Card-based biosensor device
First Claim
1. A diagnostic card device for use in detecting or quantitating an analyte present in a liquid sample, comprising,a card substrate having formed therein a sample introduction region, a biosensor, and a sample-flow pathway communicating between said sample-introduction region and said biosensor, circuitry for generating an analyte-dependent electrical signal from the biosensor;
- and, a signal-responsive element for recording said signal, wherein said biosensor has a detection surface with surface-bound molecules of a first charged, coil-forming peptide for interacting with a second, oppositely charged coil-forming peptide to form a stable α
-helical coiled-coil heterodimer, where the binding of the second peptide to the first peptide, to form said heterodimer, is effective to measurably alter a signal generated by the biosensor, and said sample-flow pathway contains (i) a conjugate of (ia) the second coil-forming peptide and (ib) the analyte or an analyte analog, and (ii) an analyte-binding agent immobilized within the pathway, wherein sample introduced in said sample introduction region is carried through the sample-flow pathway, where the analyte competes with said conjugate for binding to said analyte-binding agent, such that the presence of increasing amounts of analyte leads to increasing amounts of unbound conjugate which is then free to react with said first peptide in said biosensor to alter the signal generated by the biosensor in proportion to the amount of analyte present.
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Accused Products
Abstract
A diagnostic card device for use in detecting or quantitating an analyte present in a liquid sample, comprising a card substrate having a sample introduction region, a biosensor, and a sample-flow pathway communicating between the sample-introduction region and the biosensor, circuitry for generating an analyte-dependent electrical signal from the biosensor; and a signal-responsive element for recording such signal. In one embodiment, the biosensor includes a detection surface with surface-bound molecules of a first charged, coil-forming peptide capable of interacting with a second, oppositely charged coil-forming peptide to form a stable α-helical coiled-coil heterodimer, where the binding of the second peptide to the first peptide, to form such heterodimer, is effective to measurably alter a signal generated by the biosensor. The sample-flow pathway contains diffusibly bound conjugate of the second coil-forming peptide and the analyte (or an analyte analog) and immobilized analyte-binding agent. The analyte in the liquid sample and the conjugate compete for binding with the immobilized analyte-binding agent. Unbound conjugate migrates by capillarity to the biosensor. Liquid sample containing conjugate migrates in the sample flow pathway by capillary action or is driven by a micro-pump. In another embodiment, the biosensor includes an electrode substrate coated with a high-dielectric hydrocarbon-chain monolayer, and having analyte-binding agent attached to the exposed monolayer surface. Binding of analyte to the monolayer-bound analyte-binding agent, and the resultant perturbation of the monolayer structure, causes ion-mediated electron flow across the monolayer.
272 Citations
16 Claims
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1. A diagnostic card device for use in detecting or quantitating an analyte present in a liquid sample, comprising,
a card substrate having formed therein a sample introduction region, a biosensor, and a sample-flow pathway communicating between said sample-introduction region and said biosensor, circuitry for generating an analyte-dependent electrical signal from the biosensor; - and,
a signal-responsive element for recording said signal, wherein said biosensor has a detection surface with surface-bound molecules of a first charged, coil-forming peptide for interacting with a second, oppositely charged coil-forming peptide to form a stable α
-helical coiled-coil heterodimer, where the binding of the second peptide to the first peptide, to form said heterodimer, is effective to measurably alter a signal generated by the biosensor, and said sample-flow pathway contains (i) a conjugate of (ia) the second coil-forming peptide and (ib) the analyte or an analyte analog, and (ii) an analyte-binding agent immobilized within the pathway, wherein sample introduced in said sample introduction region is carried through the sample-flow pathway, where the analyte competes with said conjugate for binding to said analyte-binding agent, such that the presence of increasing amounts of analyte leads to increasing amounts of unbound conjugate which is then free to react with said first peptide in said biosensor to alter the signal generated by the biosensor in proportion to the amount of analyte present.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- and,
Specification