ, United Kingdom
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32
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Mao S, Chang J, Zhou G, Chen J. Nanomaterial-enabled Rapid Detection of Water Contaminants. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:5336-59. [PMID: 26315216 DOI: 10.1002/smll.201500831] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/24/2015] [Indexed: 05/18/2023]
Abstract
Water contaminants, e.g., inorganic chemicals and microorganisms, are critical metrics for water quality monitoring and have significant impacts on human health and plants/organisms living in water. The scope and focus of this review is nanomaterial-based optical, electronic, and electrochemical sensors for rapid detection of water contaminants, e.g., heavy metals, anions, and bacteria. These contaminants are commonly found in different water systems. The importance of water quality monitoring and control demands significant advancement in the detection of contaminants in water because current sensing technologies for water contaminants have limitations. The advantages of nanomaterial-based sensing technologies are highlighted and recent progress on nanomaterial-based sensors for rapid water contaminant detection is discussed. An outlook for future research into this rapidly growing field is also provided.
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Affiliation(s)
- Shun Mao
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin, 53211, USA
| | - Jingbo Chang
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin, 53211, USA
| | - Guihua Zhou
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin, 53211, USA
| | - Junhong Chen
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin, 53211, USA
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33
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Zheng P, Li M, Jurevic R, Cushing SK, Liu Y, Wu N. A gold nanohole array based surface-enhanced Raman scattering biosensor for detection of silver(I) and mercury(II) in human saliva. NANOSCALE 2015; 7:11005-12. [PMID: 26008641 PMCID: PMC4476066 DOI: 10.1039/c5nr02142a] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A surface-enhanced Raman scattering (SERS) biosensor has been developed by incorporating a gold nanohole array with a SERS probe (a gold nanostar@Raman-reporter@silica sandwich structure) into a single detection platform via DNA hybridization, which circumvents the nanoparticle aggregation and the inefficient Raman scattering issues. Strong plasmonic coupling between the Au nanostar and the Au nanohole array results in a large enhancement of the electromagnetic field, leading to amplification of the SERS signal. The SERS sensor has been used to detect Ag(I) and Hg(II) ions in human saliva because both the metal ions could be released from dental amalgam fillings. The developed SERS sensor can be adapted as a general detection platform for non-invasive measurements of a wide range of analytes such as metal ions, small molecules, DNA and proteins in body fluids.
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Affiliation(s)
- Peng Zheng
- Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, USA.
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34
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Zhang Y, Xie J, Liu Y, Pang P, Feng L, Wang H, Wu Z, Yang W. Simple and signal-off electrochemical biosensor for mercury(II) based on thymine-mercury-thymine hybridization directly on graphene. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.04.152] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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35
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Senthamizhan A, Celebioglu A, Uyar T. Real-time selective visual monitoring of Hg(2+) detection at ppt level: An approach to lighting electrospun nanofibers using gold nanoclusters. Sci Rep 2015; 5:10403. [PMID: 26020609 PMCID: PMC4446990 DOI: 10.1038/srep10403] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
In this work, fluorescent gold nanocluster (AuNC) decorated polycaprolactone (PCL) nanofibers (AuNC*PCL-NF) for real time visual monitoring of Hg(2+) detection at ppt level in water is demonstrated. The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time. The fluorescence changes of AuNC*PCL-NF and their corresponding time dependent spectra, upon introduction of Hg(2+), led to the visual identification of the sensor performance. It is observed that the effective removal of excess ligand (bovine serum albumin (BSA) greatly enhances the surface exposure of AuNC and therefore their selective sensing performance is achieved over competent metal ions such as Cu(2+), Ni(2+), Mn(2+), Zn(2+), Cd(2+), and Pb(2+) present in the water. An exceptional interaction is observed between AuNC and Hg(2+), wherein the absence of excess interrupting ligand makes AuNC more selective towards Hg(2+). The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies. In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.
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Affiliation(s)
- Anitha Senthamizhan
- UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey
| | - Asli Celebioglu
- 1] UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey [2] Institute of Materials Science &Nanotechnology, Bilkent University, Ankara, 06800, Turkey
| | - Tamer Uyar
- 1] UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey [2] Institute of Materials Science &Nanotechnology, Bilkent University, Ankara, 06800, Turkey
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36
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Yoshioka K, Minami Y, Shudo KI, Dao TD, Nagao T, Kitajima M, Takeda J, Katayama I. Terahertz-field-induced nonlinear electron delocalization in Au nanostructures. NANO LETTERS 2015; 15:1036-1040. [PMID: 25559640 DOI: 10.1021/nl503916t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Improved control over the electromagnetic properties of metal nanostructures is indispensable for the development of next-generation integrated nanocircuits and plasmonic devices. The use of terahertz (THz)-field-induced nonlinearity is a promising approach to controlling local electromagnetic properties. Here, we demonstrate how intense THz electric fields can be used to modulate electron delocalization in percolated gold (Au) nanostructures on a picosecond time scale. We prepared both isolated and percolated Au nanostructures deposited on high resistivity Si(100) substrates. With increasing the applied THz electric fields, large opacity in the THz transmission spectra takes place in the percolated nanostructures; the maximum THz-field-induced transmittance difference, 50% more, is reached just above the percolation threshold thickness. Fitting the experimental data to a Drude-Smith model, we found furthermore that the localization parameter and the damping constant strongly depend on the applied THz-field strength. These results show that ultrafast nonlinear electron delocalization proceeds via strong electric field of THz pulses; the intense THz electric field modulates the backscattering rate of localized electrons and induces electron tunneling between Au nanostructures across the narrow insulating bridges without any material breakdown.
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Affiliation(s)
- Katsumasa Yoshioka
- Department of Physics, Graduate School of Engineering, Yokohama National University , Yokohama 240-8501, Japan
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37
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Liu M, Wang Z, Pan L, Cui Y, Liu Y. A SERS/fluorescence dual-mode nanosensor based on the human telomeric G-quadruplex DNA: Application to mercury (II) detection. Biosens Bioelectron 2015; 69:142-7. [PMID: 25725462 DOI: 10.1016/j.bios.2015.02.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/24/2015] [Accepted: 02/06/2015] [Indexed: 11/17/2022]
Abstract
DNA-metal nanoparticle conjugates have been increasingly exploited for sensing purposes over the past decades. However, most of the existing strategies are operated with canonical DNA structures, such as single-stranded forms, stem-loop structures, and double helix structures. There is intense interest in the development of nano-system based on high order DNA secondary structures. Herein, we propose a SERS/fluorescence dual-mode nanosensor, where the signal transduction mechanism is based on the conformational switching of the human telomeric G-quadruplex DNA. The nanosensor exhibits excellent SERS/fluorescence responses to the complementary strands of G-quadruplexes. Based on T-Hg(2+)-T coordination chemistry, this sensor is effectively applied to determination of Hg(2+) in buffer solution and real samples. It achieves a limit of detection (LOD) as low as 1ppt, which is ~100 times more sensitive than conventional optical sensors. We anticipate that the proposed G-quadruplex-based nanosensor could be applied to the analysis of other metal ions and small molecules in environmental samples and biological systems.
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Affiliation(s)
- Min Liu
- College of Science, China Three Gorges University, Yichang 443002, Hubei, China; Advanced Photonics Center, Southeast University, 2# Sipai Lou, Nanjing 210096, Jiangsu, China.
| | - Zhuyuan Wang
- Advanced Photonics Center, Southeast University, 2# Sipai Lou, Nanjing 210096, Jiangsu, China
| | - Liqing Pan
- College of Science, China Three Gorges University, Yichang 443002, Hubei, China
| | - Yiping Cui
- Advanced Photonics Center, Southeast University, 2# Sipai Lou, Nanjing 210096, Jiangsu, China
| | - Yiman Liu
- College of Science, China Three Gorges University, Yichang 443002, Hubei, China.
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38
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Wu P, Du P, Zhang H, Cai C. Graphyne-supported single Fe atom catalysts for CO oxidation. Phys Chem Chem Phys 2015; 17:1441-9. [DOI: 10.1039/c4cp04181j] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We demonstrate that graphyne is a good substrate for single Fe atom catalysts, which have high catalytic activity for CO oxidation.
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Affiliation(s)
- Ping Wu
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Pan Du
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Hui Zhang
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
| | - Chenxin Cai
- Jiangsu Key Laboratory of New Power Batteries
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
- College of Chemistry and Materials Science
- Nanjing Normal University
- Nanjing 210097
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39
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Kumeria T, Rahman MM, Santos A, Ferré-Borrull J, Marsal LF, Losic D. Nanoporous anodic alumina rugate filters for sensing of ionic mercury: toward environmental point-of-analysis systems. ACS APPLIED MATERIALS & INTERFACES 2014; 6:12971-12978. [PMID: 25003595 DOI: 10.1021/am502882d] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Herein, we present an ultrasensitive, cost-competitive, and portable optical sensing system for detecting ionic mercury in environmental water. This analytical system combines structurally engineered and chemically modified nanoporous anodic alumina rugate filters (NAA-RFs) with reflection spectroscopy (RfS). The sensing performance of the proposed system is assessed through several tests, establishing its sensing performance (i.e., linear working range from 1 to 100 μM of Hg(2+), low limit of detection 1 μM of Hg(2+) ions (i.e., 200 ppb), and sensitivity of 0.072 nm μM(-1)), chemical selectivity (i.e., exposure to different metal ions Co(2+), Mg(2+), Ni(2+), Cu(2+), Pb(2+), Fe(3+), Ca(2+), Cr(6+), and Ag(+)) and metal ions binding mechanism (i.e., fitting to Langmuir and Freundlich isotherm models). Furthermore, the detection of Hg(2+) ions in tap and environmental water (River Torrens) is successfully carried out, demonstrating the suitability of this system for developing environmental point-of-analysis systems.
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Affiliation(s)
- Tushar Kumeria
- School of Chemical Engineering, The University of Adelaide , Adelaide, SA 5005, Australia
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40
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Maiti S, Pezzato C, Garcia Martin S, Prins LJ. Multivalent Interactions Regulate Signal Transduction in a Self-Assembled Hg2+ Sensor. J Am Chem Soc 2014; 136:11288-91. [DOI: 10.1021/ja506325e] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Subhabrata Maiti
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Cristian Pezzato
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Sergio Garcia Martin
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Leonard J. Prins
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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41
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Sett A, Das S, Bora U. Functional nucleic-acid-based sensors for environmental monitoring. Appl Biochem Biotechnol 2014; 174:1073-91. [PMID: 24903959 DOI: 10.1007/s12010-014-0990-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 05/19/2014] [Indexed: 01/16/2023]
Abstract
Efforts to replace conventional chromatographic methods for environmental monitoring with cheaper and easy to use biosensors for precise detection and estimation of hazardous environmental toxicants, water or air borne pathogens as well as various other chemicals and biologics are gaining momentum. Out of the various types of biosensors classified according to their bio-recognition principle, nucleic-acid-based sensors have shown high potential in terms of cost, sensitivity, and specificity. The discovery of catalytic activities of RNA (ribozymes) and DNA (DNAzymes) which could be triggered by divalent metallic ions paved the way for their extensive use in detection of heavy metal contaminants in environment. This was followed with the invention of small oligonucleotide sequences called aptamers which can fold into specific 3D conformation under suitable conditions after binding to target molecules. Due to their high affinity, specificity, reusability, stability, and non-immunogenicity to vast array of targets like small and macromolecules from organic, inorganic, and biological origin, they can often be exploited as sensors in industrial waste management, pollution control, and environmental toxicology. Further, rational combination of the catalytic activity of DNAzymes and RNAzymes along with the sequence-specific binding ability of aptamers have given rise to the most advanced form of functional nucleic-acid-based sensors called aptazymes. Functional nucleic-acid-based sensors (FNASs) can be conjugated with fluorescent molecules, metallic nanoparticles, or quantum dots to aid in rapid detection of a variety of target molecules by target-induced structure switch (TISS) mode. Although intensive research is being carried out for further improvements of FNAs as sensors, challenges remain in integrating such bio-recognition element with advanced transduction platform to enable its use as a networked analytical system for tailor made analysis of environmental monitoring.
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Affiliation(s)
- Arghya Sett
- Bioengineering Research Laboratory, Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
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42
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Liu M, Wang Z, Zong S, Chen H, Zhu D, Wu L, Hu G, Cui Y. SERS detection and removal of mercury(II)/silver(I) using oligonucleotide-functionalized core/shell magnetic silica sphere@Au nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2014; 6:7371-9. [PMID: 24738775 DOI: 10.1021/am5006282] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Heavy metal ions, such as Hg(2+) and Ag(+), pose severe risks in human health and the environment. For sensitive detection and selective removal of Hg(2+) and Ag(+) ions, here, we demonstrate a surface-enhanced Raman scattering (SERS)-active platform by employing the oligonucleotide-functionalized magnetic silica sphere (MSS)@Au nanoparticles (NPs). This system exploits mismatched T-Hg-T and C-Ag-C bridges to capture Hg(2+) and Ag(+) ions, exhibiting excellent responses for Hg(2+) ions in the range of 0.1-1000 nM and for Ag(+) in the range of 10-1000 nM. The assay is highly selective for the target ions and does not respond to other metal ions. Additionally, the Hg(2+) and Ag(+) ions in this system can be effectively removed from surrounding solutions by an external magnetic field or through spontaneous precipitation. Moreover, more than 80% of the MSS@Au NPs can be easily recycled with the help of cysteine. We anticipate that the designed strategy could be extended to other analytes that can bind to DNA molecules with a high affinity, and can be used in many potential applications such as environmental renovation, toxin detection, and groundwater analysis.
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Affiliation(s)
- Min Liu
- Advanced Photonics Center, Southeast University , 2# Sipai Lou, Nanjing 210096, Jiangsu China
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43
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Chen B, Wang Z, Hu D, Ma Q, Guo Z, Jiang X, Wang S. Determination of Nanomolar Levels of Mercury(II) by Exploiting the Silver Stain Enhancement of the Aggregation of Aptamer-Functionalized Gold Nanoparticles. ANAL LETT 2014. [DOI: 10.1080/00032719.2013.853183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Rapid on-site/in-situ detection of heavy metal ions in environmental water using a structure-switching DNA optical biosensor. Sci Rep 2014; 3:2308. [PMID: 23892693 PMCID: PMC3725506 DOI: 10.1038/srep02308] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/12/2013] [Indexed: 11/23/2022] Open
Abstract
A structure-switching DNA optical biosensor for rapid on-site/in situ detection of heavy metal ions is reported. Mercury ions (Hg2+), highly toxic and ubiquitous pollutants, were selected as model target. In this system, fluorescence-labeled DNA containing T-T mismatch structure was introduced to bind with DNA probes immobilized onto the sensor surface. In the presence of Hg2+, some of the fluorescence-labeled DNAs bind with Hg2+ to form T-Hg2+-T complexes through the folding of themselves into a hairpin structure and dehybridization from the sensor surface, which leads to decrease in fluorescence signal. The total analysis time for a single sample was less than 10 min with detection limit of 1.2 nM. The rapid on-site/in situ determination of Hg2+ was readily performed in natural water. This sensing strategy can be extended in principle to other metal ions by substituting the T-Hg2+-T complexes with other specificity structures that selectively bind to other analytes.
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45
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Abstract
Increasing interest in detecting metal ions in many chemical and biomedical fields has created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal-ion-dependent DNAzymes and metal-ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attachment of these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detection. These sensors are highly sensitive (with a detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of "dipstick tests", portable fluorometers, computer-readable disks, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal-ion sensing and imaging in many fields of applications.
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Affiliation(s)
- Yu Xiang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Fax: 217-244-3186; Tel: 217-333-2619
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46
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Jiang J, Ou-Yang L, Zhu L, Zou J, Tang H. Novel one-pot fabrication of lab-on-a-bubble@Ag substrate without coupling-agent for surface enhanced Raman scattering. Sci Rep 2014; 4:3942. [PMID: 24487575 PMCID: PMC3909904 DOI: 10.1038/srep03942] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/09/2014] [Indexed: 12/04/2022] Open
Abstract
Through in-situ reduction of silver nitrate without using any coupling-agent, a substrate for surface-enhanced Raman scattering (SERS) was prepared by coating silver on hollow buoyant silica microspheres as a lab on a bubble (LoB). The silver coated LoBs (LoBs@Ag) floated on surface of a solution could provide a very convenient platform for the detection of target molecules in the solution. The LoBs@Ag substrate not only immobilized well-distributed Ag nanoparticles on the surface LoBs, but excluded the interference of coupling agents. This yielded high-resolution SERS spectra with excellent reproducibility. The adsorption of crystal violet (CV) on the LoBs@Ag substrate was investigated by means of SERS combined with density functional theory (DFT) calculations. The LoBs@Ag substrate exhibited a remarkable Raman enhancement effect for CV with an enhancement factor of 6.9 × 10(8) and wide adaptability from dye, pesticide to bio-molecules. On the basis of this substrate, a simple and sensitive SERS method was proposed for the determination of trace organic pollutants or bio-molecules.
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Affiliation(s)
- Jizhou Jiang
- College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, P.R. China
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South Central University for Nationalities, Wuhan 430074, P.R. China
| | - Lei Ou-Yang
- College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, P.R. China
| | - Lihua Zhu
- College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, P.R. China
| | - Jing Zou
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan 430073, P.R. China
| | - Heqing Tang
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South Central University for Nationalities, Wuhan 430074, P.R. China
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47
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Nong G, Chen S, Xu Y, Huang L, Zou Q, Li S, Mo H, Zhu P, Cen W, Wang S. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor. Sci Rep 2014; 4:3572. [PMID: 24389750 PMCID: PMC3880959 DOI: 10.1038/srep03572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 12/02/2013] [Indexed: 12/28/2022] Open
Abstract
A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process.
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Affiliation(s)
- Guangzai Nong
- Center for Sugar Engineering and Technology Research, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Shan Chen
- Center for Sugar Engineering and Technology Research, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Yuanjin Xu
- State key laboratory for conservation and utilization of subtropical agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Lijie Huang
- Center for Sugar Engineering and Technology Research, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Qingsong Zou
- Center for Sugar Engineering and Technology Research, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Shiqiang Li
- Institute of Light Industry and Food Engineering, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Haitao Mo
- Center for Sugar Engineering and Technology Research, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Pingchuan Zhu
- State key laboratory for conservation and utilization of subtropical agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Weijian Cen
- State key laboratory for conservation and utilization of subtropical agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, P. R. China
| | - Shuangfei Wang
- Institute of Light Industry and Food Engineering, Guangxi University, Nanning, Guangxi, 530004, P. R. China
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48
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Bao WJ, Yan ZD, Wang M, Zhao Y, Li J, Wang K, Xia XH, Wang ZL. Distance-determined sensitivity in attenuated total reflection-surface enhanced infrared absorption spectroscopy: aptamer–antigen compared to antibody–antigen. Chem Commun (Camb) 2014; 50:7787-9. [DOI: 10.1039/c4cc01920b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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49
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Guo Z, Liu ZG, Yao XZ, Zhang KS, Chen X, Liu JH, Huang XJ. A molecular-gap device for specific determination of mercury ions. Sci Rep 2013; 3:3115. [PMID: 24178058 PMCID: PMC3814579 DOI: 10.1038/srep03115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/16/2013] [Indexed: 11/09/2022] Open
Abstract
Specific determination/monitoring of trace mercury ions (Hg(2+)) in environmental water is of significant importance for drinking safety. Complementarily to conventional inductively coupled plasma mass spectrometry and atomic emission/absorption spectroscopy, several methods, i.e., electrochemical, fluorescent, colorimetric, and surface enhanced Raman scattering approaches, have been developed recently. Despite great success, many inevitably encounter the interferences from other metal ions besides the complicated procedures and sophisticated equipments. Here we present a molecular-gap device for specific determination of trace Hg(2+) in both standardized solutions and environmental samples based on conductivity-modulated glutathione dimer. Through a self-assembling technique, a thin film of glutathione monolayer capped Au nanoparticles is introduced into 2.5 μm-gap-electrodes, forming numerous double molecular layer gaps. Notably, the fabricated molecular-gap device shows a specific response toward Hg(2+) with a low detection limit actually measured down to 1 nM. Theoretical calculations demonstrate that the specific sensing mechanism greatly depends on the electron transport ability of glutathione dimer bridged by heavy metal ions, which is determined by its frontier molecular orbital, not the binding energy.
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Affiliation(s)
- Zheng Guo
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Zhong-Gang Liu
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Xian-Zhi Yao
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Kai-Sheng Zhang
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Xing Chen
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Jin-Huai Liu
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Xing-Jiu Huang
- Nanomaterials and Environmental Detection Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
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