15 results on '"Gooding, J. Justin"'
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2. The use of a personal glucose meter for detecting procalcitonin through glucose encapsulated within liposomes.
- Author
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Alshawawreh, Fida'a, Lisi, Fabio, Ariotti, Nicholas, Bakthavathsalam, Padmavathy, Benedetti, Tania, Tilley, Richard D., and Gooding, J. Justin
- Subjects
CALCITONIN ,GLUCOSE ,C-reactive protein ,TRITON X-100 ,SERUM albumin ,BLOOD proteins - Abstract
Herein, a glucose meter-based immunosensing platform is developed that allows the quantification of procalcitonin (PCT) in whole blood samples. PCT is a biomarker for sepsis and its early detection would improve the safety of the patient, as the diagnostic process will be easier and faster. The method employs liposomes with encapsulated glucose as a signal generation tag, which are then used in a sandwich immunoassay by conjugating an antibody to the liposome. The optimal liposomes' size and concentration of encapsulated glucose is determined experimentally to be 200 nm and 27.8 mM, respectively. Upon the addition of a surfactant (Triton X-100), the glucose is released and a signal is detected with a personal glucose meter (PGM). This signal is directly proportional to the concentration of the PCT in the sample. The dynamic range of the assay developed was 0.153–15.38 nM, and could allow the detection of PCT as low as 0.15 nM. The assay showed a high selectivity toward PCT against other proteins such as C-reactive protein and human serum albumin and good reproducibility. This assay was able to quantitatively determine the amount of PCT in whole blood samples at clinically-relevant concentrations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
3. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.
- Author
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Dumlao, Morphy C., Jeffress, Laura E., Gooding, J. Justin, and Donald, William A.
- Subjects
SOLID phase extraction ,LOW temperatures ,INDUCTIVELY coupled plasma mass spectrometry ,CHEMICAL warfare ,MIXTURE analysis ,PHOSPHATES analysis - Abstract
Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO
4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the ion source is compact, can be powered with a 10 V battery, and is tolerant of complex mixtures. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
4. Carbon quantum dots directly generated from electrochemical oxidation of graphite electrodes in alkaline alcohols and the applications for specific ferric ion detection and cell imaging.
- Author
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Liu, Mengli, Xu, Yuanhong, Niu, Fushuang, Gooding, J. Justin, and Liu, Jingquan
- Subjects
QUANTUM dots ,GRAPHITE ,CARBON electrodes ,OXIDATION ,ELECTROCHEMICAL research ,BIOCOMPATIBILITY - Abstract
Carbon quantum dots (CQDs) are attracting tremendous interest owing to their low toxicity, water dispersibility, biocompatibility, optical properties and wide applicability. Herein, CQDs with an average diameter of (4.0 ± 0.2) nm and high crystallinity were produced simply from the electrochemical oxidation of a graphite electrode in alkaline alcohols. The as-formed CQDs dispersion was colourless but the dispersion gradually changed to bright yellow when stored in ambient conditions. Based on UV-Vis absorption, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HRTEM), this colour change appeared to be due to oxygenation of surface species over time. Furthermore, the CQDs were used in specific and sensitive detection of ferric ion (Fe
3+ ) with broad linear ranges of 10–200 μM with a low limit of detection of 1.8 μM (S/N = 3). The application of the CQDs for Fe3+ detection in tap water was demonstrated and the possible mechanism was also discussed. Finally, based on their good characteristics of low cytotoxicity and excellent biocompatibility, the CQDs were successfully applied to cell imaging. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
5. Functionalised porous silicon as a biosensor: emphasis on monitoring cells in vivo and in vitro.
- Author
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Gupta, Bakul, Zhu, Ying, Guan, Bin, Reece, Peter J., and Gooding, J. Justin
- Subjects
POROUS silicon ,BIOSENSORS ,BIOMOLECULES ,PHOTONICS ,MICROFABRICATION - Abstract
Porous silicon photonics is the ideal platform for high sensitivity, high selectivity monitoring of biological molecules in a complex fluidic environment. The potential of this technology was identified almost 15 years ago, however, it has taken considerable advances in porous silicon surface chemistry, photonics, and micro-fabrication to create truly effective devices that can provide new insights into the behaviour of biological systems. In this review we provide a critical assessment of the development of porous silicon optical biosensors from the early demonstrations of affinity based sensing to the current trends in monitoring single cell activity and perspectives in the use of photonic microparticles for biomedical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
6. Application of N-PLS calibration to the simultaneous determination of Cu2, Cd2and Pb2using peptide modified electrochemical sensors
- Author
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Chow, Edith, Ebrahimi, Diako, Gooding, J. Justin, and Hibbert, D. Brynn
- Abstract
The simultaneous determination of Cu2, Cd2and Pb2is demonstrated at four modified gold electrodes using N-PLS calibration. Three of the electrodes were modified with the peptides Gly-Gly-His, γ-Glu-Cys Gly and human angiotensin I which were covalently attached to thioctic acid self-assembled monolayers and the fourth electrode was modified with thioctic acid only. Voltammetry at the modified electrodes in the presence of the three metal ions revealed one peak due to the reduction of copper and another due to the overlapping peaks of cadmium and lead which made quantification using conventional methods difficult. N-PLS was used to calibrate and predict trace concentrations (100 nM to 10 µM) of mixtures of Cu2, Cd2and Pb2.
- Published
- 2006
- Full Text
- View/download PDF
7. Voltammetric detection of cadmium ions at glutathione-modified gold electrodes
- Author
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Chow, Edith, Hibbert, D. Brynn, and Gooding, J. Justin
- Abstract
An electrochemical sensor for the detection of cadmium ions is described using immobilized glutathione as a selective ligand. First, a self-assembled monolayer of 3-mercaptopropionic acid MPA was formed on a gold electrode. The carboxyl terminus then allowed attachment of glutathione GSH viacarbodiimide coupling to give the MPA–GSH modified electrode. A cadmium ion forms a complex with glutathione viathe free sulfhydryl group and also to the carboxyl groups. The complexed ion is reduced by linear and Osteryoung square wave voltammetry with a detection limit of 5 nM. The effect of the kinetics of accumulation of cadmium on the measured current was investigated and modeled. Increasing the temperature of accumulation and electrochemical analysis caused an increase in the voltammetric peak of approximately 4 per °C around room temperature. The modified electrode could be regenerated, being stable for more than 16 repeated uses and more than two weeks if used once a day. Some interference from Pb2and Cu2was observed but the effects of Zn2, Ni2, Cr3and Ba2were insignificant.
- Published
- 2005
- Full Text
- View/download PDF
8. Exploring the use of the tripeptide GlyGlyHis as a selective recognition element for the fabrication of electrochemical copper sensors
- Author
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Yang, Wenrong, Chow, Edith, Willett, Gary. D., Hibbert, D. Brynn, and Gooding, J. Justin
- Abstract
The modification of electrodes with the tripeptide GlyGlyHis for the detection of copper in water samples is described in detail. The tripeptide modified electrode was prepared by first self-assembling 3-mercaptopropionic acid (MPA) onto the gold electrode followed by covalent attachment of the tripeptide to the self-assembled monolayer using carbodiimide coupling. The electrodes were characterized using electrochemistry, a newly developed mass-spectrometry method and quantum mechanical calculations. The mass spectrometry confirmed the modification to proceed as expected with peptide bonds formed between the carboxylic acids of the MPA and the terminal amine of the peptide. Electrochemical measurements indicated that approximately half the MPA molecules in a SAM are modified with the peptide. The peptide modified electrodes exhibited high sensitivity to copper which is attributed to the stable 4N coordinate complex the peptide formed around the metal ion to give copper the preferred tetragonal coordination. The formation of a 4 coordinate complex was predicted using quantum mechanical calculation and confirmed using mass spectrometry. The adsorption of the copper to the peptide modified electrode was consistent with a Langmuir isotherm with a binding constant of (8.1 ± 0.4) 10
10 M−1 at 25 °C.- Published
- 2003
9. Exploring the use of the tripeptide Gly–Gly–His as a selective recognition element for the fabrication of electrochemical copper sensors
- Author
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Yang, Wenrong, Chow, Edith, Willett, Gary. D., Hibbert, D. Brynn, and Gooding, J. Justin
- Abstract
The modification of electrodes with the tripeptide Gly–Gly–His for the detection of copper in water samples is described in detail. The tripeptide modified electrode was prepared by first self-assembling 3-mercaptopropionic acid (MPA) onto the gold electrode followed by covalent attachment of the tripeptide to the self-assembled monolayer using carbodiimide coupling. The electrodes were characterized using electrochemistry, a newly developed mass-spectrometry method and quantum mechanical calculations. The mass spectrometry confirmed the modification to proceed as expected with peptide bonds formed between the carboxylic acids of the MPA and the terminal amine of the peptide. Electrochemical measurements indicated that approximately half the MPA molecules in a SAM are modified with the peptide. The peptide modified electrodes exhibited high sensitivity to copper which is attributed to the stable 4N coordinate complex the peptide formed around the metal ion to give copper the preferred tetragonal coordination. The formation of a 4 coordinate complex was predicted using quantum mechanical calculation and confirmed using mass spectrometry. The adsorption of the copper to the peptide modified electrode was consistent with a Langmuir isotherm with a binding constant of (8.1 ± 0.4) 1010M−1at 25 °C.
- Published
- 2003
- Full Text
- View/download PDF
10. Redox voltammetry of sub-parts per billion levels of Cu2+ at polyaspartate-modified gold electrodes
- Author
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Yang, Wenrong, Gooding, J. Justin, and Hibbert, D. Brynn
- Abstract
An electrochemical sensor for the detection of Cu
2+ is reported which incorporates poly-l-aspartic acid (PLAsp) with 3296 aspartate units as a selective ligand for the metal ion. PLAsp is covalently attached to a gold electrode modified with a monolayer of 3-mercaptopropionic acid using carbodiimide coupling via an N-hydroxysuccinimide (NHS) ester intermediate. The acid side groups and deprotonated peptide nitrogens on two aspartate moieties are thought to be primarily responsible for chelation of Cu2+ , which remains bound when reduced to Cu+ . A consequence of the multiple binding points that are available with a polypeptide is the low detection limit. The lowest concentration detected was 3 nM (0.2 ppb) achieved with Osteryoung square wave voltammetry. This detection limit compares favourably with that of ICP-OES and previously reported cysteine-modified electrodes. Analysis of tap and lake water samples using the PLAsp-modified electrode agreed well with ICP-OES analysis of the same samples.- Published
- 2001
11. Multifunctional modified silver nanoparticles as ion and pH sensors in aqueous solution.
- Author
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Chen X, Cheng X, and Gooding JJ
- Subjects
- Copper analysis, Cysteamine chemistry, Ferric Compounds analysis, Hydrogen-Ion Concentration, Lead analysis, Ions chemistry, Metal Nanoparticles chemistry, Metals, Heavy analysis, Silver chemistry, Water chemistry
- Abstract
Silver nanoparticles capped with mercaptoacetic acid and 2-aminoethanethiol short-chain alkanethiols were prepared by a one-step method in aqueous solution for monitoring pH and a range of heavy metal ions. The mode of transduction is optical, based on the change in aggregation of the nanoparticles in solution. Because of the different ionic interactions between the modified nanoparticles, these nanoparticle sensors can rapidly detect Pb(2+), Cu(2+) and Fe(2+), with detection limits as low as 1 × 10(-5) M, 5 × 10(-7) M and 5 × 10(-5) M respectively, as well as having the ability to detect Cu(2+) ions from Pb(2+) and Fe(2+). Furthermore, the same functionalised nanoparticles are also sensitive to pH; exhibiting a good linear dynamic response between pH 1 and 10.
- Published
- 2012
- Full Text
- View/download PDF
12. Development of an electrochemical immunosensor for the detection of HbA1c in serum.
- Author
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Liu G, Khor SM, Iyengar SG, and Gooding JJ
- Subjects
- Diazonium Compounds, Electrochemistry methods, Electrodes, Ferrous Compounds metabolism, Glycated Hemoglobin immunology, Immunoassay methods, Immunoglobulin G immunology, Metallocenes, Oligopeptides chemistry, Antibodies, Monoclonal immunology, Biosensing Techniques methods, Electrochemical Techniques methods, Glycated Hemoglobin analysis
- Abstract
An electrochemical immuno-biosensor for detecting glycosylated haemoglobin (HbA1c) is reported based on glassy carbon (GC) electrodes with a mixed layer of an oligo(phenylethynylene) molecular wire (MW) and an oligo(ethylene glycol) (OEG). The mixed layer is formed from in situ-generated aryl diazonium cations. To the distal end of the MW, a redox probe 1,1'-di(aminomethyl)ferrocene (FDMA) was attached followed by the covalent attachment of an epitope N-glycosylated pentapeptide (GPP), an analogon to HbA1c, to which an anti-HbA1c monocolonal antibody IgG can selectively bind. HbA1c was detected by a competitive inhibition assay based on the competition for binding to anti-HbA1c IgG antibodies between the analyte in solution, HbA1c, and the surface bound epitope GPP. Exposure of the GPP modified sensing interface to the mixture of anti-HbA1c IgG antibody and HbA1c results in the attenuation of ferrocene electrochemistry due to free antibody binding to the interface. Higher concentrations of analyte led to higher Faradaic currents as less anti-HbA1c IgG is available to bind to the electrode surface. It was observed that there is a good linear relationship between the relative Faradaic current of FDMA and the concentration of HbA1c from 4.5% to 15.1% of total haemoglobin in serum without the need for washing or rinsing steps.
- Published
- 2012
- Full Text
- View/download PDF
13. A novel route to copper(II) detection using 'click' chemistry-induced aggregation of gold nanoparticles.
- Author
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Hua C, Zhang WH, De Almeida SR, Ciampi S, Gloria D, Liu G, Harper JB, and Gooding JJ
- Subjects
- Alkynes chemistry, Azides chemistry, Biosensing Techniques instrumentation, Catalysis, Cations, Divalent analysis, Click Chemistry instrumentation, Colorimetry methods, Cross-Linking Reagents chemistry, Cyclization, Limit of Detection, Microscopy, Electron, Scanning methods, Water Supply analysis, Water Supply standards, Biosensing Techniques methods, Click Chemistry methods, Copper analysis, Gold chemistry, Metal Nanoparticles chemistry
- Abstract
A simple colorimetric method for the detection of copper ions in water is described. This method is based on the 'click' copper(I)-catalyzed azide-alkyne cycloaddition reaction and its use in promoting the aggregation of azide-tagged gold nanoparticles by a dialkyne cross-linker is described. Nanoparticle cross-linking, evidenced as a colour change, is used for the detection of copper ions. The lowest detected concentration by the naked eye was 1.8 μM, with the response linear with log(concentration) between 1.8-200 μM. The selectivity relative to other potentially interfering ions was evaluated., (This journal is © The Royal Society of Chemistry 2012)
- Published
- 2012
- Full Text
- View/download PDF
14. An introduction to electrochemical DNA biosensors.
- Author
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Odenthal KJ and Gooding JJ
- Subjects
- Animals, Biosensing Techniques instrumentation, Electrochemistry instrumentation, Electrochemistry methods, Humans, In Situ Hybridization instrumentation, In Situ Hybridization methods, Microchemistry instrumentation, Microchemistry methods, Biosensing Techniques methods, DNA analysis
- Abstract
Electrochemical DNA biosensors exploit the affinity of single-stranded DNA for complementary strands of DNA and are used in the detection of specific sequences of DNA with a view towards developing portable analytical devices. Great progress has been made in this field but there are still numerous challenges to overcome. This review for researchers new to the field describes the components of electrochemical DNA biosensors and the important issues in their design. Methods of transducing DNA binding events are discussed along with future directions for DNA biosensors.
- Published
- 2007
- Full Text
- View/download PDF
15. Application of N-PLS calibration to the simultaneous determination of Cu(2+), Cd(2+) and Pb(2+) using peptide modified electrochemical sensors.
- Author
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Chow E, Ebrahimi D, Gooding JJ, and Hibbert DB
- Subjects
- Biosensing Techniques, Cadmium analysis, Calibration, Copper analysis, Electrochemistry instrumentation, Electrochemistry methods, Gold, Humans, Lead analysis, Least-Squares Analysis, Peptides, Metals, Heavy analysis
- Abstract
The simultaneous determination of Cu(2+), Cd(2+) and Pb(2+) is demonstrated at four modified gold electrodes using N-PLS calibration. Three of the electrodes were modified with the peptides Gly-Gly-His, gamma-Glu-Cys Gly and human angiotensin I which were covalently attached to thioctic acid self-assembled monolayers and the fourth electrode was modified with thioctic acid only. Voltammetry at the modified electrodes in the presence of the three metal ions revealed one peak due to the reduction of copper and another due to the overlapping peaks of cadmium and lead which made quantification using conventional methods difficult. N-PLS was used to calibrate and predict trace concentrations (100 nM to 10 microM) of mixtures of Cu(2+), Cd(2+) and Pb(2+).
- Published
- 2006
- Full Text
- View/download PDF
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