Bunyakul, Natinan and Promptmas, Chamras and Baeumner, Antje J. (2015) Microfluidic biosensor for cholera toxin detection in fecal samples. ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 407 (3). pp. 727-736. ISSN 1618-2642, 1618-2650
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Sample preparation and processing steps are the most critical assay aspects that require our attention in the development of diagnostic devices for analytes present in complex matrices. In the best scenarios, diagnostic devices should use only simple sample processing. We have therefore investigated minimal preparation of stool samples and their effect on our sensitive microfluidic immunosensor for the detection of cholera toxin. This biosensor was previously developed and tested in buffer solutions only, using either fluorescence or electrochemical detection strategies. The microfluidic devices were made from polydimethylsiloxane using soft lithography and silicon templates. Cholera toxin subunit B (CTB)-specific antibodies immobilized onto superparamagnetic beads and ganglioside GM(1)-containing liposomes were used for CTB recognition in the detection system. Quantification of CTB was tested by spiking it in human stool samples. Here, optimal minimal sample processing steps, including filtration and centrifugation, were optimized using a microtiter plate assay owing to its high-throughput capabilities. Subsequently, it was transferred to the microfluidic systems, enhancing the diagnostic characteristic of the biosensor. It was found that the debris removal obtained through simple centrifugation resulted in an acceptable removal of matrix effects for the fluorescence format, reaching a limit of detection of only 9.0 ng/mL. However, the electron transfer in the electrochemical format was slightly negatively affected (limit of detection of 31.7 ng/mL). Subsequently, cross-reactivity using the heat-labile Escherichia coli toxin was investigated using the electrochemical microfluidic immunosensors and was determined to be negligible. With minimal sample preparation required, these microfluidic liposome-based systems have demonstrated excellent analytical performance in a complex matrix and will thus be applicable to other sample matrices.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ULTRASENSITIVE DETECTION; SENSITIVE DETECTION; IMMUNOASSAY; IMMUNOSENSOR; GANGLIOSIDE; BIOMARKER; DIARRHEA; Biosensor; Microfluidic; Liposomes; Cholera toxin; Fecal sample |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik > Chemo- und Biosensorik (Prof. Antje J. Bäumner, formerly Prof. Wolfbeis) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 02 Aug 2019 09:34 |
| Last Modified: | 02 Aug 2019 09:34 |
| URI: | https://pred.uni-regensburg.de/id/eprint/6318 |
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