title: Electrochemical microfluidic biosensor for nucleic acid detection with integrated minipotentiostat.
abstract: An electrochemical microfluidic biosensor with an integrated minipotentiostat for the quantification of RNA was developed based on nucleic acid hybridization and liposome signal amplification. Specificity of the biosensor was ensured by short DNA probes that hybridize with the target RNA or DNA sequence. The reporter probe was coupled to liposomes entrapping the electrochemically active redox couple potassium ferri/ferrohexacyanide. The capture probes were coupled to superparamagnetic beads that were isolated on a magnet in the biosensor. Upon capture, the liposomes were lysed to release the electrochemical markers that were detected on an interdigitated ultramicroelectrode array in the biosensor just downstream of the magnet. The current was measured, stored and displayed by miniaturized instrumentation (miniEC). The accuracy of the miniEC was evaluated by comparing its performance to a standard bench-top electrochemical workstation in static and dynamic DC amperometric experiments. In both sets of experiments, the inexpensive miniEC performance was comparable in signal strength to that of the electrochemical workstation. In fact, the miniEC achieved a detection limit of 0.01 microM combined ferri/ferrohexacyanide concentration which was 10 x lower than that of the standard lab-bench system. The response time of the miniEC system was the same for low concentrations taking about 10 s to steady state. It was, however, slower at higher concentrations, taking 5 s versus only 1 s for the bench-top system. Finally, the functionality of the miniEC was successfully demonstrated with the detection of Dengue virus RNA.
authors.affiliation: Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Kwakye
authors.forename: Vasily N
authors.initials: VN
authors.lastname: Goral
authors.forename: Antje J
authors.initials: AJ
authors.lastname: Baeumner
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004247:DNA / Q000032:analysis*; D004209:Disposable Equipment; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008081:Liposomes / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D008904:Miniaturization; D009696:Nucleic Acids / Q000032:analysis; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012367:RNA, Viral / Q000032:analysis*; D017423:Sequence Analysis, RNA / Q000379:methods*; D018511:Systems Integration
chemical_list: D008081:Liposomes; D009696:Nucleic Acids; D012367:RNA, Viral; D004247:DNA