Impedance Spectroscopy and Biosensing

Pänke, Oliver; Balkenhohl, T.; Kafka, J. D.; Schäfer, Daniel; Lisdat, Fred

doi:10.1007/10_2007_081

Cited by 54 publications

(48 citation statements)

References 150 publications

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“…This might be provoked by a dampening effect of the physically adsorbed BSA blocking agent, which makes impedance measurements irreproducible as it is very sensitive, not only to analyte binding but also to the occurrence of minimal changes in the biointerface structure. 45 2. Optimization of Incubation Time.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Immunosensor for Detection of Celiac Disease Toxic Gliadin in Foodstuff

et al. 2008

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Celiac disease is a gluten-sensitive enteropathy that affects as much as 1% of the population. Patients with celiac disease should maintain a lifelong gluten-free diet, in order to avoid serious complications and consequences. It is essential to have methods of analysis to reliably control the contents of glutenfree foods, and there is a definitive need for an assay that is easy to use, and can be used on site, to facilitate the rapid testing of incoming raw materials or monitoring for gluten contamination, by industries generating gluten-free foods. Here, we report on the development of an electrochemical immunosensor exploiting an antibody raised against the putative immunodominant celiac disease epitope, for the measurement of gliadin content and potential celiac toxicity of a foodstuff. To develop the gliadin immunosensor, we explored the use of two surface chemistries, based on the use of dithiols, 22-(3,5-bis((6-mercaptohexyl)oxy)phenyl)-3,6,9,12,15,18,21-heptaoxadocosanoic acid (1) and 1,2-dithiolane-3-pentanoic acid (thioctic acid) (2), for anchoring of the capture antibody. The different surface chemistries were evaluated in terms of time required for formation of self-assembled monolayers, stability, susceptibility to nonspecific binding, reproducibility, and sensitivity. The thioctic acid self-assembled monolayer took more than 100 h to attain a stable surface and rapidly destabilized following functionalization with capture antibody, while the heptaoxadocosanoic acid surface rapidly formed (less than 3 h) and was stable for at least 5 days, stored at room temperature, following antibody immobilization. Both surface chemistries gave rise to highly sensitive immunosensors, with detection limits of 5.5 and 11.6 ng/mL being obtained for 1 and 2, respectively, with nonspecific binding of just 2.7% of the specific signal attained. The immunosensors were extremely reproducible, with RSD of 5.2 and 6.75% obtained for 1 and 2 (n ) 5, 30 ng/mL), respectively. Finally, the immunosensor was applied to the analysis of commercial gluten-free and gluten-containing raw and processed foodstuffs, and excellent correlation achieved when its performance compared to that of an ELISA.Gluten sensitivity, manifesting as celiac disease (CD), affects possibly 1:100 people in Northern Europe and North America. 1,2 Celiac disease is an inflammatory disease of the upper small intestine, results from gluten ingestion in genetically susceptible individuals, and is the only lifelong nutrient-induced enteropathy. 3,4 The small bowel abnormalities are reversed on withdrawal of gluten from the diet. CD is a familial condition with ∼10-15% of first degree relatives being similarly affected. 5 Celiac disease, when untreated or poorly treated, that is with continued ingestion of gluten, leads to a large number of complications, 6,7 which can result in considerable morbidity and repeated hospital visits. In children, symptoms such as growth retardation among others are observed 8,9 and patients with osteoporosis have a higher prevel...

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Section: Resultsmentioning

confidence: 99%

Electrochemical Immunosensor for Detection of Celiac Disease Toxic Gliadin in Foodstuff

et al. 2008

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“…Our work generated a discussion of whether it is important to use a redox probe at all [35], as also discussed by other groups [38]. Therefore, we decided to test the effect of the presence/absence of redox probe on the sensor response with a DC bias.…”

Section: Eis Sensormentioning

confidence: 91%

“…Moreover, electrochemically inert species can be conveniently measured by fEIS. Typically, measurement is performed in buffer solutions with a redox couple to probe the change in surface area of the electrodes available for the redox reaction in the presence of a DC bias across the electrodes at or above the formal potential of the redox couple [38].…”

Section: Eis Sensormentioning

confidence: 99%

An Electronic Sensor for Detection of Early-Stage Biomarker/s for Ovarian Cancer

et al. 2012

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An electronic sensor composed of interdigitated electrode arrays with nano-scale gaps has been investigated as a platform for label-free detection of ovarian cancer (OC) biomarkers. These electrodes, together with bio-affinity label-free sandwich immunoassay, were utilized as signal transducers. Electrochemical impedance spectroscopy (EIS) was employed as a technique for detection of affinity type interactions at the electrode surface. An unconventional approach is described for label-free impedimetric detection using faradic EIS at a DC bias less than the formal potential of the redox probe using nanogapped IDEAs as the transducing elements. The platform was optimized for detection of HE4, a biomarker for OC that is indicated in the early and late stages of the disease, along with CA-125 and CEA as conventional biomarkers that are currently used for diagnosis and monitoring of OC patients. The capability of the sensor platform to detect OC biomarkers in singular and multiplexed detection has been demonstrated. The sensor was successfully utilized for stand-alone detection of HE4 down to 1.5 ng/mL and was able to differentiate signal from three different biomarkers present in the same sample down to 100 pg/mL in a label-free biosensor assay.

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“…In addition, it is also a valuable tool in characterizing surface modifications, e.g., on transducer devices during the immobilization procedure of recognition elements. A thorough introduction to EIS theory, experiment, and applications could be found in a book [36] and reviews concerning EIS biosensing [37][38][39][40].…”

Section: Electrochemical Assaymentioning

confidence: 99%

Graphene for DNA Biosensing

Han

et al. 2014

SpringerBriefs in Molecular Science

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Graphene (or GO) is an excellent candidate for biomolecules anchoring and detection due to its large surface area (up to 2,630 m 2 /g) and unique sp 2 (sp 2 /sp 3 )-bonded network. According to the binding affinity difference between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) to graphene sheet, GO has been successfully adopted as a platform to discriminate DNA sequences. Fluorescent, electrochemical, electrical, surface-enhanced Raman scattering (SERS) and other methods have been utilized to achieve the sensitive, selective, and accurate DNA recognition. Both theoretical and experimental results illustrate that ssDNA sequences are adsorbed on the surface of graphene sheet with all nucleobases lying nearly flat. DNA or RNA sequencing through graphene nanopore, nanogap, and nanoribbon has also attracted much interest because it is a label-free, amplification-free, and single-molecule approach that can be scaled up for high-throughput DNA or RNA analysis. Meanwhile, miRNA detection is achieved by forming DNA-miRNA duplex helixes, and strong emission is observed due to the poor interaction between the helix and GO.Keywords DNA sequencing Á miRNA detection Á Fluorescent spectroscopy Á Electrochemical method Á Electrical method Á Graphene nanopore Á Graphene nanogap Á Graphene nanoribbon Investigation of DNA and Graphene Binding InteractionThe large surface area (up to 2,630 m 2 /g) and unique sp 2 (sp 2 /sp 3 )-bonded network make graphene (GO) an excellent candidate for biomolecules anchoring and detection. Taking DNA for the first example, various strategies have been adopted to nucleic acid sequence recognition [1][2][3][4][5][6][7][8][9][10]. To better illustrate the interaction, how nucleobases interact with graphene should be addressed, which may be inspired by the interaction of nucleobases with CNTs [11-13] and highly oriented pyrolytic graphite (HOPG) [14].

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Impedance Spectroscopy and Biosensing

Cited by 54 publications

References 150 publications

Electrochemical Immunosensor for Detection of Celiac Disease Toxic Gliadin in Foodstuff

Electrochemical Immunosensor for Detection of Celiac Disease Toxic Gliadin in Foodstuff

An Electronic Sensor for Detection of Early-Stage Biomarker/s for Ovarian Cancer

Graphene for DNA Biosensing

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