Impedance spectroscopy and biosensing
ABSTRACT This chapter introduces the basic terms of impedance and the technique of impedance measurements. Furthermore, an overview of the application of this transduction method for analytical purposes will be given. Examples for combination with enzymes, antibodies, DNA but also for the analysis of living cells will be described. Special attention is devoted to the different electrode design and amplification schemes developed for sensitivity enhancement. Finally, the last two sections will show examples from the label-free determination of DNA and the sensorial detection of autoantibodies involved in celiac disease.
SourceAvailable from: Attila Bonyár5th European Conference of the International Federation for Medical and Biological Engineering, Edited by Ákos Jobbágy, 01/2012: chapter 281: pages 1082-1085; Springer Berlin Heidelberg., ISBN: 9783642235078
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ABSTRACT: Nano-MnO2/chitosan composite film modified glassy carbon electrode (MnO2/CHIT/GCE) was fabricated and a DNA probe was immobilized on the electrode surface. The immobilization and hybridization events of DNA were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The EIS was applied to the label-free detection of the target DNA. The human immunodeficiency virus (HIV) gene fragment was successfully detected by this DNA electrochemical sensor. The dynamic detection range was from 2.0 × 10-11 to 2.0 × 10-6 mol/L, with a detection limit of 1.0 × 10-12 mol/L.Analytical Letters 11/2009; 42(18). DOI:10.1080/00032710903276638 · 0.98 Impact Factor
Article: Point-of-Care Platforms.[Show abstract] [Hide abstract]
ABSTRACT: Point-of-care applications are gaining increasing interest in clinical diagnostics and emergency applications. Biosensors are used to monitor the biomolecular interaction process between a disease biomarker and a recognition element such as a reagent. Essential are the quality and selectivity of the recognition elements and assay types used to improve sensitivity and to avoid nonspecific interactions. In addition, quality measures are influenced by the detection principle and the evaluation strategies. For these reasons, this review provides a survey and validation of recognition elements, assays, and various types of detection methods for point-of-care testing (POCT) platforms. Common applications of clinical parameters are discussed and considered. In this ever-changing field, a snapshot of current applications is needed. We provide such a snapshot by way of a table including literature citations and also discuss these applications in more detail throughout.Annual Review of Analytical Chemistry (2008) 06/2014; 7(1):297-315. DOI:10.1146/annurev-anchem-071213-020332 · 7.81 Impact Factor