title: Simple, sensitive, and quantitative electrochemical detection method for paper analytical devices.
abstract: We report a new type of paper analytical device that provides quantitative electrochemical output and detects concentrations as low as 767 fM. The model analyte is labeled with silver nanoparticles (AgNPs), which provide 250,000-fold amplification. AgNPs eliminate the need for enzymatic amplification, thereby improving device stability and response time. The use of magnetic beads to preconcentrate the AgNPs at the detection electrode further improves sensitivity. Response time is improved by incorporation of a hollow channel, which increases the flow rate in the device by a factor of 7 and facilitates the use of magnetic beads. A key reaction necessary for label detection is made possible by the presence of a slip layer, a fluidic switch that can be actuated by manually slipping a piece of paper. The design of the device is versatile and should be useful for detection of proteins, nucleic acids, and microbes.
authors.affiliation: Department of Chemistry and Biochemistry and the Center for Nano- and Molecular Science and Technology, The University of Texas at Austin , 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States.
authors.forename: Karen
authors.initials: K
authors.lastname: Scida
authors.forename: Josephine C
authors.initials: JC
authors.lastname: Cunningham
authors.forename: Christophe
authors.initials: C
authors.lastname: Renault
authors.forename: Ian
authors.initials: I
authors.lastname: Richards
authors.forename: Richard M
authors.initials: RM
authors.lastname: Crooks
mesh_terms: D055664:Electrochemical Techniques / Q000191:economics / Q000295:instrumentation*; D004867:Equipment Design; D059346:Magnets / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010209:Paper; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver