247 results on '"Qin Yu"'
Search Results
2. Control of Liquid Crystal Microarray Optical Signals Using a Microspectral Mode Based on Photonic Crystal Structures
- Author
-
Yue Qi, Guannan Zhang, Jun Zhou, Fubing Xiao, Bing Liu, Zhaoyang Wu, Ru-Qin Yu, Qianshan Chen, and Shihong Wang
- Subjects
Optics and Photonics ,Photons ,Spectrometer ,business.industry ,Chemistry ,Aptamer ,Microarray Analysis ,Polarization (waves) ,Signal ,Fluorescence ,Liquid Crystals ,Analytical Chemistry ,Refractometry ,Reflection (mathematics) ,Liquid crystal ,Optoelectronics ,business ,Photonic crystal - Abstract
Herein, a novel liquid crystal microarray (LCM) film with optical regulation ability is first constructed by combining liquid crystals (LC) and the highly ordered microporous structure of inverse opal photonic crystals (IOPhCs). The LCM films are fabricated by infiltrating LC molecules into the LC polymer with the structure of IOPhCs, and their properties are very different from those without the LC. Interestingly, the optical property of LCM films can be controlled by changing the orientation of LC molecules, which varies with the interfacial force. In combination with polarization images, spectral reflection peak, circular dichroism spectra, potential difference, and fluorescence images of LCM films, the mechanism of this change is investigated. It is found that the exposed basic group of single-stranded DNA is the key to the change of the optical property of LC microarrays. Meanwhile, the optical signals of LC microarrays based on the PhCs provide a novel LC signal mode for an LC sensing system (microspectral signal mode), and it can be recorded by a fiber-optic spectrometer, which is a great improvement on LC sensing signals. Therefore, the LC microarray sensing signal can be used for accurate analysis of targets by the change of the reflection peak intensity of PhCs. When the LC molecules are induced by different aptamers, the LC microarray sensing interface can be further used for the determination of different targets, such as cocaine and Hg2+. The research on LCM films is of significant value for the development of LC sensing technology and also shows great application prospects in biochemical sensing fields.
- Published
- 2021
3. Single-Nanoparticle ICP-MS for Sensitive Detection of Uracil-DNA Glycosylase Activity
- Author
-
Bang-Rui Li, Jian-Hui Jiang, Hao Tang, and Ru-Qin Yu
- Subjects
Detection limit ,Chromatography ,biology ,Chemistry ,Hybridization probe ,010401 analytical chemistry ,Metal Nanoparticles ,Uracil ,010402 general chemistry ,01 natural sciences ,Enzyme assay ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Limit of Detection ,DNA glycosylase ,Colloidal gold ,Uracil-DNA glycosylase ,biology.protein ,Gold ,DNA Probes ,Uracil-DNA Glycosidase ,Inductively coupled plasma mass spectrometry - Abstract
Single-nanoparticle inductively coupled plasma mass spectrometry (SP-ICP-MS) has demonstrated unique advantages for the detection of biological samples. However, methods for enzyme activity detection based on SP-ICP-MS technology have been rarely explored. Here we report the development of a novel SP-ICP-MS assay for uracil-DNA glycosylase (UDG) activity detection based on its ability to specifically recognize and remove uracil to induce the cleavage of the DNA probe. Our design allows the generation of single gold nanoparticles correlated to the specific enzymatic reaction for a highly sensitive SP-ICP-MS measurement. The developed assay enables sensitive UDG activity detection with a detection limit of 0.0003 U/mL. The cell lysate analysis by the developed assay reveals its applicability for the detection of UDG activity in real samples. It is envisioned that our design may provide a new paradigm for developing the SP-ICP-MS assay for enzyme activity detection in biological samples.
- Published
- 2021
4. Single Molecule-Level Detection via Liposome-Based Signal Amplification Mass Spectrometry Counting Assay
- Author
-
Xiang-Cheng Lin, Fei Chen, Ke Zhang, Jishan Li, Jian-Hui Jiang, and Ru-Qin Yu
- Subjects
Nucleic Acids ,Liposomes ,Metal Nanoparticles ,Gold ,Mass Spectrometry ,Analytical Chemistry - Abstract
Because of the low atomization and/or ionization efficiencies of many biological macromolecules, the application of mass spectrometry to the direct quantitative detection of low-abundance proteins and nucleic acids remains a significant challenge. Herein, we report mass spectrum tags (MS-tags) based upon gold nanoparticle (AuNP)-templated phosphatidylcholine phospholipid (DSPC) liposomes, which exhibit high and reliable signals via electrospray ionization (ESI). Using these MS-tags, we constructed a liposome signal amplification-based mass spectrometric (LSAMS) "digital" counting assay to enable ultrasensitive detection of target nucleic acids. The LSAMS system consists of liposomes modified with a gold nanoparticle core and surface-anchored photocleavable DNA. In the presence of target nucleic acids, the modified liposome and a magnetic bead simultaneously hybridize with the target nucleic acid. After magnetic separation and photolysis, the MS-tag is released and can be analyzed by ESI-MS. At very low target concentrations, one liposome particle corresponds to one target molecule; thus, the concentration of the target can be estimated by counting the number of liposomes. With this assay, hepatitis C (HCV) virus RNA was successfully analyzed in clinical samples.
- Published
- 2022
5. Redox Homeostasis Alteration in Endothelial Mechanotransduction Monitored by Dual Stretchable Electrochemical Sensors
- Author
-
Fan, Wen-Ting, primary, Zhao, Yi, additional, Wu, Wen-Tao, additional, Qin, Yu, additional, Yan, Jing, additional, Liu, Yan-Ling, additional, and Huang, Wei-Hua, additional
- Published
- 2022
- Full Text
- View/download PDF
6. Biomineralized Zeolitic Imidazolate Framework-8 Nanoparticles Enable Polymerase-Driven DNA Biocomputing for Reliable Cell Identification
- Author
-
Dan-Dan Wang, Juan Zhang, Qiao-Qin Yu, Ke Zhang, Ting-Ting Chen, and Xia Chu
- Subjects
MicroRNAs ,Zeolites ,Nanoparticles ,DNA ,DNA, Catalytic ,Analytical Chemistry - Abstract
Investigating multiple miRNA expression patterns in living cells by DNA logic biocomputing is a valuable strategy for diagnosis and biomedical studies. The introduction of protein enzymes in DNA logic biocomputing circuits not only expands the toolbox of nucleic acid assembly techniques, but also further improves the specificity of recognizing and processing of DNA input. Herein, a polymerase-driven primer exchange reaction, acting as the sensing module, is introduced into the biocomputing system and transduces the multiple miRNAs sensing event into the intermediate triggers for activating the subsequent processing module, which further performs signal readout through DNAzyme catalytic substrate cleavage reaction. By using biomineralized zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) to deliver all the components of the biocomputing system, including polymerase and DNA probes, we realized polymerase-driven DNA biocomputing operations in living cells, including AND and OR gates. The results exhibited that biomineralized ZIF-8 NPs can protect the loaded cargoes against the external environment and deliver them efficiently to the cytoplasm. The polymerase-driven DNA biocomputing system based on multiple miRNAs sensing can be used for reliable cell identification and may provide a promising platform for more accurate diagnosis and programmable therapeutics.
- Published
- 2022
7. Programmable Self-Assembly of Protein-Scaffolded DNA Nanohydrogels for Tumor-Targeted Imaging and Therapy
- Author
-
Jian-Hui Jiang, Na Li, Jin-Wen Liu, Xiu-Yan Wang, Mei-Hao Xiang, and Ru-Qin Yu
- Subjects
Streptavidin ,Aptamer ,Antineoplastic Agents ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Cell Line, Tumor ,Humans ,Fluorescent Dyes ,Drug Carriers ,Microscopy, Confocal ,010401 analytical chemistry ,Hydrogels ,DNA ,Aptamers, Nucleotide ,Carbocyanines ,Nanostructures ,0104 chemical sciences ,Microscopy, Fluorescence ,chemistry ,Doxorubicin ,Cell culture ,Self-healing hydrogels ,Cancer cell ,Biophysics ,Self-assembly ,Drug Screening Assays, Antitumor ,Drug carrier - Abstract
DNA hydrogels are biocompatible and are suitable for many biomedical applications. However, to be useful imaging probes or drug carriers, the ordinary bulk size of DNA hydrogels must be overcome. Here we put forward a new strategy for fabricating a novel and simple protein-scaffolded DNA nanohydrogel, constructed through a direct DNA self-assembly using three types of streptavidin (SA)-based DNA tetrad for the activation of imaging and targeting therapy of cancer cells. The DNA nanohydrogels are easily prepared, and we show that by varying the initial concentration of DNA tetrad, it is possible to finely control their size within nanoscale range, which are favorable as carriers for intracellular imaging and transport. By further incorporating therapeutic agents and tumor-targeting MUC1 aptamer, these multifunctionalized SA-scaffolded DNA nanohydrogels (SDH) can specifically target cancer cells and selectively release the preloaded therapeutic agents via a structure switching when in an ATP-rich intracellular environment, leading to the activation of the fluorescence and efficient treatment of cancer cells. With the advantages of facile modular design and assembly, effective cellular uptake, and excellent biocompatibility, the method reported here has the potential for the development of new tunable DNA nanohydrogels with multiple synergistic functionalities for biological and biomedical applications.
- Published
- 2019
8. A Three-Dimensional Electrochemical Biosensor Integrated with Hydrogel Enables Real-Time Monitoring of Cells under Their In Vivo-like Microenvironment
- Author
-
Hu, Xue-Bo, primary, Qin, Yu, additional, Fan, Wen-Ting, additional, Liu, Yan-Ling, additional, and Huang, Wei-Hua, additional
- Published
- 2021
- Full Text
- View/download PDF
9. A Three-Dimensional Conductive Scaffold Microchip for Effective Capture and Recovery of Circulating Tumor Cells with High Purity
- Author
-
Cheng, Shi-Bo, primary, Chen, Miao-Miao, additional, Wang, Yi-Ke, additional, Sun, Zi-Han, additional, Qin, Yu, additional, Tian, Shan, additional, Dong, Wei-Guo, additional, Xie, Min, additional, and Huang, Wei-Hua, additional
- Published
- 2021
- Full Text
- View/download PDF
10. Cascade Circuits on Self-Assembled DNA Polymers for Targeted RNA Imaging In Vivo
- Author
-
Jin-Wen Liu, Jian-Hui Jiang, Xueli Zhu, Zhenkun Wu, Ru-Qin Yu, Zhan-Ming Ying, and Bin Qu
- Subjects
chemistry.chemical_classification ,Nuclease ,biology ,Cell Survival ,Aptamer ,RNA ,Polymer ,Aptamers, Nucleotide ,Analytical Chemistry ,Cell Line ,Molecular Imaging ,chemistry.chemical_compound ,MicroRNAs ,chemistry ,In vivo ,biology.protein ,Biophysics ,Humans ,A-DNA ,Molecular probe ,DNA Probes ,DNA - Abstract
DNA molecular probes have emerged as a powerful tool for RNA imaging. Hurdles in cell-specific delivery and other issues such as insufficient stability, limited sensitivity, or slow reaction kinetics, however, hinder the further application of DNA molecular probes in vivo. Herein, we report an aptamer-tethered DNA polymer for cell-specific transportation and amplified imaging of RNA in vivo via a DNA cascade reaction. DNA polymers are constructed through an initiator-triggered hybridization chain reaction using two functional DNA monomers. The prepared DNA polymers show low cytotoxicity and good stability against nuclease degradation and enable cell-specific transportation of DNA circuits via aptamer-receptor binding. Moreover, assembling the reactants of hairpins C1 and C2 on the DNA polymers accelerates the response kinetics and improves the sensitivity of the cascade reaction. We also show that the DNA polymers enable efficient imaging of microRNA-21 in live cells and in vivo via intravenous injection. The DNA polymers provide a valuable platform for targeted and amplified RNA imaging in vivo, which holds great implications for early clinical diagnosis and therapy.
- Published
- 2020
11. Magnesium-selective ion-channel mimetic sensor with a traditional calcium ionophore
- Author
-
Zhu, Jingwei, Qin, Yu, and Zhang, Yunhong
- Subjects
Ionophores -- Analysis ,Chemical detectors -- Analysis ,Chemistry - Abstract
A novel magnesium-selective ion-channel mimetic sensor based on a well-known calcium ionophore, ETH 5234, was demonstrated. Due to different stoichiometry of the ionophore with [Mg.sup.2+] and [Ca.sup.2+], the sensor exhibits high selectivity to [Mg.sup.2+] by controlling ionophore concentration on the electrode surface, which allows the measurement of [Mg.sup.2+] in a 1 mM [Ca.sup.2+] background solution. 10.1021/ac901570u
- Published
- 2010
12. Electrochemical sensor for mercury(II) based on conformational switch mediated by interstrand cooperative coordination
- Author
-
Si-Jia, Liu, Hua-Gui, Nie, Jian-Hui, Jiang, Guo-Li, Shen, and Ru-Qin, Yu
- Subjects
Electrochemical analysis -- Methods ,Electrochemical analysis -- Equipment and supplies ,Chemical detectors -- Research ,Mercury -- Identification and classification ,Mercury -- Measurement ,Chemistry - Abstract
A novel electrochemical sensor was developed for sensitive and selective detection of mercury(II), based on thymine--[Hg.sup.2+]--thymine (T--[Hg.sup.2+]--T) coordination chemistry. This strategy exploited the cooperativity of proximate poly-T oligonucleotides in coordination with [Hg.sup.2+]. Ferrocene (Fc)-tagged poly-T oligonucleotides were immobilized on the electrode surface via self-assembly of the terminal thiol moiety. In the presence of [Hg.sup.2+], a pair of poly-T oligonucleotides could cooperatively coordinate with [Hg.sup.2+], which triggered a conformational reorganization of the poly-T oligonucleotides from flexible single strands to relatively rigid duplexlike complexes, thus drawing the Fc tags away from the electrode with a substantially decreased redox current. The response characteristics of the sensor were thoroughly investigated using capillary electrophoresis and electrochemical measurements. The results revealed that the sensor showed a sensitive response to [Hg.sup.2+] in a concentration range from 1.0 nM to 2.0 [micro]M, with a detection limit of 0.5 nM. Also, this strategy afforded exquisite selectivity for [Hg.sup.2+] against a reservoir of other environmentally related metal ions, compared to existing anodic stripping voltammetry (ASV) techniques. In addition, this sensor could be implemented using minimal reagents and working steps with excellent reusability through mild regeneration procedure. It was expected that this cost-effective electrochemical sensor might hold considerable potential in on-site applications of [Hg.sup.2+] detection.
- Published
- 2009
13. Lipophilic polymer membrane optical sensor with a synthetic receptor for saccharide detection
- Author
-
Peng, Bo and Qin, Yu
- Subjects
Polymers -- Properties ,Carbohydrates -- Properties ,Membranes (Biology) -- Properties ,Chemical detectors -- Research ,Chemistry - Abstract
An optical sensing approach for the detection of saccharides based on reversible boronic acid--diol complexation in a lipophilic polymer membrane is presented. The complexation of saccharides with phenyl boronic acids that are immobilized in a hydrophobic polymer matrix produces a stable boronate anion and liberates a mobile hydrogen ion. The change in fluorescence intensity of the sensing films resulting from the increase in hydrogen ion concentration is thus directly related to the ambient saccharide concentration. By monitoring the pH change in a bulk optical film, we were able to detect D-glucose, D-fructose, D-galactose, and D-sorbitol with a concentration range from 0.1 to 100 mM at physiological pH 7.4.
- Published
- 2008
14. Single-Nanoparticle ICPMS DNA Assay Based on Hybridization-Chain-Reaction-Mediated Spherical Nucleic Acid Assembly
- Author
-
Jian-Hui Jiang, Hao Tang, Ru-Qin Yu, and Bang-Rui Li
- Subjects
chemistry.chemical_classification ,Chromatography ,Biomolecule ,010401 analytical chemistry ,Nanoparticle ,Nucleic Acid Hybridization ,DNA ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,Mass Spectrometry ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Nucleic acid thermodynamics ,chemistry ,Spherical nucleic acid ,Nucleic acid ,Nanoparticles ,Particle Size ,Inductively coupled plasma mass spectrometry - Abstract
The detection of nucleic acid is critical for clinic diagnostics. Single-nanoparticle inductively coupled plasma mass spectrometry (SP-ICPMS) has demonstrated unique advantages for nucleic acid detection. Here we report the development of a novel SP-ICPMS DNA assay based on a target-induced hybridization chain reaction to achieve controlled spherical nucleic acid assembly. The assembly process generated large gold nanoparticle aggregates, and the number of aggregates could be counted by SP-ICPMS, which was closely correlated to the concentration of the target DNA. This simple homogeneous assay could analyze DNA within the range of 5 fM to 10 pM with excellent selectivity and applicability for real sample analysis. It is envisioned that the developed approach might create a useful SP-ICPMS platform for biomolecule detection.
- Published
- 2020
15. Aptamer-based rolling circle amplification: a platform for electrochemical detection of protein
- Author
-
Long, Zhou, Li-Juan, Ou, Xia, Chu, Guo-Li, Shen, and Ru-Qin, Yu
- Subjects
Electrochemical analysis -- Methods ,Proteins -- Identification and classification ,Chemistry - Abstract
Aptamer-based rolling circle amplification (aptamer-RCA) was developed as a novel versatile electrochemical platform for ultrasensitive detection of protein. This method utilized antibodies immobilized on the electrode surface to capture the protein target, and the surface-captured protein was then sandwiched by an aptamer-primer complex. The aptamer-primer sequence mediated an in situ RCA reaction that generated hundreds of copies of a circular DNA template. Detection of the amplified copies via enzymatic silver deposition then allowed enormous sensitivity enhancement in the assay of target protein. This novel aptamer-primer design circumvented time-consuming preparation of the antibody-DNA conjugate for the common immuno-RCA assay. Moreover, the detection strategy based on enzymatic silver deposition enabled a highly efficient readout of the RCA product as compared to a redox-labeled probe based procedure that might exhibit low detection efficiency due to RCA product distance from the electrode. With the platelet-derived growth factor B-chain (PDGF-BB) as a model target, it was demonstrated that the presented method was highly sensitive and specific with a wide detection range of 4 orders of magnitude and a detection limit as low as 10 fM. Because of the wide availability of aptamers for numerous proteins, this platform holds great promise in ultrasensitive immunoassay.
- Published
- 2007
16. Branched Hybridization Chain Reaction Circuit for Ultrasensitive Localizable Imaging of mRNA in Living Cells
- Author
-
Han Wu, Xiang-Nan Wang, Ru-Qin Yu, Jin-Wen Liu, Jian-Hui Jiang, and Lan Liu
- Subjects
Cell studies ,Messenger RNA ,Chemistry ,Optical Imaging ,Nucleic Acid Hybridization ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Analytical Chemistry ,Coupling (electronics) ,Nucleic acid thermodynamics ,Spectrometry, Fluorescence ,Intense fluorescence ,Biophysics ,Humans ,RNA, Messenger ,0210 nano-technology ,human activities ,Chain reaction ,HeLa Cells ,Electronic circuit - Abstract
Hybridization chain reaction (HCR) circuits are valuable approaches to monitor low-abundance mRNA, and current HCR is still subjected to issues such as limited amplification efficiency, compromised localization resolution, or complicated designs. We report a novel branched HCR (bHCR) circuit for efficient signal-amplified imaging of mRNA in living cells. The bHCR can be realized using a simplified design by hierarchically coupling two HCR circuits with two split initiator fragments of the secondary HCR circuit incorporated in the probes for the primary HCR circuit. The bHCR circuit enables one to generate a hyperbranched assembly seeded from a single target initiator, affording the potential for localizing single target molecules in live cells. In vitro assays show that bHCR offers very high amplification efficiency and specificity in single mismatch discrimination with a detection limit of 500 fM. Live cell studies reveal that bHCR displays intense fluorescence spots indicating mRNA localization in living cells with improved contrast. The bHCR method can provide a useful platform for low-abundance biomarker detection and imaging for cell biology and diagnostics.
- Published
- 2018
17. Mitochondrion-Targeting, Environment-Sensitive Red Fluorescent Probe for Highly Sensitive Detection and Imaging of Vicinal Dithiol-Containing Proteins
- Author
-
Hai-Juan Liu, Ru-Qin Yu, Jian-Hui Jiang, Xian-Jun Liu, Fenglin Wang, Wen Chen, and Feng Liu
- Subjects
Fluorophore ,Mitochondrion ,010402 general chemistry ,01 natural sciences ,Arsenicals ,Analytical Chemistry ,chemistry.chemical_compound ,Limit of Detection ,Animals ,Humans ,Cysteine ,Bovine serum albumin ,Fluorescent Dyes ,Detection limit ,Oxadiazoles ,Microscopy, Confocal ,biology ,010405 organic chemistry ,Proteins ,Dithiol ,Serum Albumin, Bovine ,Ligand (biochemistry) ,Fluorescence ,Mitochondria ,0104 chemical sciences ,Microscopy, Fluorescence ,chemistry ,Biochemistry ,MCF-7 Cells ,biology.protein ,Cattle ,Vicinal - Abstract
Mitochondrial vicinal dithiol-containing proteins (VDPs) are key regulators in cellular redox homeostasis and useful markers for diagnostics of redox-dependent diseases. Current probes fail to target mitochondrial VDPs and show limited sensitivity and response rate. We develop a novel fluorescent probe using an engineered benzoxadiazole fluorophore that allows selective targeting of mitochondria and exhibits highly sensitive environment responsiveness. This probe is almost nonfluorescent in aqueous media, while delivering intense fluorescence upon binding to VDPs via a cyclic dithiaarsane ligand. The fluorescence probe is shown to have rapid response within 30 s and high sensitivity for detecting reduced bovine serum albumin (rBSA) in the concentration range from 0 to 0.1 μM with a detection limit of 2 nM. To our knowledge, this is the first fluorescence probe for VDPs which exhibits deep red emission, instantaneous response, high turn-on fluorescence ratio, and specific mitochondrial localization. It may provide a new tool for in situ monitoring mitochondrial VDPs.
- Published
- 2017
18. Fiber-optic microsensor array based on fluorescent bulk optode microspheres for the trace analysis of silver ions
- Author
-
Wygladacz, Katarzyna, Radu, Aleksandar, Xu, Chao, Qin, Yu, and Bakker, Eric
- Subjects
Ionization -- Research ,Silver compounds -- Chemical properties ,Fluorescence -- Usage ,Chemistry - Abstract
An optical microsensor array is described for the rapid analysis of silver ions at low parts per trillion levels. Because the ionophore o-xylylenebis(N,N-diisobutyldithio-carbamate) (Cu--I) was reevaluated and shown to exhibit excellent selectivity for silver ions, ion-selective electrode (ISE) membranes were optimized and found to exhibit the lowest reported detection limit so far (3 x [10.sup.10] M). A corresponding [Ag.sup.+]-selective fluorescent optical microsensor array for the rapid sensing of trace level [Ag.sup.+] was then developed. It was fabricated using plasticized PVC-based micrometer-scale fluorescent microspheres that were produced via a sonic particle casting device. They contained 156 mmol/kg Cu--I, 10 mmol/kg 9-(diethylamino)--5-[4-(15-buty1-1,13-dioxo-2,14-dioxanodecyl) phenylimino]-benzo[a]phenoxazine (chromoionophore VII, ETH 5418), 2.3 mmol/kg 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (internal reference dye), and 14 mmol/kg sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate and were deposited onto the etched distal end of a 3200-[micro]m-diameter optical fiber bundle. The microarray was characterized by fluorescence spectroscopy in samples containing [10.sup.12]--[10.sup.8] M AgN[O.sub.3] at pH 7.4, with selectivity characteristics comparable to the corresponding ISEs. The response time of the microsensor array was found to be less than 15 min for [10.sup.9] M AgN[O.sub.3], which is drastically shorter than earlier data on optode films (8 h) and corresponding ISEs (30 min). A detection limit of 4 x [10.sup.11] M for [Ag.sup.+] was observed, lower than any previously reported optode or silver-selective ISE. The microsensor array was applied for measurement of free silver levels in buffered pond water samples.
- Published
- 2005
19. Stretchable Electrode Based on Au@Pt Nanotube Networks for Real-Time Monitoring of ROS Signaling in Endothelial Mechanotransduction
- Author
-
Fan, Wen-Ting, primary, Qin, Yu, additional, Hu, Xue-Bo, additional, Yan, Jing, additional, Wu, Wen-Tao, additional, Liu, Yan-Ling, additional, and Huang, Wei-Hua, additional
- Published
- 2020
- Full Text
- View/download PDF
20. Elimination of dimer formation in In(III)porphyrin-based anion-selective membranes by covalent attachment of the ionophore
- Author
-
Qin, Yu and Bakker, Eric
- Subjects
Porphyrins -- Research ,Chemistry - Abstract
The spontaneous hydroxy-bridged dimer formation of metalloporphyrins in ion-selective membranes gives rise to a short sensor lifetime (typically days), triggered by solubility problems, the occurrence of a super-Nernstian response slope, and a pH cross response. This dimer formation is eliminated here by covalent attachment of the ionophore to the polymer matrix. Specifically, two different [indium.sup.III]porphyrins containing polymerizable groups, the chloride-selective chloro(3-[18-(3-acryloyloxypropyl)7,12-bis (1-methoxyethyl)-3,8,13,17-tetramethylporphy-rin-2-yl]propyl ester)indium(III) and the nitrite-selective Chloro(5-(4-acryloyloxyphenyl)-10,15,20-triphenylporphyrinato)indium(III), were synthesized and copolymerized with methyl methacrylate and decyl methacrylate. The covalent attachment of the ionophore to the polymer matrix indeed prevents the metalloporphyrin from forming dimeric species, as confirmed by UV/visible spectroscopy. The ion-selective membranes with grafted indium porphyrin showed Nernstian response slopes to chloride, nitrite, perchlorate, and thiocyanate anions, with a selectivity comparable to membranes with freely dissolved or underivatized metalloporphyrin. The membranes containing grafted ionophores showed a lifetime of at least two months, apparently since crystallization of the poorly soluble dimeric species may no longer occur. This is one of the first examples where the covalent attachment of an ionophore drastically improves on a number of important sensor characteristics.
- Published
- 2004
21. A copolymerized dodecacarborane anion as covalently attached cation exchanger in ion-selective sensors
- Author
-
Qin, Yu and Bakker, Eric
- Subjects
Vinyl chloride ,Polymers ,Decomposition (Chemistry) -- Analysis ,Electrodes -- Composition ,Ions ,Cations ,Chemistry, Analytic -- Research ,Chemical compounds ,Chemistry - Abstract
The traditional cation exchangers used in ion-selective electrodes and optodes are tetraphenylborate derivatives, which are generally adequate for most analytical applications but may in some cases suffer from decomposition by acid hydrolysis, oxidants, and light. Recently, halogenated dodecacarboranes were found to be improved cation exchangers in terms of lipophilicity and chemical stability. This forms the basis for the convenient covalent attachment of the cation exchanger to the polymeric backbone of the sensing material. This is a challenge that has not satisfactorily been solved and which is especially important in view of developing ultraminiaturized sensing arrays. Here, a C-derivative of the closo-dodecacarborane anion (C[B.sub.11][H.sub.12.sup.-]) with a polymerizable group was synthesized as a chemically stable cation exchanger. This new derivative was copolymerized with methyl methacrylate and decyl methacrylate (MMA-DMA) to fabricate a plasticizer-free polymer with cation-exchange properties. This polymer could be conveniently blended with traditional plasticized poly(vinyl chloride) or with noncrosslinked methacrylic polymers to give solvent cast films that appear to be clear and homogeneous and that could be doped with ionophores. Optode leaching experiments supported the covalent grafting of the carborane anions. Ion-selective membranes and optode thin films were evaluated in terms of response function, response time, and selectivity. In all cases, the new material exhibited behavior similar to free tetraphenylborate derivative-based membranes. As a result of these studies, an all-polymeric plasticizer-free calcium-selective membrane was fabricated on the basis of the covalently attached carborane, a recently introduced grafted calcium ionophore, and an MMA-DMA polymer matrix. The resulting ion-selective electrodes showed Nernstian response slopes and rapid response times, demonstrating that covalent grafting of all sensing components is a feasible approach to the development of ion sensors.
- Published
- 2003
22. Improving the detection Limit of anion-Selective electrodes: an iodide-selective membrane with a nanomolar detection limit
- Author
-
Malon, Adam, Radu, Aleksandar, Qin, Wei, Qin, Yu, Ceresa, Alan, Maj-Zurawska, Magdalena, Bakker, Eric, and Pretsch, Erno
- Subjects
Nanotechnology -- Usage ,Cations ,Iodides ,Ionophores ,Solution (Chemistry) ,Electrodes -- Composition ,Anions ,Chemistry, Analytic -- Research ,Chemistry - Abstract
The lower detection limit and the selectivity behavior of anion-selective electrodes (ISEs) are improved by using optimized inner solutions and membrane compositions. With a membrane based on the recently described ionophore [9]mercuracarborand-3, a detection limit of 2 x [10.sup.-9] M has been achieved for iodide. Nevertheless, the improvements are less pronounced than in the case of cation ISEs. This is mainly due to the fact that so far no anion ISE is known with the extremely high selectivities of cation ISEs. If the membrane does not contain an ionophore, leaching of the ion exchanger from the membrane into the sample is also a relevant limiting factor except for ion exchangers of very high lipophilicity.
- Published
- 2003
23. Plasticizer-free polymer containing a covalently immobilized [Ca.sup.2+]-selective ionophore for potentiometric and optical sensors
- Author
-
Qin, Yu, Peper, Shane, Radu, Aleksandar, Ceresa, Alan, and Bakker, Eric
- Subjects
Chemistry, Analytic -- Research ,Polymers -- Research ,Chemistry - Abstract
A derivative of a known [Ca.sup.2+]-selective ionophore, ETH 129, was synthesized to contain a polymerizable acrylic moiety (AU-1) and covalently grafted into a methyl methacrylate-co-decyl methacrylate polymer matrix. The polymer containing AU-1 was prepared via a simple one-step homogeneous polymerization method. It exhibited mechanical properties suitable for the fabrication of plasticizer-free ion-selective membrane electrodes and bulk optode films by solvent-casting and spin-coating techniques, respectively. The segmented sandwich membrane technique was utilized to assess the binding constant of free and covalently bound ionophores to calcium and to study their diffusion coefficients in the membrane phase. Diffusion was greatly diminished for the bound ionophore. This was confirmed in ion-selective electrode membranes containing no calcium ions in the inner solution, which should normally show apparent super-Nernstian response slopes in dilute calcium solutions. The response slope was Nernstian down to submicromolar concentration levels, indicating slow mass transport of calcium in the membrane. Optical-sensing films with the new copolymer matrix, unblended and blended with PVC-DOS, also confirmed that covalently bound ionophores are fully functional for maintaining selective ion extraction and binding properties of the sensing membrane.
- Published
- 2003
24. Ion-pairing ability, chemical stability, and selectivity behavior of halogenated dodecacarborane cation exchangers in neutral carrier-based ion-selective electrodes
- Author
-
Peper, Shane, Qin, Yu, Almond, Philip, McKee, Michael, Telting-Diaz, Martin, Albrecht-Schmitt, Thomas, and Bakker, Eric
- Subjects
Chemistry, Analytic -- Methods ,Electrodes -- Design and construction ,Ion exchange resins -- Composition ,Cations ,Chemistry - Abstract
Recently, it has been discovered that carba-closo-dodecaborates can be used as cation exchangers in neutral carrier-based ion-selective chemical sensors. Because of their inherent chemical stability and versatile functionalization chemistries, they offer many advantages that may potentially be exploited for ion analyses that require nontraditional sample conditions, including strongly acidic media. In this work, trimethylammonium salts of undecachlorinated (UCC), undecabrominated (UBC), hexabrominated (HBC), and undecaiodinated (UIC) carborane anions were prepared and evaluated for their potential use in solvent polymeric membrane-based sensors. Computational methods including Natural population analysis and electrostatic mapping were used to predict the ion-exchanging ability of each lipophilic anion. In addition, the sandwich membrane technique was used to evaluate the ion-pairing ability of each carborane anion in situ (i.e., within bis(2-ethylhexyl) sebacate (DOS)- and 2-nitrophenyl octyl ether (o-NPOE)-plasticized ISE membranes). The results of the computational and potentiometric studies found that binding affinity of the anions followed the generalized trend HBC > UCC > UBC > UIC. PVC-DOS bulk optode thin films containing the chromoionophore ETH 5315 and a respective anion were used to determine the chemical stability/lipophilicity of the carboranes and tetrakis[3,5-bis(trifluoromethyl)phenyl] borate (TFPB) in acidic media (0.2 M HOAc) under flowing conditions. The studies found that in terms of stability/lipophilicity UIC > UBC > TFPB [approximately equal to] UCC [much greater than] HBC. Electrodes containing a [Pb.sup.2+]-selective ionophore, tert-butylcalix[4]arene-tetrakis-(N,N-dimethylthioacetamide)(lead IV), were used to evaluate the functionality of each cation exchanger. An evaluation of response characteristics such as slope and selectivity found that UIC and UBC were quite comparable to the behavior of TFPB. Interestingly, both UIC and UBC showed a marked selectivity improvement over cadmium, with log [K.sup.pot.sub.Pb,Cd] values of -7.19 and -7.29, respectively, with TFPB giving a value of -5.89. Demonstrating excellent stability and suitable electrostatic properties, the carboranes, UIC in particular, are a very promising
- Published
- 2003
25. Mechanistic insights into the development of optical chloride sensors based on the [9]mercuracarborand-3 ionophore
- Author
-
Ceresa, Alan, Qin, Yu, Peper, Shane, and Bakker, Eric
- Subjects
Chemistry, Analytic -- Methods ,Sensors -- Design and construction ,Ionophores -- Usage ,Ions -- Analysis ,Chemistry - Abstract
Fluorescent sensing microspheres based on perhaps the most selective and practically useful chloride ionophore known, the recently reported [9]mercuracarborand-3 (MC-3), have been prepared and optimized for physiological measurements. In initial work, this ionophore was shown to yield functional optical sensing films in combination with an electrically neutral chromoionophore, ETH 5418. Unfortunately, however, these optodes suffered from unacceptably high levels of sodium interference under physiological conditions. To better understand the sensing mechanism, optical and potentiometric binding experiments were used to characterize the stoichiometry and the complex formation constants for this ionophore. It was found that the preferred stoichiometry is 1:2, rather than 1:1 as assumed earlier. The 1:2 complex is extremely stable (log [[beta].sub.2] = 13.4), but a relatively strong 1:1 complex also exists (log [K.sub.1] = 9.9). These characteristics were used to fabricate chloride optodes that make use of the stepwise ion-ionophore decomplexation equilibrium, by adding a calculated amount of lipophilic anion exchanger to the polymer film. Such optodes showed dramatically reduced sodium interference while maintaining the excellent selectivity of the traditional formulation. The optimized composition also shifted the measuring range to physiological conditions, making them useful for the assessment of chloride in undiluted and 10-fold-diluted blood at pH 7.4. After necessary alterations of the particle preparation procedure and sensor formulation, the new insights were used to fabricate mass-produced optical sensing microspheres with characteristics essentially identical to those of the optode sensing films.
- Published
- 2003
26. Evaluation of the separate equilibrium processes that dictate the upper detection limit of neutral ionophore-based potentiometric sensors
- Author
-
Qin, Yu and Bakker, Eric
- Subjects
Electrolytes -- Analysis ,Ionophores -- Analysis ,Chemistry, Analytic -- Research ,Chemistry - Abstract
The upper detection limit of polar ionophore-based ion-selective electrode membranes is predicted by utilizing the coextraction constant of dissociated electrolyte, the stability constant of the ionophore, and the membrane composition. The coextraction constant of dissociated electrolytes into the polar poly(vinyl chloride) membrane plasticized with o-nitrophenyl octyl ether (PVC-NPOE) is here measured by a novel approach. The sandwich membrane technique is utilized, with one membrane segment containing a lipophilic cation exchanger and the other containing an anion exchanger. This yields information about the coextraction constant and the free ion concentrations of the electrolyte in the two segments. Predictions correlate quantitatively with the upper detection limit observed for ion-selective electrodes based on the ionophores valinomycin, tert-butylcalix[4]arene tetraethyl ester, and calcimycin. The difficulties of the prediction of the upper detection limit for nonpolar poly(vinyl chloride) membranes plasticized with bis(2-ethylhexyl sebacate) (PVC-DOS) due to ion association are discussed in detail. A thermodynamic cycle experiment with a series of sandwich membranes shows that the principal processes governing the upper detection limit of PVC-DOS membranes are identical to those for the PVC-NPOE membranes. However, the stability of the ion pairs between the ionophore-metal ion complexes and the extracted anion are different from that of ion pairs formed between the same anion and the lipophilic anion exchanger. This makes it difficult to quantitatively predict the upper detection limit on the basis of simple apparent coextraction and complexation data alone. The approach reported herein is useful not only for mechanistic purposes but also to shed light onto the many cases where coextraction effects need to be understood but are not directly experimentally accessible.
- Published
- 2002
27. Coupled vectors resolution method for chemometric calibration with three-way data
- Author
-
Jian-Hui Jiang, Hai-Long Wu, Zeng-Ping Chen, and Ru-Qin Yu
- Subjects
Chemistry, Analytic -- Quantitative ,Calibration -- Research ,Chemistry - Abstract
A new second-order calibration procedure, the coupled vectors resolution (COVER) method, has been developed. The objective of the method is to seek a couple of vectors that minimize a least-squares criterion. With the knowledge indispensable for quantitation, the method yields direct solutions to various cases of second-order calibration. Moreover, it allows a statistically plausible way to make use of multisample information. In the case of multiple calibration samples, the method uses the calibration samples to resolve the profiles of the analytes in each order, and then calculates the concentrations of the analytes. This offers the advantage that unknown mixtures newly collected can be predicted in a direct manner. In the case of one calibration sample, the method provides an effective way to utilize the information of spectral profiles of the analytes. Results of simulated experiments and a real analytical example show that the proposed method produces acceptable performance in profile resolution and concentration estimation.
- Published
- 1999
28. Core–Shell–Shell Multifunctional Nanoplatform for Intracellular Tumor-Related mRNAs Imaging and Near-Infrared Light Triggered Photodynamic–Photothermal Synergistic Therapy
- Author
-
Wen-Jing Deng, Yao Cen, Ru-Qin Yu, Xia Chu, and Yuan Yang
- Subjects
congenital, hereditary, and neonatal diseases and abnormalities ,Indoles ,Cell Survival ,Infrared Rays ,Polymers ,education ,Nanoprobe ,Breast Neoplasms ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,health services administration ,Humans ,Photosensitizer ,RNA, Messenger ,Microscopy, Confocal ,Photosensitizing Agents ,Quenching (fluorescence) ,Singlet Oxygen ,Chemistry ,Phototherapy ,Photothermal therapy ,Silicon Dioxide ,021001 nanoscience & nanotechnology ,Photon upconversion ,0104 chemical sciences ,Methylene Blue ,Photochemotherapy ,MCF-7 Cells ,Nanoparticles ,Female ,DNA Probes ,0210 nano-technology ,Biosensor ,Intracellular ,Methylene blue - Abstract
A multifunctional nanoplatform, which generally integrates biosensing, imaging diagnosis, and therapeutic functions into a single nanoconstruct, has great important significance for biomedicine and nanoscience. Here, we developed a core–shell–shell multifunctional polydopamine (PDA) modified upconversion nanoplatform for intracellular tumor-related mRNAs detection and near-infrared (NIR) light triggered photodynamic and photothermal synergistic therapy (PDT–PTT). The nanoplatform was constructed by loading a silica shell on the hydrophobic upconversion nanoparticles (UCNPs) with hydrophilic photosensitizer methylene blue (MB) entrapped in it, and then modifying PDA shells through an in situ self-polymerization process, thus yielding a core–shell–shell nanoconstruct UCNP@SiO2–MB@PDA. By taking advantages of preferential binding properties of PDA for single-stranded DNA over double-stranded DNA and the excellent quenching property of PDA, a UCNP@SiO2–MB@PDA–hairpin DNA (hpDNA) nanoprobe was developed throug...
- Published
- 2017
29. In Situ Imaging of Individual mRNA Mutation in Single Cells Using Ligation-Mediated Branched Hybridization Chain Reaction (Ligation-bHCR)
- Author
-
Xiao-Li Zhang, Jian-Hui Jiang, Li-Juan Tang, Ru-Qin Yu, and Ying Tang
- Subjects
In situ ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,Ligases ,Nucleic acid thermodynamics ,Single-cell analysis ,Gene expression ,Tumor Cells, Cultured ,medicine ,Humans ,RNA, Messenger ,Genotyping ,In Situ Hybridization, Fluorescence ,Microscopy, Confocal ,medicine.diagnostic_test ,Chemistry ,Point mutation ,Optical Imaging ,Nucleic Acid Hybridization ,021001 nanoscience & nanotechnology ,Molecular biology ,0104 chemical sciences ,Mutation ,Mutation (genetic algorithm) ,Single-Cell Analysis ,0210 nano-technology ,HT29 Cells ,Fluorescence in situ hybridization - Abstract
Ultrasensitive and specific in situ imaging of gene expression is essential for molecular medicine and clinical theranostics. We develop a novel fluorescence in situ hybridization (FISH) strategy based on a new branched hybridization chain reaction (bHCR) for efficient signal amplification in the FISH assay and a ligase-mediated discrimination for specific mutation detection. To our knowledge, this is the first time that HCR has been realized for mutation detection in the FISH assay. In vitro assay shows that the ligation-bHCR strategy affords high specificity in discriminating single-nucleotide variation in mRNA, and it generates a highly branched polymeric product that confers more efficient amplification or better sensitivity than HCR. Imaging analysis reveals that ligation-bHCR generates highly bright spot-like signals for localization of individual mRNA molecules, and spot signals of different colors are highly specific in genotyping point mutation of individual mRNA. Moreover, this strategy is shown to have the potential for quantitative imaging of the expression of mRNA at the single-cell level. Therefore, this strategy may provide a new promising paradigm in developing highly sensitive and specific FISH methods for various diagnostic and research applications.
- Published
- 2017
30. Recombinant Fusion Streptavidin as a Scaffold for DNA Nanotetrads for Nucleic Acid Delivery and Telomerase Activity Imaging in Living Cells
- Author
-
Zhenkun Wu, Zhi-Mei Huang, Ru-Qin Yu, Chong-Hua Zhang, Jian-Hui Jiang, and Mei-Ya Lin
- Subjects
Streptavidin ,Telomerase ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,Nucleic acid thermodynamics ,Drug Delivery Systems ,Live cell imaging ,law ,Limit of Detection ,Nucleic Acids ,Humans ,Nuclear Export Signals ,010401 analytical chemistry ,Nucleic Acid Hybridization ,DNA ,Recombinant Proteins ,0104 chemical sciences ,Cell biology ,Molecular Imaging ,Nanostructures ,chemistry ,Biotinylation ,Recombinant DNA ,Nucleic acid ,Oligopeptides ,HeLa Cells - Abstract
Efficient platforms for intracellular delivery of nucleic acids are essential for biomedical imaging and gene regulation. We develop a recombinant fusion streptavidin as a novel protein scaffold for DNA nanotetrads for highly efficient nucleic acid delivery and telomerase activity imaging in living cells via cross-linking hybridization chain reaction (cHCR). The recombinant streptavidin protein is designed to fuse with multiple SV40 NLS (nuclear localization signal) and NES (nuclear export signal) domains and prepared through Escherichia coli expression. The recombinant NLS-SA protein allows facile assembly with four biotinylated DNA probes via high-affinity noncovalent interactions, forming a well-defined DNA tetrad nanostructure. The DNA nanotetrads are demonstrated to confer efficient cytosolic delivery of nucleic acid via a caveolar mediated endocytosis pathway, allowing efficient escape from lysosomal degradation. Moreover, the nanotetrads enable efficient cHCR assembly in response to telomerase in vitro and in cellulo, affording ultrasensitive detection and spatially resolved imaging for telomerase with a detection limit as low as 90 HeLa cells/mL. The fluorescence brightness obtained in live cell imaging is found to be dynamically correlated to telomerase activity and the inhibitor concentrations. Therefore, the proposed strategy may provide a highly efficient platform for nucleic acid delivery and imaging of biomarkers in living cells.
- Published
- 2019
31. Mitochondrion-Targeting Fluorescence Probe via Reduction Induced Charge Transfer for Fast Methionine Sulfoxide Reductases Imaging
- Author
-
Jian-Hui Jiang, Fenglin Wang, Mei-Hao Xiang, Hui Huang, Xian-Jun Liu, Zong-Xuan Tong, Chun-Xia Zhang, and Ru-Qin Yu
- Subjects
Fluorophore ,Time Factors ,010402 general chemistry ,01 natural sciences ,PC12 Cells ,Analytical Chemistry ,Electron Transport ,chemistry.chemical_compound ,Animals ,Humans ,Methylpyridinium ,Fluorescent Dyes ,010401 analytical chemistry ,Substrate (chemistry) ,Sulfoxide ,Electron transport chain ,Fluorescence ,0104 chemical sciences ,Mitochondria ,Molecular Imaging ,Rats ,chemistry ,Methionine Sulfoxide Reductases ,Biophysics ,Methionine sulfoxide reductase ,MSRA ,HeLa Cells - Abstract
Methionine sulfoxide reductases (Msrs) play essential roles in maintaining mitochondrial function and are recognized as potential therapeutic targets. However, current probes for Msrs fail to target mitochondria and exhibit a relatively slow response and limited sensitivity. Here we develop a novel turn-on fluorescence probe that facilitates imaging of mitochondrial Msrs in living cells. The probe is constructed by conjugating a methyl phenyl sulfoxide, a mimic Msrs substrate, to an electron-withdrawing hydrophobic cation, methylpyridinium. The probe of acceptor-acceptor structure is initially nonemissive. Msrs catalyzed reduction of sulfoxide to sulfide generated a fluorophore of distinct donor-acceptor structure. The probe is demonstrated to exhibit high sensitivity, fast response, and high selectivity toward MsrA in vitro. Furthermore, the probe is successfully introduced to detect and image Msrs in living cells with excellent mitochondrial-targeting capability. Moreover, the probe also reveals decreased Msrs activity in a cellular Parkinson's disease model. Our probe affords a powerful tool for detecting and visualizing mitochondrial Msrs in living cells.
- Published
- 2019
32. Label-Free and Multiplexed Quantification of microRNAs by Mass Spectrometry Based on Duplex-Specific-Nuclease-Assisted Recycling Amplification
- Author
-
Ru-Qin Yu, Sheng-Xian Li, Qing Liu, Zeng-Ping Chen, and Cai-Xia Shi
- Subjects
Detection limit ,Nuclease ,biology ,Chemistry ,010401 analytical chemistry ,Computational biology ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,Multiplexing ,Mass Spectrometry ,0104 chemical sciences ,Analytical Chemistry ,MicroRNAs ,Ribonucleases ,Duplex (building) ,Clinical diagnosis ,Cell Line, Tumor ,microRNA ,biology.protein ,Humans ,Nucleic Acid Amplification Techniques ,Label free ,HeLa Cells - Abstract
MicroRNAs (miRNAs) are important biomarker candidates for cancer screening and early detection research. Generally, miRNAs undergo synergistic adjustments in tumor cells. Herein, a mass-spectrometric method based on a duplex-specific-nuclease (DSN)-enzyme-assisted signal-amplification technique was proposed for label-free and multiplexed detection of multiple miRNAs, and applied to the quantification of three miRNAs (i.e., miRNA-141, miRNA-21, and let-7a) in samples of HeLa and MDA-MB231 cell extracts. Experimental results showed that the digestion modes of DSN against three different DNAs complementary to miRNA-141, miRNA-21, and let-7a in their DNA-miRNA heteroduplexes were quite different, verifying the multiplexed-detection capability of the proposed method. Moreover, an advanced calibration model was derived for the quantitative analysis of the complex mass-spectral data measured during the label-free and multiplexed detection of miRNA-141, miRNA-21, and let-7a by the proposed mass-spectrometric method. With the aid of the advanced calibration model, the proposed mass-spectrometric method achieved quite reliable quantitative results for miRNA-141, miRNA-21, and let-7a in samples of HeLa and MDA-MB231 cell extracts, with recovery rates within the range of 89.2 to 111.6%. The limits of detection (LODs) of the proposed mass-spectrometric method for miRNA-141, miRNA-21, and let-7a in standard samples were estimated to be 42, 41, and 95 pM, respectively. Therefore, it is reasonable to expect that the proposed mass-spectrometric method can be a competitive alternative for the label-free and multiplexed detection of multiple miRNAs in clinical diagnosis.
- Published
- 2018
33. Multivalent Self-Assembled DNA Polymer for Tumor-Targeted Delivery and Live Cell Imaging of Telomerase Activity
- Author
-
Ru-Qin Yu, Xueli Zhu, Hongyan Ye, Jian-Hui Jiang, and Jin-Wen Liu
- Subjects
Telomerase ,Polymers ,Aptamer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Fluorescence ,Analytical Chemistry ,Nucleic acid thermodynamics ,chemistry.chemical_compound ,Live cell imaging ,Limit of Detection ,Cell Line, Tumor ,Humans ,Enzyme Assays ,Fluorescent Dyes ,Chemistry ,Nucleic Acid Hybridization ,RNA-Binding Proteins ,DNA ,Aptamers, Nucleotide ,Carbocyanines ,021001 nanoscience & nanotechnology ,Phosphoproteins ,0104 chemical sciences ,Telomere ,Cell biology ,Cancer cell ,Primer (molecular biology) ,0210 nano-technology - Abstract
The efficient detection and in situ monitoring of telomerase activity is of great importance for cancer diagnosis and biomedical research. Here we report for the first time that the development of a novel multivalent self-assembled DNA polymer, constructed through telomerase primer sequence (ITS) triggered hybridization chain assembly using two functional hairpin probes (tumor-trageting aptamer modified H1 and signal probe modified H2), for sensitive detection and imaging of telomerase activity in living cells. After internalizing into the tumor cells by multivalent aptamer targeting, the ITS on DNA polymers can be elongated by intracellular telomerase to generate telomere repeat sequences that are complementary with the signal probe, which can proceed along the DNA polymers, and gradually light up the whole DNA polymers, leading to an enhanced fluorescence signal directly correlated with the activity of telomerase. Our results demonstrated that the developed DNA polymer show excellent performance for specifically detecting telomerase activity in cancer cells, dynamically monitoring the activity change of telomerase in response to telomerase-based drugs, and efficiently distinguishing cancer cells from normal cells. The proposed strategy may afford a valuable tool for the monitoring of telomerase activity in living cells and have great implications for biological and diagnostic applications.
- Published
- 2018
34. Label-Free Photonic Crystal-Based β-Lactamase Biosensor for β-Lactam Antibiotic and β-Lactamase Inhibitor
- Author
-
Zhaoyang Wu, Fubing Xiao, Yan Wu, Guoguo Li, Qianshan Chen, and Ru-Qin Yu
- Subjects
Stereochemistry ,medicine.drug_class ,Antibiotics ,Fresh Water ,Biosensing Techniques ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,Catalysis ,Hydrolysis ,chemistry.chemical_compound ,Bacillus cereus ,Limit of Detection ,medicine ,Clavulanic Acid ,Penicillin G ,Penicillinase ,Colloidal crystal ,Enzymes, Immobilized ,021001 nanoscience & nanotechnology ,Combinatorial chemistry ,Anti-Bacterial Agents ,0104 chemical sciences ,Penicillin ,chemistry ,Lactam ,beta-Lactamase Inhibitors ,0210 nano-technology ,Biosensor ,Water Pollutants, Chemical ,Penicilloic acid ,medicine.drug - Abstract
A simple, label-free, and visual photonic crystal-based β-lactamase biosensor was developed for β-lactam antibiotic and β-lactamase inhibitor in which the penicillinase (a β-lactamase) was immobilized on the pH-sensitive colloidal crystal hydrogel (CCH) film to form penicillinase colloidal crystal hydrogel (PCCH) biosensing film. The hydrolysis of penicillin G (a β-lactam antibiotic) can be catalyzed by penicillinase to produce penicilloic acid, leading to a pH decrease in the microenvironment of PCCH film, which causes the shrink of pH-sensitive CCH film and triggers a blue-shift of the diffraction wavelength. Upon the addition of β-lactamase inhibitor, the hydrolysis reaction is suppressed and no clear blue-shift is observed. The concentrations of β-lactam antibiotic and β-lactamase inhibitor can be sensitively evaluated by measuring the diffraction shifts. The minimum detectable concentrations for penicillin G and clavulanate potassium (a β-lactamase inhibitor) can reach 1 and 0.1 μM, respectively. Furthermore, the proposed method is highly reversible and selective, and it allows determination of penicillin G in fish pond water samples.
- Published
- 2016
35. Quench-Shield Ratiometric Upconversion Luminescence Nanoplatform for Biosensing
- Author
-
Xiao-Bing Zhang, Dailiang Zhang, Weihong Tan, Yuan Wu, Zhi-Ling Song, Yong-Xiang Wu, Ru-Qin Yu, Cui-Cui Zhang, and Jun-Bin Li
- Subjects
Luminescence ,Fluorophore ,Luminescent Measurements ,Surface Properties ,Upconversion luminescence ,Nanoparticle ,Nanotechnology ,Biosensing Techniques ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Tumor Cells, Cultured ,Rhodamine B ,Humans ,Particle Size ,Quenching ,Rhodamines ,Chemistry ,business.industry ,Mercury ,Hydrogen-Ion Concentration ,Fluoresceins ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Nanoparticles ,Optoelectronics ,0210 nano-technology ,business ,Biosensor ,HeLa Cells - Abstract
Upconversion nanoparticles (UCNPs) possess several unique features, but they suffer from surface quenching effects caused by the interaction between the UCNPs and fluorophore. Thus, the use of UCNPs for target-induced emission changes for biosensing and bioimaging has been challenging. In this work, fluorophore and UCNPs are effectively separated by a silica transition layer with a thickness of about 4 nm to diminish the surface quenching effect of the UCNPs, allowing a universal and efficient luminescence resonance energy transfer (LRET) ratiometric upconversion luminescence nanoplatform for biosensing applications. A pH-sensitive fluorescein derivative and Hg(2+)-sensitive rhodamine B were chosen as fluoroionphores to construct the LRET nanoprobes. Both showed satisfactory target-triggered ratiometric upconversion luminescence responses in both solution and live cells, indicating that this strategy may find wide applications in the design of nanoprobes for various biorelated targets.
- Published
- 2016
36. Activatable Fluorescence Probe via Self-Immolative Intramolecular Cyclization for Histone Deacetylase Imaging in Live Cells and Tissues
- Author
-
Jian-Hui Jiang, Zong-Xuan Tong, Mei-Hao Xiang, Fenglin Wang, Feng Liu, Wen Chen, Xian-Jun Liu, Feng-Yan Luo, and Ru-Qin Yu
- Subjects
Fluorophore ,Uterine Cervical Neoplasms ,010402 general chemistry ,01 natural sciences ,Histone Deacetylases ,Analytical Chemistry ,Small Molecule Libraries ,chemistry.chemical_compound ,Transcriptional regulation ,Humans ,Fluorescent Dyes ,Aminocaproates ,Aldehydes ,biology ,Molecular Structure ,010405 organic chemistry ,Chemistry ,Optical Imaging ,Fluorescence ,In vitro ,0104 chemical sciences ,Histone ,Acetylation ,Cyclization ,biology.protein ,Biophysics ,Carcinoma, Squamous Cell ,Female ,Histone deacetylase ,Linker ,HeLa Cells - Abstract
Histone deacetylases (HDACs) play essential roles in transcription regulation and are valuable theranostic targets. However, there are no activatable fluorescent probes for imaging of HDAC activity in live cells. Here, we develop for the first time a novel activatable two-photon fluorescence probe that enables in situ imaging of HDAC activity in living cells and tissues. The probe is designed by conjugating an acetyl-lysine mimic substrate to a masked aldehyde-containing fluorophore via a cyanoester linker. Upon deacetylation by HDAC, the probe undergoes a rapid self-immolative intramolecular cyclization reaction, producing a cyanohydrin intermediate that is spontaneously rapidly decomposed into the highly fluorescent aldehyde-containing two-photon fluorophore. The probe is shown to exhibit high sensitivity, high specificity, and fast response for HDAC detection in vitro. Imaging studies reveal that the probe is able to directly visualize and monitor HDAC activity in living cells. Moreover, the probe is demonstrated to have the capability of two-photon imaging of HDAC activity in deep tissue slices up to 130 μm. This activatable fluorescent probe affords a useful tool for evaluating HDAC activity and screening HDAC-targeting drugs in both live cell and tissue assays.
- Published
- 2018
37. Tumor-Targeted Graphitic Carbon Nitride Nanoassembly for Activatable Two-Photon Fluorescence Imaging
- Author
-
Zheng Li, Jin-Wen Liu, Ru-Qin Yu, Jian-Hui Jiang, Chong-Hua Zhang, Yu-Min Wang, and Lu-Ying Duan
- Subjects
Chemistry ,Graphitic carbon nitride ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Two photon fluorescence ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Analytical Chemistry ,Tumor targeted ,chemistry.chemical_compound ,0210 nano-technology - Abstract
Unique physicochemical characteristics of graphitic carbon nitride (g-CN) nanosheets suit them to be a useful tool for two-photon fluorescence bioimaging. Current g-CN nanosheets based imaging probes typically use the "always-on" design strategies, which may suffer from increased fluorescence background and limited contrast. To advance corresponding applications, g-CN nanosheets based activatable two-photon fluorescence probes remain to be explored. For the first time, we developed an activatable two-photon fluorescence probe, constructed from a nanoassembly of g-CN nanosheets and hyaluronic acid (HA)-gold nanoparticles (HA-AuNPs), for detection and imaging of hyaluronidase (HAase) in cancer cells. The deliberately introduced HA in our design not only functions as the buffering layer for stabilizing AuNPs and inducing corresponding self-assembly on g-CN nanosheets but also as a pilot for targeting HA receptors overexpressed on cancer cell surfaces. Our results show that the developed nanoassembly enables specific detection and activatable imaging of HAase in cancer cells and deep tissues, with superb signal-to-background ratio and high sensitivity. This nanoassembly can afford a promising platform for highly specific and sensitive imaging of HAase and for related cancer diagnosis.
- Published
- 2018
38. Conductive Polymer Coated Scaffold to Integrate 3D Cell Culture with Electrochemical Sensing
- Author
-
Zhang, Hai-Wei, primary, Hu, Xue-Bo, additional, Qin, Yu, additional, Jin, Zi-He, additional, Zhang, Xin-Wei, additional, Liu, Yan-Ling, additional, and Huang, Wei-Hua, additional
- Published
- 2019
- Full Text
- View/download PDF
39. Flexible Electrochemical Urea Sensor Based on Surface Molecularly Imprinted Nanotubes for Detection of Human Sweat
- Author
-
Liu, Yan-Ling, primary, Liu, Rong, additional, Qin, Yu, additional, Qiu, Quan-Fa, additional, Chen, Zhen, additional, Cheng, Shi-Bo, additional, and Huang, Wei-Hua, additional
- Published
- 2018
- Full Text
- View/download PDF
40. Activatable Two-Photon Fluorescence Nanoprobe for Bioimaging of Glutathione in Living Cells and Tissues
- Author
-
Hong-Min Meng, Ru-Qin Yu, Xiao-Bing Zhang, Weihong Tan, Zhen Jin, Yifan Lv, and Chan Yang
- Subjects
Photons ,Fluorescence-lifetime imaging microscopy ,Membrane permeability ,Static Electricity ,Nanoprobe ,Nanoparticle ,Glutathione ,Mesoporous silica ,Two photon fluorescence ,Fluorescence ,Analytical Chemistry ,chemistry.chemical_compound ,Microscopy, Electron, Transmission ,Biochemistry ,chemistry ,Humans ,Fluorescent Dyes ,HeLa Cells - Abstract
Glutathione (GSH) serves vital cellular biological functions, and its abnormal levels are associated with many diseases. To better understand its physiological and pathological functions, efficient methods for monitoring of GSH in living systems are desired. Although quite a few small molecule-based and nanomaterial-based one photon fluorescence probes have been reported for GSH, two-photon (TP) probes, especially nanoprobes with good membrane permeability, are more favorable for bioimaging applications, since TP fluorescence imaging can provide improved spatial localization and increased imaging depth. In this work, we for the first time reported a "turn-on" TP fluorescence nanoprobe for efficient detection of GSH in aqueous solutions and TP excited fluorescence imaging of GSH in living cells and tissues. The nanoprobe consists of two-photon mesoporous silica nanoparticles (TP-MSNs) with a large TP excitation action cross-section (Φδ) value of 103 GM and MnO2 nanosheets, which show intense and broad optical absorption and could act as efficient quenchers for TP fluorescence. In the sensing system, the negatively charged MnO2 nanosheets are adsorbed on the positively charged MSNs through electrostatic interaction, resulting in efficient quenching of their fluorescence, with very low background fluorescence observed. The addition of GSH could reduce MnO2 into Mn(2+), lead to the decomposition of the MnO2 nanosheets, and thereby result in remarkable enhancement of both one photon and TP excited fluorescence of the nanosystem. The nanoprobe shows a highly sensitive response to GSH in aqueous solutions, with a detection limit of 200 nM achieved. It also exhibits a high selectivity toward GSH relative to other biomolecules and electrolytes, with good membrane permeability and excellent biocompatibility. The nanoprobe was successfully applied in monitoring the change of the intracellular GSH in living cells and tissues via TP fluorescence imaging, demonstrating its value of practical application in biological systems.
- Published
- 2014
41. Generalized Ratiometric Indicator Based Surface-Enhanced Raman Spectroscopy for the Detection of Cd2+ in Environmental Water Samples
- Author
-
Yao Chen, Si-Yu Long, Ru-Qin Yu, and Zeng-Ping Chen
- Subjects
Detection limit ,Trithiocyanuric acid ,Chemistry ,Analytical chemistry ,Metal Nanoparticles ,Nanoparticle ,Surface-enhanced Raman spectroscopy ,Spectrum Analysis, Raman ,Analytical Chemistry ,law.invention ,symbols.namesake ,Binding ability ,Environmental water ,Limit of Detection ,law ,symbols ,Gold ,Raman spectroscopy ,Atomic absorption spectroscopy ,Water Pollutants, Chemical ,Cadmium - Abstract
The concept of generalized ratiometric indicator based surface-enhanced Raman spectroscopy was first introduced and successfully implemented in the detection of Cd(2+) in environmental water samples using Au nanoparticles (AuNPs) modified by trithiocyanuric acid (TMT). Without the use of any internal standard, the proposed method achieved accurate concentration predictions for Cd(2+) in environmental water samples with recoveries in the ranges of 91.8-108.1%, comparable to the corresponding values obtained by atomic absorption spectroscopy. The limit of detection and limit of quantification were estimated to be 2.9 and 8.7 nM, respectively. More importantly, other species present in water samples which cannot react with TMT and have weaker binding ability to AuNPs than TMT do not interfere with the quantification of Cd(2+). Therefore, it is expected that the combination of the generalized ratiometric indicator based surface-enhanced Raman spectroscopy with the proposed AuNP-TMT probing system can be a competitive alternative for the primary screening of Cd(2+) pollution.
- Published
- 2014
42. Bispyrene–Fluorescein Hybrid Based FRET Cassette: A Convenient Platform toward Ratiometric Time-Resolved Probe for Bioanalytical Applications
- Author
-
Hao Liang, Yong-Xiang Wu, Guo-Jiang Mao, Xiao-Bing Zhang, Liyi Zhou, Jun-Bin Li, Ru-Qin Yu, Weihong Tan, and Cui-Cui Zhang
- Subjects
Pyrenes ,Molecular Structure ,Chemistry ,Nanotechnology ,Excimer ,Fluorescence ,Analytical Chemistry ,Autofluorescence ,symbols.namesake ,chemistry.chemical_compound ,Förster resonance energy transfer ,Stokes shift ,Fluorescence Resonance Energy Transfer ,symbols ,Humans ,Pyrene ,Biological Assay ,Fluorescein ,Molecular probe ,Biosensor ,Fluorescent Dyes ,HeLa Cells - Abstract
Pyrene excimer possesses a large Stokes shift and long fluorescence lifetime and has been widely applied in developing time-resolved biosensing systems to solve the autofluorescence interference problems in biological samples. However, only a few of pyrene excimer-based small molecular probes have been reported so far. Ratiometric probes, on the other hand, can eliminate interferences from environmental factors such as instrumental efficiency and environmental conditions by a built-in correction of the dual emission bands but are ineffective for endogenous autofluorescence in biosystems. In this work, by combining the advantages of time-resolved fluorescence technique with ratiometric probe, we reported a bispyrene-fluorescein hybrid FRET cassette (PF) as a novel ratiometric time-resolved sensing platform for bioanalytical applications, with pH chosen as a biorelated target. The probe PF showed a fast, highly selective, and reversible ratiometric fluorescence response to pH in a wide range from 3.0 to 10.0 in buffered solution. By employing time-resolved fluorescence technique, the pH-induced fluorescence signal of probe PF can be well-discriminated from biological autofluorescence background, which enables us to detect pH in a range of 4.0-8.0 in cell media within a few seconds. It has also been preliminarily applied for ratiometric quantitative monitoring of pH changes in living cells with satisfying results. Since many fluorescein-based fluorescence probes have been developed, our strategy might find wide applications in design ratiometric time-resolved probes for detection of various biorelated targets.
- Published
- 2014
43. Novel Aptasensor Platform Based on Ratiometric Surface-Enhanced Raman Spectroscopy
- Author
-
Fubing Xiao, Yan Wu, Ru-Qin Yu, and Zhaoyang Wu
- Subjects
Aptamer ,technology, industry, and agriculture ,Analytical chemistry ,Nanoparticle ,02 engineering and technology ,Surface-enhanced Raman spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Complementary DNA ,symbols ,Biophysics ,0210 nano-technology ,Raman spectroscopy ,Adenosine triphosphate ,DNA ,Raman scattering - Abstract
A novel aptasensor platform has been developed for quantitative detection of adenosine triphosphate (ATP) based on a ratiometric surface-enhanced Raman scattering (SERS) strategy. The thiolated 3'-Rox-labeled complementary DNA (cDNA) is first immobilized on the gold nanoparticle (AuNP) surface and then hybridizes with the 3'-Cy5-labeled ATP-binding aptamer probe (Cy5-aptamer) to form a rigid double-stranded DNA (dsDNA), in which the Cy5 and Rox Raman labels are used to produce the ratiometric Raman signals. In the presence of ATP, the Cy5-aptamer is triggered the switching of aptamer to form the aptamer-ATP complex, leading to the dissociation of dsDNA, and the cDNA is then formed a hairpin structure. As a result, the Rox labels are close to the AuNP surface while the Cy5 labels are away from. Therefore, the intensity of SERS signal from Rox labels increases while that from Cy5 labels decreases. The results show that the ratio between the Raman intensities of Rox labels and Cy5 labels is well linear with the ATP concentrations in the range from 0.1 to 100 nM, and the limit of detection reaches 20 pM, which is much lower than that of other methods for ATP detection and is also lower than that of SERS aptasensor for ATP detection. The proposed strategy provides a new reliable platform for the construction of SERS biosensing methods and has great potential to be a general method for other aptamer systems.
- Published
- 2017
44. Peptide-Templated Gold Nanocluster Beacon as a Sensitive, Label-Free Sensor for Protein Post-translational Modification Enzymes
- Author
-
Ru-Qin Yu, Li-Juan Tang, Jian-Hui Jiang, Qian Wen, and Yi Gu
- Subjects
chemistry.chemical_classification ,Chemistry ,Histone Deacetylase 1 ,Peptide ,Biosensing Techniques ,Cyclic AMP-Dependent Protein Kinases ,Fluorescence ,Nanocomposites ,Analytical Chemistry ,Nanoclusters ,Spectrometry, Fluorescence ,Enzyme ,Biochemistry ,Posttranslational modification ,Animals ,Cattle ,Gold ,Peptides ,Protein kinase A ,Protein Processing, Post-Translational ,Biosensor ,Fluorescent Dyes ,Label free - Abstract
Protein post-translational modifications (PTMs), which are chemical modifications and most often regulated by enzymes, play key roles in functional proteomics. Detection of PTM enzymes, thus, is critical in the study of cell functioning and development of diagnostic and therapeutic tools. Herein, we develop a simple peptide-templated method to direct rapid synthesis of highly fluorescent gold nanoclusters (AuNCs) and interrogate the effect of enzymatic modifications on their luminescence. A new finding is that enzymes are able to exert chemical modifications on the peptide-templated AuNCs and quench their fluorescence, which furnishes the development of a real-time and label-free sensing strategy for PTM enzymes. Two PTM enzymes, histone deacetylase 1 and protein kinase A, have been employed to demonstrate the feasibility of this enzyme-responsive fluorescent nanocluster beacon. The results reveal that the AuNCs' fluorescence can be dynamically decreased with increasing concentration of the enzymes, and subpicomolar detection limits are readily achieved for both enzymes. The developed strategy can thus offer a useful, label-free biosensor platform for the detection of protein-modifying enzymes and their inhibitors in biomedical applications.
- Published
- 2013
45. Target-Triggered Cyclic Assembly of DNA–Protein Hybrid Nanowires for Dual-Amplified Fluorescence Anisotropy Assay of Small Molecules
- Author
-
Ru-Qin Yu, Guo-Li Shen, Li-Ping Kang, Bin Yang, Xiao-Bing Zhang, and Weihong Tan
- Subjects
Detection limit ,Streptavidin ,Molar mass ,Base Sequence ,Nanowires ,Chemistry ,Aptamer ,Molecular Sequence Data ,Oligonucleotides ,Analytical chemistry ,Fluorescence Polarization ,DNA ,Small molecule ,Analytical Chemistry ,chemistry.chemical_compound ,Gene Targeting ,Biophysics ,Humans ,A-DNA ,Fluorescence anisotropy - Abstract
Aptamer-based fluorescence anisotropy (FA) assays have attracted great interest in recent years. However, a key factor that determines FA value is molar mass, thus limiting the utility of this assay for the detection of small molecules. To solve this problem, streptavidin, as a molar mass amplifier, was used in a hybridization chain reaction (HCR) to construct a target-triggered cyclic assembly of DNA-protein hybrid nanowires for highly sensitive detection of small molecules by fluorescence anisotropy. In this assay, one blocking DNA strand is released by target-aptamer recognition. The DNA then serves as an initiator to trigger enzyme-free autonomous cross-opening of hairpin probes via HCR to form a DNA nanowire for further assembly of streptavidin. Using adenosine triphosphate (ATP) as the small molecule target, this novel dual-amplified, aptamer-based FA assay affords high sensitivity with a detection limit of 100 nM. This limit of detection (LOD) is much lower than that of the disassembly approach without HCR amplification or the assembly strategy without streptavidin. In contrast to the previous turn-off disassembly approaches based on nonspecific interactions between the aptamer probe and amplification moieties, the proposed aptamer-based FA assay method exhibits a turn-on response to ATP, which can increase sensing reliability and reduce the risk of false hits. Moreover, because of its resistance to environmental interferences, this FA assay has been successfully applied for direct detection of 0.5 μM ATP in complex biological samples, including cell media, human urine, and human serum, demonstrating its practicality in real complex biological systems.
- Published
- 2013
46. Fluorescence Lifetime-Resolved Ion-Selective Nanospheres for Simultaneous Imaging of Calcium Ion in Mitochondria and Lysosomes
- Author
-
Zhou, Shuai, primary, Peng, Xiao, additional, Xu, Haiyan, additional, Qin, Yu, additional, Jiang, Dechen, additional, Qu, Junle, additional, and Chen, Hong-Yuan, additional
- Published
- 2018
- Full Text
- View/download PDF
47. Stretchable and Photocatalytically Renewable Electrochemical Sensor Based on Sandwich Nanonetworks for Real-Time Monitoring of Cells
- Author
-
Wang, Ya-Wen, primary, Liu, Yan-Ling, additional, Xu, Jia-Quan, additional, Qin, Yu, additional, and Huang, Wei-Hua, additional
- Published
- 2018
- Full Text
- View/download PDF
48. Biomimetic Graphene-Based 3D Scaffold for Long-Term Cell Culture and Real-Time Electrochemical Monitoring
- Author
-
Hu, Xue-Bo, primary, Liu, Yan-Ling, additional, Wang, Wen-Jie, additional, Zhang, Hai-Wei, additional, Qin, Yu, additional, Guo, Shan, additional, Zhang, Xin-Wei, additional, Fu, Lei, additional, and Huang, Wei-Hua, additional
- Published
- 2018
- Full Text
- View/download PDF
49. Cooperative Amplification-Based Electrochemical Sensor for the Zeptomole Detection of Nucleic Acids
- Author
-
Ru-Qin Yu, Li Qiu, Zai-Sheng Wu, Liping Qiu, and Guo-Li Shen
- Subjects
Nucleic acid quantitation ,biology ,Chemistry ,EcoRI ,Analytical chemistry ,Metal Nanoparticles ,Biosensing Techniques ,Electrochemical Techniques ,Combinatorial chemistry ,Analytical Chemistry ,Electrochemical gas sensor ,Restriction site ,chemistry.chemical_compound ,Biotin ,Colloidal gold ,Nucleic Acids ,biology.protein ,Nucleic acid ,DNA - Abstract
In this work, we developed a multiple-amplification-based electrochemical sensor for ultrasensitive detection of nucleic acids using a disease-related sequence of the p53 gene as the model target. A capture probe (CP) with a hairpin structure is immobilized on the electrode surface via thiol-gold bonding, while its stem is designed to contain a restriction site for EcoRI. In the absence of target DNA, the probe keeps a closed conformation and forms a cleavable region. After treatment with EcoRI, the target binding portion (loop) plus the biotin tag can be peeled off, suppressing the background current. In contrast, the CP is opened by the target hybridization, deforming the restriction site and forcing the biotin tag away from the electrode. On the basis of the biotin-streptavidin complexation, gold nanoparticles (GNPs) modified with a large number of ferrocene-signaling probes (Fc-SPs) are captured by the resulting interface, producing an amplified electrochemical signal due to the GNP-based enrichment of redox-active moieties. Furthermore, Fc tags can be dragged in close proximity to the electrode surface via hybridization between the signaling probes and the CP residues after EcoRI treatment, facilitating interfacial electron transfer and further enhancing the signal. With combination of these factors, the present system is demonstrated to achieve an ultrahigh sensitivity of zeptomole level and a wide dynamic response range of over 7 orders of magnitude.
- Published
- 2013
50. Versatile DNAzyme-Based Amplified Biosensing Platforms for Nucleic Acid, Protein, and Enzyme Activity Detection
- Author
-
Bin Yang, Xiao-Bing Zhang, Ting Fu, Xu-Hua Zhao, Weihong Tan, Rong Hu, Ru-Qin Yu, and Liang Gong
- Subjects
Deoxyribozyme ,Nanotechnology ,Biosensing Techniques ,Cleavage (embryo) ,Cell Line ,Analytical Chemistry ,chemistry.chemical_compound ,Limit of Detection ,Escherichia coli ,Animals ,Humans ,DNA Modification Methylases ,Enzyme Assays ,chemistry.chemical_classification ,biology ,Biomolecule ,Proteins ,DNA ,DNA, Catalytic ,Enzyme assay ,Highly sensitive ,chemistry ,biology.protein ,Nucleic acid ,Biosensor - Abstract
DNAzymes have been widely applied as signal amplifiers for enzyme-free and highly sensitive detection of DNA. A few of them have also been employed for amplified detection of other biomolecules via a target-triggered assembly of split or mutated DNAzyme strategy. However, most of these designs adopt Mg(2+)-dependent DNAzyme as the catalytic unit, which suffered from low catalytic cleavage activity. Meanwhile, some DNAzymes with high catalytic activity are not suitable for these designs because the slight modification of the catalytic core might results in remarkably decreased or even no catalytic activity of these DNAzymes. On the basis of DNAzyme topological effect or the terminal protection of small-molecule-linked DNA, we developed two versatile sensing platforms for amplified detection of different biotargets. Since no modification is necessary for the catalytic core of the DNAzyme in these designs, they can employ any DNAzyme with high catalytic activity as amplified unit, which affords a high amplified efficiency for the sensing platform. A catalytic and molecular beacon design was further employed to realize the true enzymatic multiple turnover of DNAzyme. These designs together allow a high sensitivity for the biotargets, resulting in a detection limit of 20 pM, 0.2 U/mL, and 1 ng/mL for target DNA, DNA adenine methylation methyltransferase (Dam MTase), and streptavidin, respectively, much lower than previously reported biosensors. In addition, the proposed sensing strategy is versatile. By conjugating with various recognition units, it can be employed to detect a wide range of biotargets, varying from nucleic acids to proteins with high sensitivity.
- Published
- 2013
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.