MONDAY 24th November, 1-2pm,
Dr Lynn Dennany, University of Strathclyde, UK
ELECTROCHEMICAL SENSORS FOR BIOANALYTICAL APPLICATIONS
Electrochemical based detection methods are of growing importance in several areas of analytical chemistry especially in medical-diagnostics-related applications. However, a key issue is that the sensitivity of these assays is often not sufficient to allow disease biomarkers to be detected at a sufficiently low concentration so as to change clinical practice, e.g., to use cardiac Troponin I (TNI) to diagnose myocardial infarction within the emergency room demand a rapid test with a picomolar limit of detection. Electrochemiluminescence (ECL) can offer a solution and can play an increasing role in the development of biomedical point-of-care devices.
Fig. 1: Schematic of ECL production from Nafion/QD films.
Since pioneering works from Bard’s group that reported for the first time the electrochemiluminescence (ECL) properties of CdSe1, and CdTe nanocrystals2, analytical applications of the ECL from QDs have increased dramatically over the last years. This is primarily due to the significant advantages of the ECL over conventional spectroscopic techniques, in particular, low background signals and the ability to control both time and position of the light emitting reactions accurately.
Positively charged dimethylaminoethanethiol (DAET)-protected core-shell CdSe/ZnS quantum dots (QDs) were incorporated within negatively charged Nafion films. The ECL behaviour of such films was characterized using hydrogen peroxide and peroxidisulfate as the co-reactants. The results showed an enhancement of the ECL signal for the Nafion/QDs composite film in comparison with the bare QDs deposited on the electrode surface when hydrogen peroxide was used as a co-reactant. Interestingly, Nafion/QDs composite films were completely insensitive when peroxidisulphate was used as the coreactant, as an indication of the permselectivity of Nafion towards negatively charged species. To show the suitability of Nafion/QDs composite films for ECL detection, we have investigated the ECL quenching of Nafion/QDs composite film at different concentrations of glutathione. The results showed a linear relation of the quenching of the ECL signal with the increase of the concentration of glutathione using hydrogen peroxide as the coreactant. These results pointed out the suitability of Nafion/QDs composite films for electroanalytical applications.
Fig. 2: ECL response films, on the [H2O2] at a scan rate of 100 mV s-1. Inset shows the linear dependence of ECL intensity as a function of [H2O2]. Adapted from reference 3.
- Myung, N., Ding, Z.F., Bard, A.J., 2002. Nano Lett. 2, 1315-1319. Myung, N., Bae, Y., Bard, A.J., 2003. Nano Lett. 3, 1053-1055.
- Bae, Y., Myung, N., Bard, A.J., 2004. Nano Lett. 4, 1153-1161.
- Dennany, L. M.Gerlach, S. O’Carroll, T.E. Keyes, R.J. Forster, P.Bertoncello, J. Mater.Chem, 2011, 21, 13984-13990.
LD would like to acknowledge financial funding from the European Union 7th Framework Programme (FP7/2007-2013) from a Marie Curie Reintegration Grant (PIRG07-GA-2010-268236) and the RSC Analytical Biosciences Group Bursary.
Dr. Lynn Dennany got her PhD entitled “Electrochemiluminescent (ECL) & Amperometric Detection of DNA & DNA Damage” in 2004 from Dublin City University. Following on from this she worked at the Biomedical Diagnostics Institute examining the electrochemical applications of ruthenium based metallopolymers for biomedical diagnostics. She then went to work at the Intelligent Polymer Research Institute at the University of Wollongong, where she worked on the targeted modification of conducting polymers for sensor and solar cell applications. She is currently working at the University of Strathclyde. Her main interests focus on the application of analytical detection techniques for chemical and biochemical sensor development. I am particularly interested in the creation of novel materials that have tuneable electronic or photonic properties. These materials can be utilised for new applications in a variety of areas ranging from biomedical devices to forensic applications.
New theoretical insights into factors which influence electron transfer are also investigated. This fundamental work can impact directly on our understanding of a wide variety of fields and influence future sensor development.
Department of Pure & Applied Chemistry, University of Strathclyde, Royal College, 204 George Street, Glasgow, G1 1XW, Scotland, UK. Fax: +141 548 2532; Tel: +141 548 4322; E-mail: email@example.com
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