Co-reporter:Ying Zhao;Dong Xue;Honglan Qi
RSC Advances (2011-Present) 2017 vol. 7(Issue 37) pp:22882-22891
Publication Date(Web):2017/04/24
DOI:10.1039/C7RA01586K
A blue light emitting pyrene derivative, 1-methyl benzoate-pyrene (MB-Py), was synthesized by employing a pyrene moiety as the parent linked with a small electron-donating group, methyl benzoate. Owing to the introduction of methyl benzoate, there is an evident twisted configuration between the methyl benzoate moiety and the central pyrene core with a dihedral angle of 56°, confirmed by density functional theory (DFT) calculations. The basic photophysical, electrochemical and electrogenerated chemiluminescence (ECL) properties of MB-Py together with those of the parent pyrene (Py) and the analogue benzo[α]pyrene (Bz-Py) in MeCN : Bz (v/v = 1 : 1) were extensively characterized for the first time. The electrochemical behavior of MB-Py showed a quasi-reversible one-electron oxidation (E1/2 = +1.11 V vs. SCE) and two reversible closely spaced consecutive one-electron reductions (E1/2,1 = −2.12 V and E1/2,2 = −2.27 V vs. SCE). This redox behavior was confirmed by CV digital simulations and was consistent with the frontier molecular orbitals calculated. It was found that, unlike its parent Py and analogue Bz-Py, MB-Py showed a single-peaked absorption (343 nm) and a blue monomer photoluminescence (PL) emission (428 nm) with a large Stokes shift (85 nm). The electrogenerated radical ions of MB-Py are stable enough to produce an efficient ECL emission (439 nm) through ion annihilation with the S-route. The ECL spectra of MB-Py obtained in both the ion annihilation and coreactant processes are similar to the monomer PL spectrum. This nonplanar twisted conformation pyrene derivative imparts steric hindrance, prevents excimer formation and results in a high PL efficiency and efficient, stable blue ECL monomer emission. Owing to their rigid planar structures, Py and Bz-Py exhibited monomer and excimer blue-violet PL emissions and cyan/green ECL emissions, and could not be used as appropriate blue luminophores.
Co-reporter:Libin Yang;Danni Liu;Shuai Hao;Rongmei Kong;Abdullah M. Asiri;Xuping Sun
Journal of Materials Chemistry A 2017 vol. 5(Issue 16) pp:7305-7308
Publication Date(Web):2017/04/18
DOI:10.1039/C7TA00982H
Exploitation of efficient water oxidation electrocatalysts under benign conditions is of great importance but remains a huge challenge. In this communication, we report the preparation of a cobalt-borate nanosheet array on a Ti mesh (Co-Bi/Ti) successfully converted from an electrodeposited α-Co(OH)2 nanosheet array in potassium borate (K-Bi) via in situ electrochemical tuning. The Co-Bi/Ti shows high electrocatalytic activity toward water oxidation with an overpotential of 469 mV to achieve a current density of 10 mA cm−2 in 0.1 M K-Bi, with long-term electrochemical stability with a turnover frequency of 0.15 s−1 at an overpotential of 600 mV.
Co-reporter:Ying Zhao;Qiang Zhang;Ke Chen;Hongfang Gao;Honglan Qi;Xianying Shi;Yajun Han;Junfa Wei
Journal of Materials Chemistry C 2017 vol. 5(Issue 17) pp:4293-4301
Publication Date(Web):2017/05/04
DOI:10.1039/C7TC00314E
We synthesized and studied a new class of A–(π-D)3 type donor–acceptor molecular graphene, triphenothiazinyl triazacoronenes, [2,3,6,7,10,11-hexamethoxy-4,8,12-tri-(10-alkyl-phenothiazine)-1,5,9-triazacoronene] (TPTZ-TAC derivatives). These molecules have been synthesized by employing three electron-rich triphenothiazine (PTZ) groups as electron donors, which were linked to an electron acceptor of an electron-deficient triazacoronene core (2,3,6,7,10,11-hexamethoxy-1,5,9-triazacoronene, TAC). These donor–acceptor molecular graphenes exhibited unique multiple fluorescence and electro-generated chemiluminescence (ECL) emissions that are dependent on the concentration of these molecules, attributed to strong π-stacking interactions. The electrochemical behaviour showed two closely spaced consecutive reversible one-electron oxidations occurring on the PTZ groups and a reversible one-electron reduction localizing on the TAC core. The absorption and fluorescence emission spectra reveal that the electronic properties are affected by the intramolecular charge transfer (ICT) interaction from the PTZ donors to TAC acceptors in the excited state. The effect of π-stacking interaction was noticed for the excimer emission at the lower energy region. The ICT properties of the TPTZ-TACs have been analyzed by concentration-dependence and solvatochromism of fluorescence spectral studies. Remarkably, multiple ECL emissions were produced from the TPTZ-TAC derivatives via a radical ion annihilation and coreactant process through the formation of a charge-transfer excimer state. This work demonstrates that the attachment of electron-rich PTZ groups as electron donors to an electron-deficient TAC core as an electron acceptor, is a promising route to improve the optoelectronic properties of the molecular graphene TAC core. The D–A molecule excimers will represent a new approach to red luminescence and a means to enhance the fluorescence efficiency.
Co-reporter:Manman Dong, Xia Liu, Qian Dang, Honglan Qi, Yin Huang, Qiang Gao, Chengxiao Zhang
Analytica Chimica Acta 2016 Volume 906() pp:72-79
Publication Date(Web):4 February 2016
DOI:10.1016/j.aca.2015.11.047
•A sensitive and versatile ECL biosensing platform is developed for monitoring protein kinase activity and inhibition.•Ru(bpy)32+ functionalized gold nanoparticles are used as thiol-versatile signal probe.•The strategy exhibits unique advantages of high sensitivity, good selectivity and versatility.•The strategy is promising for multiple protein kinase assay and kinase inhibitor profiling.A novel, sensitive and versatile electrogenerated chemiluminescence biosensing platform is developed for monitoring activity and inhibition of protein kinase based on Ru(bpy)32+ functionalized gold nanoparticles (Ru(bpy)32+-AuNPs) mediated signal transduction. Ru(bpy)32+-AuNPs were formed by functionalizing AuNPs with Ru(bpy)32+ through electrostatic interactions and were used as thiol-versatile signal probe. Casein kinase II (CK2) and cAMP-dependent protein kinase (PKA), two classical protein kinase implicated in disease, were chosen as model protein kinases while a CK2-specific peptide (CRRRADDSDDDDD) and a PKA-specific peptide (CLRRASLG) were employed as molecular substrate for CK2 and PKA, respectively. The specific peptide was self-assembled onto the gold electrode via Au–S bond to form ECL biosensor. Upon thiophosphorylation of the peptide on the electrode in the presence of protein kinase and co-substrate adenosine-5’-(γ-thio)-triphosphate, Ru(bpy)32+-AuNPs was assembled onto the thiophosphorylated peptides via Au–S bond. The Ru(bpy)32+-AuNPs attached on electrode surface produce detectable ECL signal in the presence of coreactant tripropylamine. This strategy is promising for multiple protein kinase assay and kinase inhibitor profiling with high sensitivity, good selectivity and versatility. The ECL intensity is proportional to the activity of CK2 in the range of 0.01–0.5 unit/mL with a low detection limit of 0.008 unit/mL and to the activity of PKA in the range of 0.01–0.4 unit/mL with a detection limit of 0.005 unit/mL. Additionally, this assay was applied to the detection of CK2 in serum samples and the inhibition of CK2 and PKA. This work demonstrates that the developed ECL method can provide a sensitive and versatile platform for the detection of kinase activity and drug-screening.
Co-reporter:Lingzhi Zhao, Liu Zhao, Yanqing Miao, Chengxiao Zhang
Electrochimica Acta 2016 Volume 206() pp:86-98
Publication Date(Web):10 July 2016
DOI:10.1016/j.electacta.2016.04.117
A highly selective method for the electrochemical detection of reduced glutathione (GSH) has been developed on the basis of the product of a reaction between GSH and catechol as the electron mediator on single-walled carbon nanotubes modified glassy carbon electrode. A polymerization-adduct ECE mechanism at SWNTs/GCE was proposed. The oxidation peak potential was −0.160 V (vs. Ag/AgCl, sat. KCl) and the oxidation peak current showed a dependence relationship with GSH concentration in the range of 1.0 ∼500.0 μM with a detection limit of 0.5 μM GSH. The developed method can discriminate GSH from other thiol species such as L-cysteine (Cys) and cysteamine hydrochloride (Cym) within their certain concentration ranges. The as-established electrochemical method has been successfully applied for the determination of GSH from the leakage of intracellular GSH contents in HeLa cells following doxorubicin-induced cell apoptosis.
Co-reporter:Shunqin Xia, Danjuan Han, Hongfang Gao, Ying Zhao, Honglan Qi, Chengxiao Zhang
Journal of Electroanalytical Chemistry 2016 Volume 777() pp:101-107
Publication Date(Web):15 September 2016
DOI:10.1016/j.jelechem.2016.07.031
•Two cyclometalated iridium(III) complex, (pq)2Ir(sa) and (pq)2Ir(psa), were synthesized and characterized.•(pq)2Ir(sa) and (pq)2Ir(psa) show good solubility in water, lower oxidation potential and higher ECL efficiency.•Small amount of water can greatly increase the ECL intensity of two complexes in acetonitrile solvent.•The water-enhanced ECL pathway in the presence of TPA is proposed as a double coreactant ECL pathway.Two cyclometalated iridium(III) complexes, (pq)2Ir(sa) and (pq)2Ir(psa), with 2-phenylquinoline (pq) as the C^N main ligand and succinylacetone (sa) or 4,6-dioxo-6-phenylhexanoic acid (psa) as the O^O ancillary ligand, were synthesized at first time. The solubility was reached down to 0.1 mM for (pq)2Ir(sa) and 10 μM for (pq)2Ir(psa) in acetonitrile-water (v/v = 5:95) solution. The photophysical, electrochemical and electrogenerated chemiluminescence (ECL) properties of (pq)2Ir(sa) and (pq)2Ir(psa) in acetonitrile were mainly investigated. The oxidation peak potential of (pq)2Ir(sa) and (pq)2Ir(psa) appears at + 0.79 V and + 0.8 V vs SCE. (pq)2Ir(sa) and (pq)2Ir(psa) display orange ECL emission with a maximum wavelength at 621 nm and 610 nm, respectively. ECL efficiencies of (pq)2Ir(sa) and (pq)2Ir(psa) in acetonitrile containing tripropylamine were calculated to be 21.3-folds and 35.4-folds higher than that of Ru(bpy)32 +. It was surprised to find that small amount of water can greatly increase the ECL intensity of these two complexes in acetonitrile containing tripropylamine. The ECL methods for the determination of trace water in organic solvent were developed in the range from 0.02 to 4.0% (v/v) and 0.05 to 4.0% (v/v) with detection limit of 0.01% and 0.03% for (pq)2Ir(sa) and (pq)2Ir(psa), respectively. It was found that the O^O ancillary ligand played a key function in the water-enhanced ECL emission. A double coreactant ECL pathway is proposed for the water-enhanced ECL emission. This work demonstrates that (pq)2Ir(sa) and (pq)2Ir(psa) have lower potential and high ECL coefficient, which are promising for the effective use as ECL emitter in analytical application.
Co-reporter:Bing Wang, Rui Jing, Honglan Qi, Qiang Gao, Chengxiao Zhang
Journal of Electroanalytical Chemistry 2016 Volume 781() pp:212-217
Publication Date(Web):15 November 2016
DOI:10.1016/j.jelechem.2016.08.005
•Electrochemical impedance peptide-based biosensor for cardiac troponin I was developed.•The biosensors showed the low detection limit of 3.4 pg/mL cardiac troponin I.•Gold nanoparticles/carbon electrode can greatly reduce the background signal.•A suitable impedance analog circuit was designed.A label-free electrochemical impedance spectroscopy (EIS) biosensor for highly sensitive detection of cardiac troponin I (TnI) as a model target was developed by employing gold nanoparticle (GNPs) modified glassy carbon electrode (GCE) as a base electrode. A special peptide (CFYSHSFHENWPS) was used as molecular recognition probe. GNPs were firstly electrochemically deposited onto the surface of GCE and polyethylene glycol was then used to block any remaining sites of the surface of GCE. The biosensor was fabricated by thiol self-assembling the peptide probe onto the surface of gold nanoparticles and finally blocking any remaining sites of the surface of GNPs using 6-mercapto-1-hexanol. A suitable equivalent electrical circuit consisting of parallel double Randles circuit with phase angle elements greatly fits the experiment electrochemical cell. Upon the binding of TnI, the charge transfer resistance (Rct) of the biosensor was logarithmically direct proportional to the concentration of TnI in the range from 15.5 pg/mL to 1.55 ng/mL with a detection limit of 3.4 pg/mL. It was found that GNPs modified GCE as a platform for the immobilization of the peptide can greatly reduce the background EIS signal and enhance the EIS response to the target. This biosensor has been used for assay of real serum sample with satisfactory results. This work demonstrates that GNPs modified GCE for the immobilization of molecular recognition element is promising platform for the development of label-free electrochemical biosensors for the determination of special proteins.
Co-reporter:Haiying Yang, Qian Yang, Zhejian Li, Yingxin Du, Chengxiao Zhang
Sensors and Actuators B: Chemical 2016 Volume 236() pp:712-718
Publication Date(Web):29 November 2016
DOI:10.1016/j.snb.2016.04.030
A sensitive electrogenerated chemiluminescence (ECL) aptasensor was developed for the detection of human Burkitt’s lymphoma Ramos cells based on the cells-specific oligonucleotide TD05 served as a molecular recognition element and ruthenium(II) complex (Ru1) labeled polyamidoamine dendrimer (Dend) as a signal probe. Dend was used as platform to assemble substantial Ru1 and TD 05 to form Ru1-Dend-SH-(CH2)6-oligo(ethylene oxide)6-TD05 bioconjugate which was used as the signal probe. Dend was not only used as platform to assemble substantial Ru1 but also used as a coreactant of Ru1 to amplify the ECL signal. The biosensor platform was fabricated by covalently coupling the 52-mer amino-substituted oligonucleotide probes with carboxyl groups on single wall carbon nanotubes-coated glassy carbon electrode. With the sandwich assay, Ramos cells were selectively captured on the surface of the biosensor based on the specific affinity between aptamers and mIgM on the target cells surface, and then, the signal probe was bound with the captured cells. In the presence of tri-n-propylamine, the increased ECL intensity of the biosensor was logarithmically proportion to the concentration of Ramos cells over a range from 1.0 × 102 to 1.0 × 104 cells/mL with a detection limit of 55 cells/mL. It was found that the sensitivity of the biosensor increased 4.3-fold by comparison with that without Dend. And also, the ECL biosensor showed satisfied selectivity against the tested control cancer cells.
Co-reporter:Jing Zhang, Honglan Qi, Zhejian Li, Ni Zhang, Qiang Gao, and Chengxiao Zhang
Analytical Chemistry 2015 Volume 87(Issue 13) pp:6510
Publication Date(Web):June 1, 2015
DOI:10.1021/acs.analchem.5b01396
A novel electrogenerated chemiluminescence (ECL) bioanalytic system based on biocleavage of a ECL probe and homogeneous detection was designed and utilized for the first time for highly sensitive quantification of proteases to overcome drawbacks from probes directly immobilized on electrodes and commercial ECL biosystems, based on bioaffinity reactions. Prostate-specific antigen (PSA) was taken as a model analyte and ruthenium complex-tagged specific peptide (CHSSKLQK) was designed as an ECL probe (peptide-Ru1). ECL bioconjugated magnetic beads were synthesized through a simple solid-phase synthesis. When analyte PSA was introduced into the suspension of ECL bioconjugated magnetic beads, a biocleavage of the peptide occurred and the cleaved Ru1 part was released from the magnetic beads. ECL measurement was carried out in the presence of co-reactant tripropylamine, using two models. One is homogeneous ECL detection on a bare graphite pencil electrode (PGE), and the other is enriching ECL detection after the cleaved Ru1 part of the peptide was concentrated into the surface film of Nafion/gold nanoparticles modified PGE (AuNPs/Nafion/PGE). The extremely low detection limit of 80 fg/mL and high reproducibility (relative standard deviation (RSD) of 5.4% for six measurements of 0.5 pg/mL) for the detection of PSA were achieved at AuNPs/Nafion/PGE. This work demonstrates that the bioanalytic system designed can not only quantify proteases with high sensitivity and selectivity, but also diminish the complicated electrode process and improve the reproducibility by conducting the biocleavage and transduction steps at different surfaces. It can be easily extended for ECL analysis of other proteases in this system and other detection techniques, including optics and electrochemistry.
Co-reporter:Haiying Yang, Zhejian Li, Meng Shan, Congcong Li, Honglan Qi, Qiang Gao, Jinyi Wang, Chengxiao Zhang
Analytica Chimica Acta 2015 Volume 863() pp:1-8
Publication Date(Web):10 March 2015
DOI:10.1016/j.aca.2014.09.001
•A novel biosensor was developed for the detection of prostate cancer cells.•The selectivity of the biosensor was improved using antibody as capture probe.•The biosensor showed the low extremely detection limit of 2.6 × 102 cells mL−1.•The ruthenium complex-labelled WGA can be transported in the cell vesicles.A highly selective and sensitive electrogenerated chemiluminescence (ECL) biosensor for the detection of prostate PC-3 cancer cells was designed using a prostate specific antibody as a capture probe and ruthenium complex-labelled wheat germ agglutinin as a signal probe. The ECL biosensor was fabricated by covalently immobilising the capture probe on a graphene oxide-coated glassy carbon electrode. Target PC-3 cells were selectively captured on the surface of the biosensor, and then, the signal probe was bound with the captured PC-3 cells to form a sandwich. In the presence of tripropylamine, the ECL intensity of the sandwich biosensor was logarithmically directly proportion to the concentration of PC-3 cells over a range from 7.0 × 102 to 3.0 × 104 cells mL−1, with a detection limit of 2.6 × 102 cells mL−1. The ECL biosensor was also applied to detect prostate specific antigen with a detection limit of 0.1 ng mL−1. The high selectivity of the biosensor was demonstrated in comparison with that of a lectin-based biosensor. The strategy developed in this study may be a promising approach and could be extended to the design of ECL biosensors for highly sensitive and selective detection of other cancer-related cells or cancer biomarkers using different probes.
Co-reporter:Ying Zhao, Rui Zhang, Yiwei Xu, Honglan Qi, Xinbing Chen, Chengxiao Zhang
Journal of Electroanalytical Chemistry 2015 Volume 739() pp:28-35
Publication Date(Web):15 February 2015
DOI:10.1016/j.jelechem.2014.12.014
•The electrochemistry and ECL of benzoxazole derivatives were firstly reported.•The substituent effects on the electrochemical and ECL properties were studied.•All benzoxazole derivatives emit blue ECL emissions.•The substituents at 5-position of benzoxazole ring can modulate electrochemical properties.•The alkoxy chain length at 4′-position of biphenyl moiety has no effect on electrochemical properties.Benzoxazole derivatives, an important type of heterocyclic compounds, have attracted significant interest in photonics and electronics since they are highly efficient luminophores with high photo-stability. The electrochemistry and electrogenerated chemiluminescence (ECL) of benzoxazole derivatives were reported and the substituent effects on the electrochemical and ECL properties of benzoxazole derivatives were investigated in an acetonitrile:benzene (v:v = 1:1) solvent for the first time. The studied derivatives contain a 2-biphenyl benzoxazole moiety with the substituents (–CH3, –Cl, and –NO2 groups) at the 5-position of the benzoxazole ring and the alkoxy chains (CnH2n+1, n = 2–10) at the 4′-position of the biphenyl ring. The electrochemical and ECL behavior of benzoxazole derivatives were found to be dependent on the nature of the substituents at the 5-position of the benzoxazole ring but independent on the alkoxy chain length at 4′-position of biphenyl moiety. Under ion annihilation conditions, 5B–H (2-(4′-pentyloxy-biphenyl-4-yl)-benzoxazole), 5B–Me (2-(4′-pentyloxy- biphenyl-4-yl)-5-methylbenzoxazole), and 5B–Cl (2-(4′-pentyloxy-biphenyl-4-yl)-5-chlorobenzoxazole), display high ECL blue emission (ECL efficiencies are 0.51, 0.54, and 0.78 for 5B–H, 5B–Me, and 5B–Cl, respectively), while 5B-NO2 (2-(4′-pentyloxy-biphenyl-4-yl)-5-nitrobenzoxazole) does low ECL emission. In the presence of benzoyl peroxide, four derivatives exhibit strong ECL blue emissions. The results provide important electrochemical and ECL information of benzoxazole derivatives as well as their structure–properties relationships for future research.
Co-reporter:Honglan Qi, Min Li, Manman Dong, Sanpeng Ruan, Qiang Gao, and Chengxiao Zhang
Analytical Chemistry 2014 Volume 86(Issue 3) pp:1372
Publication Date(Web):January 17, 2014
DOI:10.1021/ac402991r
A novel electrogenerated chemiluminescence peptide-based biosensor (ECL-PB) for the determination of prostate-specific antigen (PSA) was developed on the basis of target-induced cleavage of a specific peptide within Nafion film incorporated with gold nanoparticles (AuNPs) and ECL emitting species. A specific peptide (CHSSKLQK) was used as a molecular recognition element; tris(2,2′-ripyridine) dichlororuthenium(II) (Ru(bpy)32+) was used as ECL emitting species, and ferrocene carboxylic acid (Fc) was employed as ECL quencher. The ECL-PB biosensor was fabricated by casting the mixture of Nafion and AuNPs onto the surface of glassy carbon electrode to form AuNPs/Nafion film, and then, Ru(bpy)32+ was electrostatically adsorbed into the AuNPs/Nafion film; finally, the peptide-tagged with ferrocene carboxylic acid (Fc-peptide) was self-assembled onto the surface of the AuNPs. When PSA was present, it specifically cleaved the Fc-peptide, leading the quencher to leave the electrode and resulting in the increase of the ECL intensity obtained from the resulted electrode in 0.1 M phosphate buffer saline (pH 7.4) containing tri-n-propylamine. The results showed that the increased ECL intensity was directly linear to the logarithm of the concentration of PSA in the range from 5.0 × 10–12 to 5.0 × 10–9 g/mL. An extremely low detection limit of 8 × 10–13 g/mL was achieved because of the signal amplification through AuNPs and the ECL background suppression through Fc as ECL quencher. This work demonstrates that the combination of the direct transduction of peptide cleavage events with the highly sensitive ECL method is a promising strategy for the design of enzymatic cleavage-based ECL biosensors with high sensitivity and selectivity.
Co-reporter:Zhejian Li, Honglan Qi, Haiying Yang, Qiang Gao and Chengxiao Zhang
Analytical Methods 2014 vol. 6(Issue 5) pp:1317-1323
Publication Date(Web):13 Dec 2013
DOI:10.1039/C3AY41978A
A highly sensitive electrogenerated chemiluminescence (ECL) adenosine aptasensor was designed by simply adsorbing a ruthenium complex-tagged aptamer on single-walled carbon nanotubes (SWNTs). A specific anti-adenosine binding aptamer was used as the recognition molecular element and ruthenium(II) complex (Ru1) was used as the ECL signal compound. Ru1-tagged aptamer was utilized as an ECL probe and the ECL probe was non-covalently assembled on the surface of the SWNTs to form an ECL probe/SWNTs composite. Analyte adenosine was bound with the aptamer of the ECL probe on the SWNTs so that the ECL probe was moved away or dropped from the SWNTs, resulting in the decrease of ECL signal. The results showed that the decreased ECL intensity was directly related to the logarithm of adenosine concentration in the range from 1.0 × 10−10 M to 5.0 × 10−7 M with a detection limit of 5.0 × 10−11 M. This work demonstrates that the strategy of simply adsorbing ECL probe/SWNTs composites as a biosensing platform is a promising approach to design ECL aptasensors with high sensitivity and selectivity.
Co-reporter:Zhejian Li, Lijuan Sun, Ying Zhao, Libin Yang, Honglan Qi, Qiang Gao, Chengxiao Zhang
Talanta 2014 Volume 130() pp:370-376
Publication Date(Web):1 December 2014
DOI:10.1016/j.talanta.2014.07.029
•A highly sensitive ECL aptasensor for thrombin was designed.•The auxiliary probe can enhance the sensitivity of the ECL aptasensor.•The recognition activities of the aptamer are not altered since it is not labeled.A novel electrogenerated chemiluminescence (ECL) aptasensor for ultrasensitive detection of thrombin incorporating an auxiliary probe was designed by employing specific anti-thrombin aptamer as a capture probe and a ruthenium(II) complex-tagged reporter probe as an ECL probe and an auxiliary probe to assist the ECL probe close to the surface of the electrode. The ECL aptasensor was fabricated by self-assembling a thiolated capture probe on the surface of gold electrode and then hybridizing the ECL probe with the capture probe, and further self-assembling the auxiliary probe. When analyte thrombin was bound with the capture probe, the part of the dehybridized ECL probe was hybridized with the neighboring auxiliary probe, led to the tagged ruthenium(II) complex close to the electrode surface, resulted in great increase in the ECL intensity. The results showed that the increased ECL intensity was directly related to the logarithm of thrombin concentrations in the range from 5.0×10−15 M to 5.0×10−12 M with a detection limit of 2.0×10−15 M. This work demonstrates that employing an auxiliary probe which exists nearby the capture probe can enhance the sensitivity of the ECL aptasensor. This promising strategy will be extended to the design of other biosensors for detection of other proteins and genes.
Co-reporter:Sanpeng Ruan;Zhejian Li;Honglan Qi;Qiang Gao
Microchimica Acta 2014 Volume 181( Issue 11-12) pp:1293-1300
Publication Date(Web):2014 August
DOI:10.1007/s00604-014-1252-3
We describe a highly sensitive electrochemiluminescence (ECL) based method for the determination of the human immunodeficiency virus-1 (HIV-1) gene. A long-range self-assembled double strand DNA (ds-DNA) is used as a carrier, and the ruthenium complex Ru(phen)32+ as an ECL indicator for signal amplification. The thiolated ss-DNA serving as a capture probe is firstly self-assembled on the surface of a gold electrode. After the target HIV-1 gene is completely hybridized with the capture probe, two previously hybridized auxiliary probes are hybridized with the target HIV-1 gene to form long-range supersandwich ds-DNA polymers on the surface of the electrode. Finally, the ECL indicator is intercalated into the supersandwich ds-DNA grooves. This results in a strongly increased ECL in tripropylamine solution because a large fraction of the intercalator is intercalated into supersandwich ds-DNA. The results showed that the increased ECL intensity is directly related to the logarithm of the concentration of the HIV-1 gene in the range from 0.1 pM to 0.1 nM, with a detection limit of 0.022 pM and using only 10 μL of analyte samples. The method can effectively discriminate target HIV-1 gene (a perfectly matched ss-DNA) from a 2-base mismatched ss-DNA. This work demonstrates that the high sensitivity and selectivity of an ECL DNA biosensor can be largely improved by using supersandwich ds-DNA along with ECL indicators.
Co-reporter:Meng Shan;Min Li;Xiaoying Qiu;Honglan Qi;Qiang Gao
Gold Bulletin 2014 Volume 47( Issue 1-2) pp:57-64
Publication Date(Web):2014 May
DOI:10.1007/s13404-013-0113-x
A sensitive electrogenerated chemiluminescence (ECL) peptide-based biosensor was fabricated for the determination of troponin I (TnI) by employing gold nanoparticles as amplification platform. Two specific peptides including peptide1 with a sequence of CFYSHSFHENWPS and peptide2 with a sequence of FYSHSFHENWPSK were employed as capture peptide and report peptide, respectively. The peptide2 was labeled with ruthenium bis(2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-N-hydroxysuccinimide ester (Ru(bpy)2(dcbpy)NHS) at NH2-containing lysine via acylation reaction and utilized as the ECL probe. Gold nanoparticles were electrodeposited onto gold electrode and used as an amplification platform. The peptide-based biosensor was fabricated by self-assembling peptide1 onto the surface of gold nanoparticles-modified gold electrode through a thiol-containing cysteine at the end of the peptide1. When the biosensor reacted with target TnI, and then incubated with the ECL probe, a strong ECL response was electrochemically generated. The ECL intensity is directly proportional to the logarithm of the concentration of TnI in the range from 1 to 300 pg/mL. The biosensor employing gold nanoparticles as amplification platform shows high sensitivity for the detection of TnI with a detection limit of 0.4 pg/mL (S/N = 3). Moreover, the biosensor is successfully applied to analysis of TnI in human serum sample. This work demonstrates that the combination of a highly binding peptide with nanoparticle amplification is a great promising approach for the design of ECL biosensor.
Co-reporter:Honglan Qi, Xiaoying Qiu, Danping Xie, Chen Ling, Qiang Gao, and Chengxiao Zhang
Analytical Chemistry 2013 Volume 85(Issue 8) pp:3886
Publication Date(Web):March 18, 2013
DOI:10.1021/ac4005259
An ultrasensitive electrogenerated chemiluminescence peptide-based (ECL-PB) method for the determination of cardiac troponin I (TnI) incorporating amplification of signal reagent-encapsulated liposome was reported for the first time. A synthesized short linear specific binding peptide (FYSHSFHENWPSK) was employed as a molecular recognition element for TnI, which was a reliable biomarker for detecting cardiac injury. Liposomes assembled using a standard sonication procedure were designed as the carrier of ECL signal reagents [bis(2,2′-bipyridine)-4,4′-dicarboxybipyridine ruthenium-di(N-succinimidyl ester) bis(hexafluorophosphate)] for signal amplification. The magnetic capture peptides for the enrichment of the target protein and magnetic separation were synthesized by covalently attaching the peptides to the surface of magnetic beads via an acylation reaction, and the liposome peptides were synthesized by covalently attaching the peptides to the signal reagent-encapsulated liposomes. In the presence of TnI, sandwich-type conjugates were generated in incubation of the magnetic capture peptides and the liposome peptides. After a magnetic separation, the sandwich-type conjugates were treated with ethanol and, thus, a great number of the ECL reagents were released and measured by the ECL method at a bare glassy carbon electrode with a potential pulse of +1.15 V versus Ag/AgCl in the presence of tri-n-propylamine. The increased ECL intensity has good linearity with the logarithm of the TnI concentration in the range from 10 pg/mL to 5.0 ng/mL, with an extremely low detection limit of 4.5 pg/mL. The proposed ECL-PB method was successfully applied to the detection of TnI in human serum samples. This work demonstrated that the employment of the magnetic capture peptides for the enrichment of the target proteins and magnetic separation and the liposome peptides for the signal amplification and polyvalent binding motifs may open a new door to ultrasensitive detection of proteins in clinical analyses.
Co-reporter:Haiying Yang, Zhejian Li, Xiaomin Wei, Ru Huang, Honglan Qi, Qiang Gao, Chenzhong Li, Chengxiao Zhang
Talanta 2013 Volume 111() pp:62-68
Publication Date(Web):15 July 2013
DOI:10.1016/j.talanta.2013.01.060
A label-free electrochemical impedance spectroscopy (EIS) biosensor for the sensitive determination and discrimination of alpha-fetoprotein (AFP) was developed by employing wheat-germ agglutinin (WGA) lectin as molecular recognition element. The EIS biosensor was fabricated by adsorbing carboxyl-functionalized single-wall carbon nanotubes (SWNTs) onto a screen-printed carbon electrode (SPCE) and subsequently covalently coupling WGA onto the surface of the SWNTs-modified electrode. Upon binding of AFP to the biosensor, the electron transfer resistance was increased and the increase in the electron transfer resistance was linearly proportional to the logarithm of the concentration of AFP in the range from 1 to 100 ng/L with a detection limit of 0.1 ng/L. It was found that the employment of SWNTs as immobilization platform could reduce the background and enhance the EIS response. Moreover, the lectin-based biosensor array fabricated with different lectins was used to evaluate the glycan expression of AFP N-glycan and discriminate AFP between healthy and cancer patients serum samples. This work demonstrates that the employment of carbon nanotubes as immobilization platform and lectin as molecular recognition element in biosensor array is a promising approach for the determination and discrimination of glycoproteins for cancer diagnosis. The strategy proposed in this work could further be used for high-throughput, label-free profiling of the glycan expression of cancer-related glycoproteins and to develop methods for cancer diagnosis in the early stages.Highlights► An EIS biosensor for the determination of AFP was developed. ► Lectin was employed as the molecular recognition element. ► The detection limit for AFP was 0.1 ng/L. ► A biosensor array was used to evaluate the glycan expression of AFP N-glycan. ► A biosensor array was used to discriminate AFP between healthy and cancer serums.
Co-reporter:Dongdong Zhang, Lei Fu, Lei Liao, Boya Dai, Rui Zou, Chengxiao Zhang
Electrochimica Acta 2012 Volume 75() pp:71-79
Publication Date(Web):30 July 2012
DOI:10.1016/j.electacta.2012.04.074
This paper describes preparation and characterization of electrochemically functional graphene nanostructure incorporating adsorption of electroactive methylene blue (MB) dye onto graphene and nanocomposite assembled using layer-by-layer of graphene with MB on solid substrates. UV–visible spectroscopy, FT-IR spectroscopy, Raman spectroscopy and electrochemistry for systematical characterization of the MB adsorption onto graphene reveal the formation of a MB/graphene adsorptive nanostructure through π–π stacking and hydrophobic interactions. Compared with MB adsorbed onto a graphene oxide (GO) modified electrode and MB adsorbed onto a GC electrode, MB adsorbed onto a graphene modified electrode exhibits a good stability and distinct electrochemical properties. Additionally, MB adsorbed onto graphene can improve the water-disperse ability of graphene. Furthermore, scanning electron microscopy, UV–vis-NIR spectroscopy and electrochemistry demonstrated that directly layer-by-layer assembling of MB and graphene was an excellent route to prepare a functional nanocomposite on different solid substrates including silica plate, quartz slide and glassy carbon electrode. The excellent electroactivity and the high stability of electrochemically functional graphene nanostructure and the layered nanocomposite are envisaged to make them very useful electrochemically functional nanomaterials for practical development of electronic devices such as biosensors and photovoltaic cells.
Co-reporter:Honglan Qi, Chen Ling, Qingyun Ma, Qiang Gao and Chengxiao Zhang
Analyst 2012 vol. 137(Issue 2) pp:393-399
Publication Date(Web):17 Nov 2011
DOI:10.1039/C1AN15698E
A novel electrochemical immunosensor array for the simultaneous detection of multiple tumor markers was developed by incorporating electrochemically addressing immobilization and one signal antibody strategy. As a proof-of-principle, an eight-electrode array including six carbon screen-printed working electrodes was used as a base array for the analysis of two important tumor markers, carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) and a horseradish peroxidase-labeled antibody was employed as a signal antibody. The immunosensor in the array was fabricated in sequence by covalently coupling the capture antibody onto the surface of the desired working electrode, which was firstly electrochemically addressably grafted with an aminophenyl group by reduction of in situ generated aminophenyl diazonium cation generated from p-phenylenediamine, using glutaraldehyde as cross-linker. This allowed the selective immobilization of the capture antibody at the desired position on a single array via an electrochemical operation. The immunoassay in sandwich mode was performed by specifically binding the targets, second antibodies and one signal antibody to the immunosensor array. The result showed that the steady current density was directly proportional to the concentration of target CEA/AFP in the range from 0.10 to 50 ng mL−1 with a detection limit of 0.03 ng mL−1 for CEA and 0.05 ng mL−1 for AFP (S/N = 3), respectively. This work demonstrates that the employment of an electrochemically addressing method for the fabrication of an immunosensor array and one signal antibody is a promising approach for the determination of multiple tumor markers in clinical samples.
Co-reporter:Fen Ma, Yu Zhang, Honglan Qi, Qiang Gao, Chengxiao Zhang, Wujian Miao
Biosensors and Bioelectronics 2012 Volume 32(Issue 1) pp:37-42
Publication Date(Web):15 February 2012
DOI:10.1016/j.bios.2011.11.011
A novel electrogenerated chemiluminescence (ECL) biosensor for highly sensitive and selective detection of mercury ion was developed on the basis of mercury-specific oligonucleotide (MSO) served as a molecular recognition element and the ruthenium(II) complex (Ru1) as an ECL emitting species. The biosensor was fabricated on a glassy carbon electrode coated with a thin layer of single wall carbon nanotubes, where the ECL probe, NH2-(CH2)6-oligo(ethylene oxide)6-MSO ↔ Dend-Ru1, was covalently attached. The Dend-Ru1 pendant was prepared by covalent coupling Ru1 with the 4th generation polyamidoamine dendrimer (Dend), in which each dendrimer contained 35 Ru1 units so that a large amplification of ECL signal was obtained. Upon binding of Hg2+ to thymine (T) bases of the MSO, the T–Hg–T structure was formed, and the MSO changed from its linear shape to a “hairpin” configuration. Consequently, the Dend-Ru1 approached the electrode surface resulting in the increase of anodic ECL signal in the presence of the ECL coreactant tri-n-propylamine. The reported biosensor showed a high reproducibility and possessed long-term storage stability (92.3% initial ECL recovery over 30 day's storage). An extremely low detection limit of 2.4 pM and a large dynamic range of 7.0 pM to 50 nM Hg2+ were obtained. An apparent binding constant of 1.6 × 109 M−1 between Hg2+ and the MSO was estimated using an ECL based extended Langmuir isotherm approach involving multilayer adsorption. Determination of Hg2+ contents in real water samples was conducted and the data were consistent with the results from cold vapor atomic fluorescence spectroscopy.Highlights► A novel electrogenerated chemiluminescence biosensor for highly sensitive and selective detection of Hg2+ was fabricated on a carbon electrode coated with a thin layer of single wall carbon nanotubes and then covalently attached with the probe consisting of a mercury-specific oligonucleotide-polyamidoamine dendrimer carried with the ruthenium(II) complex. ► The each dendrimer contained 35 Ru1 units led to a large amplification of the signal. ► The biosensor showed an extremely low detection limit of 2.4 pM and a dynamic range from 7.0 pM to 50 nM Hg2+.
Co-reporter:Dongdong Zhang;Lei Fu;Lei Liao;Nan Liu;Boya Dai
Nano Research 2012 Volume 5( Issue 12) pp:875-887
Publication Date(Web):2012 December
DOI:10.1007/s12274-012-0271-9
Co-reporter:Haiying Yang, Yaqin Wang, Honglan Qi, Qiang Gao, Chengxiao Zhang
Biosensors and Bioelectronics 2012 Volume 35(Issue 1) pp:376-381
Publication Date(Web):15 May 2012
DOI:10.1016/j.bios.2012.03.021
A novel electrogenerated chemiluminescence (ECL) biosensor for highly sensitive detection of Escherichia coli (E. coli) was first developed by employing Concanavalin A (Con A) as a biological recognition element and bis(2,2′-bipyridine)-4′-methyl-4-carboxybipyridine ruthenium (II) (Ru1) complex as the detector. The ECL biosensor was fabricated by adsorbing carboxyl-functionalised single-wall carbon nanotubes (SWNTs) onto a paraffin-impregnated graphite electrode and further covalently coupling the Ru1–Con A probe onto the surface of the SWNT-modified electrode. Upon the binding of E. coli O157:H7 (as a model target), the biosensor showed a decreased ECL intensity in the presence of tri-n-propylamine (TPrA), which was in logarithmically direct proportion to the concentration of E. coli over a range from 5.0 × 102 to 5.0 × 105 cells/mL. The detection limit of this sensor was 127 cells/mL. Additionally, the ECL biosensor also showed satisfactory selectivity in discriminating gram-negative E. coli from gram-positive bacteria. The strategy developed in this study may be a promising approach and could be extended to the design of ECL biosensors for highly sensitive and rapid detection of other desired bacteria.Highlights► An electrogenerated chemiluminescence biosensor for Escherichia coli detection was fabricated by coating a thin layer of single wall carbon nanotubes on a graphite electrode and then covalently attached with ruthenium complex-Concanavalin A taken as the probe. ► The biosensor showed an extremely low detection limit of 127 cells/mL Escherichia coli O157:H7 without enrichment and separation steps. ► Additionally, the ECL biosensor also showed satisfactory selectivity in discriminating gram-negative Escherichia coli from gram-positive bacteria.
Co-reporter:Fen Ma, Bo Sun, Honglan Qi, Hongge Zhang, Qiang Gao, Chengxiao Zhang
Analytica Chimica Acta 2011 Volume 683(Issue 2) pp:234-241
Publication Date(Web):10 January 2011
DOI:10.1016/j.aca.2010.10.030
A highly reproducible and sensitive signal-on electrogenerated chemiluminescence (ECL) biosensor based on the DNAzyme for the determination of lead ion was developed. The ECL biosensor was fabricated by covalently coupling 5′-amino-DNAzyme-tagged with ruthenium bis (2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-ethylenediamine (Ru1-17E′) onto the surface of graphite electrode modified with 4-aminobenzoic acid, and then a DNA substrate with a ribonucleotide adenosine hybridized with Ru1-17E′ on the electrode. Upon binding of Pb2+ to the Ru1-17E′ to form a complex which catalyzed the cleavage of the DNA substrate, the double-stranded DNA was dissociated and thus led to a high ECL signal. The signal linearly increases with the concentration of Pb2+ in the range from 5.0 to 80 pM with a detection limit of 1.4 pM and a relative standard derivation of 2.3%. This work demonstrates that using DNAzyme tagged with ruthenium complex as an ECL probe and covalently coupling method for the fabrication of the ECL biosensor with high sensitivity, good stability and significant regeneration ability is promising approach.
Co-reporter:Fen Ma;LiJuan Jia;Yu Zhang;Bo Sun;HongLan Qi;Qiang Gao
Science China Chemistry 2011 Volume 54( Issue 8) pp:
Publication Date(Web):2011 August
DOI:10.1007/s11426-011-4329-4
A novel electrogenerated chemiluminescence (ECL) aptasensor for highly sensitive detection of thrombin was developed on the basis of poly(pyrrole-co-pyrrole propylic acid) nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis(2,2′-bipyridine) (2,2′-bipyridine-4,4′-dicarboxylic acid)-ethylenediamine (Ru1) was used as an ECL signal complex. Novel electroactive polymers poly(pyrrole-co-pyrrole propylic acid) nanoparticles (Ppy-pa NPs) were synthesized by a simple alcohol-assisted microemulsion polymerization. Ru1-Ppy-pa NPs were synthesized by covalently coupling Ru1 with the Ppy-pa NPs. Ppy-pa NPs and Ru1-Ppy-pa NPs were characterized using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and transmission electron microscope. One ECL chemical sensor fabricated by immobilizing the Ru1-Ppy-pa NPs on PIGE was developed for the determination of TprA with a high sensitivity and stability. The ECL aptasensor was fabricated by covalently coupling the thrombin binding aptamer-I (TBA-I) onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations, for capturing thrombin onto the electrode and then the TBA-II labeled with Ru1-Ppy-pa NPs was bound with epitope of thrombin. The ECL aptasensor showed an extremely low detection limit of 3.0×l0−16 mol/L for thrombin and a good selectivity. This work demonstrated that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity.
Co-reporter:Hongge Zhang, Minjuan Wang, Qiang Gao, Honglan Qi, Chengxiao Zhang
Talanta 2011 Volume 84(Issue 3) pp:771-776
Publication Date(Web):15 May 2011
DOI:10.1016/j.talanta.2011.02.005
A novel fluorescent method for the detection of single nucleotide polymorphism (SNP) was developed using a hairpin DNA containing nucleotide base analog pyrrolo-deoxycytidine (P-dC) as a fluorescent probe. This fluorescent probe was designed by incorporating a fluorescent P-dC into a stem of the hairpin DNA, whose sequence of the loop moiety complemented the target single strand DNA (ss-DNA). In the absence of the target ss-DNA, the fluorescent probe stays a closed configuration in which the P-dC is located in the double strand stem of the fluorescent probe, such that there is weak fluorescence, attributed to a more efficient stacking and collisional quenching of neighboring bases. In the presence of target ss-DNA, upon hybridizing the ss-DNA to the loop moiety, a stem-loop of the fluorescent probe is opened and the P-dC is located in the ss-DNA, thus resulting in strong fluorescence. The effective discrimination of the SNP, including single base mismatch ss-DNA (A, T, G) and double mismatch DNA (C, C), against perfect complementary ss-DNA was achieved by increased fluorescence intensity, and verified by thermal denaturation and circular dichroism spectroscopy. Relative fluorescence intensity had a linear relationship with the concentration of perfect complementary ss-DNA and ranged from 50 nM to 3.0 μM. The linear regression equation was F/F0 = 2.73 C (μM) + 1.14 (R = 0.9961) and the detection limit of perfect complementary ss-DNA was 16 nM (S/N = 3). This study demonstrates that a hairpin DNA containing nucleotide base analog P-dC is a promising fluorescent probe for the effective discrimination of SNP and for highly sensitive detection of perfect complementary DNA.
Co-reporter:Bo Sun, Honglan Qi, Fen Ma, Qiang Gao, Chengxiao Zhang and Wujian Miao
Analytical Chemistry 2010 Volume 82(Issue 12) pp:5046
Publication Date(Web):May 21, 2010
DOI:10.1021/ac9029289
A double covalent coupling method for the fabrication of a highly sensitive and reusable electrogenerated chemiluminescence (ECL) chemical sensor for the detection of tertiary amines and ECL aptamer-based (ECL-AB) biosensor for the detection of cocaine is reported. The ECL sensors were constructed by covalent coupling of amino-containing Ru(bpy)32+ derivatives (Ru1, Ru(bpy)32+ = tris(2,2′-bipyridyl)ruthenium(II)) or cocaine aptamer-Ru1 to the surface of a paraffin-impregnated graphite electrode that had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations. ECL performance of the newly developed chemical sensors was evaluated using tri-n-propylamine (TPrA) and metoclopramide (MCP) as model analytes. The sensors exhibited excellent sensitivity, stability, and reproducibility with a detection limit of 30 nM for TPrA and 2.0 nM for MCP, and relative standard deviations (RSDs) of 2.1% over 90 cyclic potential cycles (0 to 1.50 V vs Ag/AgCl) and 2.6% over 45 cycles (0.60 to +1.30 V vs Ag/AgCl) at 400 mV/s for 50 nM TPrA and 200 nM MCP, respectively. For the ECL-AB biosensor, it showed an extremely low detection limit of 10 pM for cocaine, and offered a good selectivity toward cocaine, heroin, and caffeine. This detection limit was about 4−6 orders of magnitude lower than that reported on the basis of alternating current (AC) voltammetry and optical aptamer-based cocaine biosensors. Additionally, the ECL-AB biosensor was highly reusable (RSD = 2.8%, n = 7) and possessed long-term storage stability (96.8% initial ECL recovery over 21 days storage). A binding constant of 4.6 ± 0.3 × 109 M−1 between cocaine and its aptamer was estimated using an ECL based Langmuir isotherm approach. Wide ranging applications of the presently reported strategy in fabricating various chemical sensors or biosensors are expected.
Co-reporter:Yan Li, Honglan Qi, Qiang Gao, Jia Yang, Chengxiao Zhang
Biosensors and Bioelectronics 2010 Volume 26(Issue 2) pp:754-759
Publication Date(Web):15 October 2010
DOI:10.1016/j.bios.2010.06.044
Two electrogenerated chemiluminescence (ECL) aptasensors for the detection of thrombin were developed using the thrombin binding aptamer (TBA) taken as a molecular recognition element and nanomaterial as a carrier of the ECL capture/signal probe. In the “signal off” aptasensor, the thiolated capture probe (ss-DNA, 12-mer) was self-assembled on the gold nanoparticles (GNPs) which were self-assembled on the surface of gold electrode, and hybridized with six-base segment of the ss-DNA sequence (Tgt-aptamer, 21-mer) containing TBA-I (ss-DNA, 15-mer) tagged with ruthenium complex, producing a high ECL intensity. Introduction of the analyte thrombin triggered the dissociation of the Tgt-aptamer tagged with ruthenium complex from the aptasensors, led to significantly decrease in ECL intensity. The decreased ECL intensity was in proportion to the concentration of thrombin in a range from 2.7 × 10−12 to 2.7 × 10−9 M with a detection limit of 8 × 10−13 M. In the “signal on” aptasensor, the thiolated TBA-I was self-assembled on the gold electrode for capturing thrombin onto the electrode and then the TBA-II (ss-DNA, 29-mer) labeled with single-walled carbon-nanotubes (SWNT)-ECL tag was bound with epitope of thrombin, producing a high ECL intensity. The increased ECL intensity was linearly with the concentration of thrombin from 1.0 × 10−14 M to 1.0 × 10−11 M with a detection limit of 3 × 10−15 M. The present work demonstrates that using nanomaterial as a carrier for capture probe and signal probe is a promising way to amplify the ECL signal and to improve the sensitivity of the aptasensors.
Co-reporter:Dongdong Zhang, Yage Peng, Honglan Qi, Qiang Gao, Chengxiao Zhang
Biosensors and Bioelectronics 2010 Volume 25(Issue 5) pp:1088-1094
Publication Date(Web):15 January 2010
DOI:10.1016/j.bios.2009.09.032
A label-free electrochemical DNA biosensor array was developed as a model system for simultaneous detection of multiplexed DNAs using microlitres of sample. A novel multi-electrode array was comprised of six gold working electrodes and a gold auxiliary electrode, which were fabricated by gold sputtering technology, and a printed Ag/AgCl reference electrode was fabricated by screen-printing technology. The DNA biosensor array for simultaneous detection of the human immunodeficiency virus (HIV) oligonucleotide sequences, HIV-1 and HIV-2, was fabricated in sequence by self-assembling each of two kinds of thiolated hairpin-DNA probes onto the surfaces of the corresponding three working electrodes, respectively. The hybridization events were monitored by square wave voltammetry using methylene blue (MB) as a hybridization redox indicator. The oxidation currents of MB accumulated on the array decreased with increasing the concentration of HIVs due to higher affinity of MB for single strand rather than double strands of DNA. Under the optimized conditions, the peak currents were linear over ranges from 20 to 100 nM for HIV-1 and HIV-2, with the same detection limits of 0.1 nM (S/N = 3), respectively. The biosensor array showed a good specificity without the obvious cross-interference. Furthermore, single-base mutation oligonucleotides and random oligonucleotides can be easily discriminated from complementary target DNAs. This work demonstrates that different hairpin-DNA probes can be used to design the label-free electrochemical biosensor array for simultaneous detection of multiplexed DNA sequences for various clinical applications.
Co-reporter:Dongdong Zhang, Yage Peng, Honglan Qi, Qiang Gao, Chengxiao Zhang
Sensors and Actuators B: Chemical 2009 Volume 136(Issue 1) pp:113-121
Publication Date(Web):2 February 2009
DOI:10.1016/j.snb.2008.11.010
A novel multielectrode array modified with multiwall carbon nanotubes (MWCNTs) to simultaneous amperometric determination of dihydroxybenzene isomers was designed. The three oxidation peaks at the multielectrode array fabricated in 0.10 M KCl–0.20 M acetate buffer solution (pH 5.40) containing hydroquinone, catechol and resorcinol appeared at +0.192 V, +0.301 V and +0.683 V, corresponding to the oxidation of hydroquinone, catechol and resorcinol, respectively. A simple electrochemical method for simultaneous determination of dihydroxybenzene isomers was developed by multiple linear regression (MLR) method. Under the optimized conditions, the amperometric currents were linear over ranges from 1.0 × 10−6 M to 1.0 × 10−4 M for hydroquinone, from 1.0 × 10−6 M to 1.0 × 10−4 M for catechol and from 6.0 × 10−6 M to 1.0 × 10−4 M for resorcinol, with the detection limits of 3.0 × 10−7 M, 2.0 × 10−7 M and 6.0 × 10−7 M, respectively. The developed method has been applied to simultaneous determination of dihydroxybenzene isomers in artificial wastewater with a satisfactory recovery from 97% to 101%. This work demonstrates that the MWCNTs-modified multielectrode array incorporating multiple linear regression method is a promising strategy for simultaneous electrochemical determination of isomers of organic compounds.
Co-reporter:Yage Peng, Dongdong Zhang, Yan Li, Honglan Qi, Qiang Gao, Chengxiao Zhang
Biosensors and Bioelectronics 2009 Volume 25(Issue 1) pp:94-99
Publication Date(Web):15 September 2009
DOI:10.1016/j.bios.2009.06.001
A label-free and sensitive faradic impedance spectroscopy (FIS) aptasensor based on target-induced aptamer displacement was developed for the determination of lysozyme as a model system. The aptasensor was fabricated by self-assembling the partial complementary single strand DNA (pcDNA)–lysozyme binding aptamer (LBA) duplex on the surface of a gold electrode. To measure lysozyme, the change in interfacial electron transfer resistance of the aptasensor using a redox couple of [Fe(CN)6]3−/4− as the probe was monitored. The introduction of target lysozyme induced the displacement of the LBA from the pcDNA–LBA duplex on the electrode into the solution, decreasing the electron transfer resistance of the aptasensor. The decrease in the FIS signal is linear with the concentration of lysozyme in the range from 0.2 nM to 4.0 nM, with a detection limit of 0.07 nM. The fabricated aptasensor shows a high sensitivity, good selectivity and satisfactory regeneration. This work demonstrates that a high sensitivity of the fabricated aptasensor can be obtained using a relatively short pcDNA. This work also demonstrates that the target-induced aptamer displacement strategy is promising in the design of an electrochemical aptasensor for the determination of lysozyme with good selectivity and high sensitivity.
Co-reporter:Lihua Shen;Xiaoxia Li;Honglan Qi
Luminescence 2008 Volume 23( Issue 6) pp:370-375
Publication Date(Web):
DOI:10.1002/bio.1046
Abstract
Electrogenerated chemiluminescence (ECL) of a ruthenium complex polymer modified carbon paste electrode and its analytical applications were investigated. The ruthenium complex polymer was prepared using bis(2,2-bipyridine) (4,4-dicarboxy-2,2-bipyridine) ruthenium(II). The ECL behaviours of ruthenium complex polymer modified carbon paste electrode were investigated in the absence and presence of tripropylamine (TPA). The modified carbon paste electrode exhibited long-term stability and fine reproducibility. The ECL intensity of the modified carbon paste electrode was linear with the concentration of TPA in the range 2.0 × 10–6–3.8 × 10–3 mol/L, with a detection limit (S:N = 3) of 6 × 10–7 mol/L. It was also found that raceanisodamine could enhance the ECL intensity of the modified electrode. The ECL intensity of the modified carbon paste electrode was linear with the concentration of raceanisodamine in the range 1.1 × 10–5–6.0 × 10–4 mol/L, with a detection limit (S:N = 3) of 6 × 10–6 mol/L. This work demonstrates that the entrapment of ruthenium complex in a highly cross-linked polymer is a promising approach to construct an ECL modified electrode with long-term stability and fine reproducibility. The modified electrode designed has a potential application in the ECL detector. Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Xiaoxia Li, Lihua Shen, Dongdong Zhang, Honglan Qi, Qiang Gao, Fen Ma, Chengxiao Zhang
Biosensors and Bioelectronics 2008 Volume 23(Issue 11) pp:1624-1630
Publication Date(Web):15 June 2008
DOI:10.1016/j.bios.2008.01.029
A simple and highly sensitive electrochemical impedance spectroscopy (EIS) biosensor based on a thrombin-binding aptamer as molecular recognition element was developed for the determination of thrombin. The signal enhancement was achieved by using gold nanoparticles (GNPs), which was electrodeposited onto a glassy carbon electrode (GCE), as a platform for the immobilization of the thiolated aptamer. In the measurement of thrombin, the change in interfacial electron transfer resistance of the biosensor using a redox couple of [Fe(CN)6]3−/4− as the probe was monitored. The increase of the electron transfer resistance of the biosensor is linear with the concentration of thrombin in the range from 0.12 nM to 30 nM. The association and dissociation rate constants of the immobilized aptamer–thrombin complex were 6.7 × 103 M−1 s−1 and 1.0 × 10−4 s−1, respectively. The association and dissociation constants of three different immobilized aptamers binding with thrombin were measured and the difference of the dissociation constants obtained was discussed. This work demonstrates that GNPs electrodeposited on GCE used as a platform for the immobilization of the thiolated aptamer can improve the sensitivity of an EIS biosensor for the determination of protein. This work also demonstrates that EIS method is an efficient method for the determination of association and dissociation constants on GNPs modified GCE.
Co-reporter:Honglan Qi, Yi Zhang, Yage Peng, Chengxiao Zhang
Talanta 2008 Volume 75(Issue 3) pp:684-690
Publication Date(Web):15 May 2008
DOI:10.1016/j.talanta.2007.12.002
A homogeneous electrogenerated chemiluminescence (ECL) immunoassay for human immunoglobulin G (hIgG) has been developed using a N-(aminobutyl)-N-ethylisoluminol (ABEI) as luminescence label at gold nanoparticles modified paraffin-impregnated graphite electrode (PIGE). ECL emission was electrochemically generated from the ABEI-labeled anti-hIgG antibody and markedly increased in the presence of hIgG antigen due to forming a more rigid structure of the ABEI moiety. The concentration of hIgG antigen was determined by the increase of ECL intensity at a gold nanoparticles modified PIGE. It was found that the ECL intensity of ABEI in presence of hydrogen peroxide was dramatically enhanced at gold nanoparticles modified PIGE in neutral aqueous solution and the detection limit of ABEI was 2 × 10−14 mol/L (S/N = 3). The integral ECL intensity was linearly related to the concentration of hIgG antigen from 3.0 × 10−11 to 1.0 × 10−9 g/mL with a detection limit of 1 × 10−11 g/mL (S/N = 3). The relative standard deviation was 3.1% at 1.0 × 10−10 g/mL (n = 11). This work demonstrates that the enhancement of the sensitivity of ECL and ECL immunoassay at a nanoparticles modified electrode is a promising strategy.
Co-reporter:Yan Li, Honglan Qi, Fang Fang, Chengxiao Zhang
Talanta 2007 Volume 72(Issue 5) pp:1704-1709
Publication Date(Web):31 July 2007
DOI:10.1016/j.talanta.2007.01.062
An ultrasensitive electrogenerated chemiluminescence (ECL) detection method of DNA hybridization based on single-walled carbon-nanotubes (SWNT) carrying a large number of ruthenium complex tags was developed. The probe single strand DNA (ss-DNA) and ruthenium complex were loaded at SWNT, which was taken as an ECL probe. When the capture ss-DNA with a thiol group was self-assembled onto the surface of gold electrode, and then hybridized with target ss-DNA and further hybridized with the ECL probe to form DNA sandwich conjugate, a strong ECL response was electrochemically generated. The ECL intensity was linearly related to the concentration of perfect-matched target ss-DNA in the range from 2.4 × 10−14 to 1.7 × 10−12 M with a detection limit of 9.0 × l0−15 M. The ECL signal difference permitted to discriminate the perfect-matched target ss-DNA and two-base-mismatched ss-DNA. This work demonstrates that SWNT can provide an amplification platform for carrying a large number of ECL probe and thus resulting in an ultrasensitive ECL detection of DNA hybridization.
Co-reporter:Chengxiao Zhang;Meining Zhang;Honglan Qi
Luminescence 2007 Volume 22(Issue 1) pp:53-59
Publication Date(Web):27 JUL 2006
DOI:10.1002/bio.926
A highly sensitive homogeneous electrogenerated chemiluminescence (ECL) immunoassay for the determination of anti-digoxin antibody and digoxin hapten was developed employing Ru(bpy)2(dcbpy)NHS (bpy = 2,2′-bipyridyl; dcbpy = 2,2′-bipyridine-4,4′-dicarboxylic acid; NHS = N-hydroxysuccinimide ester) as an electrochemiluminescent label and bovine serum albumin (BSA) as a carrier protein. A digoxin hapten was indirectly heavily labelled with Ru(bpy)2(dcbpy)NHS through BSA to form Ru(bpy)2(dcbpy)NHS–BSA–digoxin conjugate. The ECL intensity of the immunocomplex of the conjugate with anti-digoxin antibody markedly decreased when the immunoreaction between Ru(bpy)2(dcbpy)NHS–BSA–digoxin conjugate and anti-digoxin antibody took place. Two formats, direct homogeneous immunoassay for anti-digoxin antibody and competitive immunoassay for digoxin, were developed to determine anti-digoxin antibody and digoxin, respectively. The anti-digoxin antibody concentration in the range 7.6 × 10−8–7.6 × 10−6 g/mL was determined by direct homogeneous format. Digoxin hapten was determined throughout the range 4.0 × 10−10–1.0 × 10−7 g/mL with a detection limit of 1.0 × 10−10 g/mL by competitive format. The relative standard derivation for 6.0 × 10−9 g/mL was 4.3%. The method has been applied to assaying digoxin in control human serum. Copyright © 2006 John Wiley & Sons, Ltd.
Co-reporter:Honglan Qi, Xiaoxia Li, Pei Chen, Chengxiao Zhang
Talanta 2007 Volume 72(Issue 3) pp:1030-1035
Publication Date(Web):15 May 2007
DOI:10.1016/j.talanta.2006.12.032
A sensitive electrochemical detection of DNA hybridization using a paste electrode assembled by multi-wall carbon nanotubes (MWNT) and immobilizing DNA probe within electropolymerized polypyrrole (ppy) was developed. The detection approach relied on entrapping of DNA probe within electropolymerized ppy film on the MWNT paste electrode and monitoring the current change generated from an electroactive intercalator of ethidium bromide (EB) after DNA hybridization. As a consequence of DNA hybridization, significant changes in the current of EB intercalated with double-stranded DNA (ds-DNA) on the MWNT paste electrode were observed. Based on the response of EB, only the complementary DNA sequence gave an obvious current signal compared with the five-point mismatched and non-complementary sequences. The oxidation peak current was linearly related to the logarithm of the concentration of the complementary DNA sequence from 1.0 × 10−10 to 1.0 × 10−8 M with a detection limit of 8.5 × 10−11 M. This work demonstrates that the incorporation of MWNT paste electrode with electropolymerization is a promising strategy of functional interfaces for the immobilization of biological recognition elements.
Co-reporter:Chengxiao Zhang;Honglan Qi
Luminescence 2004 Volume 19(Issue 1) pp:21-25
Publication Date(Web):18 FEB 2004
DOI:10.1002/bio.750
The electrogenerated chemiluminescence (ECL) reaction of lucigenin with isatin was investigated at a platinum electrode in a neutral aqueous solution. The ECL intensity of lucigenin at −0.65 V was greatly enhanced by isatin, and the ECL intensity was about 50 times higher than that of lucigenin without isatin. The enhanced ECL was believed to be produced by the chemiluminescence reaction between reduced lucigenin and superoxide anion that was generated by the reaction of electrochemically reduced isatin with dissolved oxygen. The conditions for the determination of isatin were optimized. Under the optimized condition, the enhanced ECL intensity vs. isatin concentration was linear in the range 4.8 × 10−7−1.9 × 10−5 g/mL; with a detection limit of 3.3 × 10−8 g/mL, and the relative standard derivation 1.0 × 10−6 g/mL isatin was 3.8%. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Lu Zhang, Yongqing Jin, Julia Lu, Chengxiao Zhang
Applied Geochemistry (May 2009) Volume 24(Issue 5) pp:
Publication Date(Web):1 May 2009
DOI:10.1016/j.apgeochem.2009.02.027
Samples of surface water, soil, sediment and plants from the Xunyang Hg mining area in Shaanxi Province, China, were analyzed to assess the effects of the Hg mining activities on the environment. The results show that: (1) the mining activities are sources of Hg to the environment surrounding the mine; (2) the environment, especially riverbeds in the Xunyang area, is contaminated with Hg and (3) Hg accumulation in cabbage leaves, the main vegetable for the local residents, is high, reaching concentrations that are 6–540 times higher than the maximum Hg concentration recommended for edible plants in China. Action should be taken to remediate contaminated sites, manage waste discharges and reduce the exposure of Hg to local residents by issuing advisories against consuming agricultural products grown in the area, which are contaminated with Hg.
Co-reporter:Li-Hua Shen, Hong-Ni Wang, Pei-Jing Chen, Chun-Xia Yu, Yao-Dong Liang, Cheng-Xiao Zhang
Journal of Food and Drug Analysis (January 2016) Volume 24(Issue 1) pp:199-205
Publication Date(Web):1 January 2016
DOI:10.1016/j.jfda.2015.09.002
A novel electrochemiluminescence (ECL) luminophor of amoxicillin was studied and found to generate ECL following the oxidation or reduction of amoxicillin. The amoxicillin oxidation state was also found to eliminate the reduction state, generating ECL. When solutions of amoxicillin were scanned between +1.5 V and −1.0 V with a graphite electrode in the presence of cetyltrimethyl ammonium bromide using KC1 as the supporting electrolyte, ECL emissions were observed at potentials of −0.7 V and +0.5 V. The ECL intensity at −0.7 V was enhanced by H2O2. Based on these findings, an ECL method for the determination of the amoxicillin concentration is proposed. The ECL intensities were linear with amoxicillin concentrations in the range of 1.8 × 10−8 g/mL to 2.5 × 10−7 g/mL, and the limit of detection (signal/noise = 3) was 5 × 10−9 g/mL. The florescence of amoxicillin had the greatest emission intensity in a neutral medium, with the emission wavelength dependent on the excitation wavelength. The experiments on the ECL mechanism for amoxicillin found that the electrochemical oxidation products of dissolved oxygen and active oxygen species contributed to the ECL process. The data also suggest that the hydroxyl group of amoxicillin contributed to its ECL emission.
Co-reporter:Ying Zhao, Qiang Zhang, Ke Chen, Hongfang Gao, Honglan Qi, Xianying Shi, Yajun Han, Junfa Wei and Chengxiao Zhang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 17) pp:NaN4301-4301
Publication Date(Web):2017/04/04
DOI:10.1039/C7TC00314E
We synthesized and studied a new class of A–(π-D)3 type donor–acceptor molecular graphene, triphenothiazinyl triazacoronenes, [2,3,6,7,10,11-hexamethoxy-4,8,12-tri-(10-alkyl-phenothiazine)-1,5,9-triazacoronene] (TPTZ-TAC derivatives). These molecules have been synthesized by employing three electron-rich triphenothiazine (PTZ) groups as electron donors, which were linked to an electron acceptor of an electron-deficient triazacoronene core (2,3,6,7,10,11-hexamethoxy-1,5,9-triazacoronene, TAC). These donor–acceptor molecular graphenes exhibited unique multiple fluorescence and electro-generated chemiluminescence (ECL) emissions that are dependent on the concentration of these molecules, attributed to strong π-stacking interactions. The electrochemical behaviour showed two closely spaced consecutive reversible one-electron oxidations occurring on the PTZ groups and a reversible one-electron reduction localizing on the TAC core. The absorption and fluorescence emission spectra reveal that the electronic properties are affected by the intramolecular charge transfer (ICT) interaction from the PTZ donors to TAC acceptors in the excited state. The effect of π-stacking interaction was noticed for the excimer emission at the lower energy region. The ICT properties of the TPTZ-TACs have been analyzed by concentration-dependence and solvatochromism of fluorescence spectral studies. Remarkably, multiple ECL emissions were produced from the TPTZ-TAC derivatives via a radical ion annihilation and coreactant process through the formation of a charge-transfer excimer state. This work demonstrates that the attachment of electron-rich PTZ groups as electron donors to an electron-deficient TAC core as an electron acceptor, is a promising route to improve the optoelectronic properties of the molecular graphene TAC core. The D–A molecule excimers will represent a new approach to red luminescence and a means to enhance the fluorescence efficiency.
Co-reporter:Libin Yang, Danni Liu, Shuai Hao, Rongmei Kong, Abdullah M. Asiri, Chengxiao Zhang and Xuping Sun
Journal of Materials Chemistry A 2017 - vol. 5(Issue 16) pp:NaN7308-7308
Publication Date(Web):2017/04/06
DOI:10.1039/C7TA00982H
Exploitation of efficient water oxidation electrocatalysts under benign conditions is of great importance but remains a huge challenge. In this communication, we report the preparation of a cobalt-borate nanosheet array on a Ti mesh (Co-Bi/Ti) successfully converted from an electrodeposited α-Co(OH)2 nanosheet array in potassium borate (K-Bi) via in situ electrochemical tuning. The Co-Bi/Ti shows high electrocatalytic activity toward water oxidation with an overpotential of 469 mV to achieve a current density of 10 mA cm−2 in 0.1 M K-Bi, with long-term electrochemical stability with a turnover frequency of 0.15 s−1 at an overpotential of 600 mV.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 5) pp:NaN1323-1323
Publication Date(Web):2013/12/13
DOI:10.1039/C3AY41978A
A highly sensitive electrogenerated chemiluminescence (ECL) adenosine aptasensor was designed by simply adsorbing a ruthenium complex-tagged aptamer on single-walled carbon nanotubes (SWNTs). A specific anti-adenosine binding aptamer was used as the recognition molecular element and ruthenium(II) complex (Ru1) was used as the ECL signal compound. Ru1-tagged aptamer was utilized as an ECL probe and the ECL probe was non-covalently assembled on the surface of the SWNTs to form an ECL probe/SWNTs composite. Analyte adenosine was bound with the aptamer of the ECL probe on the SWNTs so that the ECL probe was moved away or dropped from the SWNTs, resulting in the decrease of ECL signal. The results showed that the decreased ECL intensity was directly related to the logarithm of adenosine concentration in the range from 1.0 × 10−10 M to 5.0 × 10−7 M with a detection limit of 5.0 × 10−11 M. This work demonstrates that the strategy of simply adsorbing ECL probe/SWNTs composites as a biosensing platform is a promising approach to design ECL aptasensors with high sensitivity and selectivity.
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