Nucleic acid enzyme biosensors for ions
View Patent ↗Disclosed are compositions and methods for the sensitive and selective detection of ions using nucleic acid enzymes.
1. A method of detecting the presence of an ion comprising:
(a) contacting a nucleic acid enzyme, the enzyme dependent on the ion to produce a product from a substrate, with a sample suspected of containing an ion; and
(b) measuring the product of the nucleic acid enzymatic reaction;
wherein the ion is a metal ion that is not Mg 2+ , and
the substrate comprises a fluorophore and the enzyme comprises a quencher of the fluorophore, or the enzyme comprises a fluorophore and the substrate comprises a quencher of the fluorophore.
2. The method of claim 1 , wherein the nucleic acid enzyme comprises a ribozyme.
3. The method of claim 1 , wherein the nucleic acid enzyme comprises a deoxyribozyme.
4. The method of claim 1 , wherein the nucleic acid enzyme and the substrate comprise separate nucleic acid strands.
5. The method of claim 4 , wherein the substrate comprises a fluorophore and the enzyme comprises a quencher of the fluorophore.
6. The method of claim 5 , wherein a 5′-end of the substrate comprises the fluorophore.
7. The method of claim 6 , wherein a 3′-end of the enzyme comprises the quencher for the fluorophore.
8. The method of claim 5 , wherein the fluorophore is TAMRA.
9. The method of claim 8 , wherein the quencher is DABCYL.
10. The method of claim 1 , wherein the ion is an anion, a monovalent cation, a divalent cation that is not Mg 2+ , a trivalent cation, or a polyvalent ion that is not Mg 2+ is Ce 4+ .
11. The method of claim 10 , wherein the ion is an anion.
12. The method of claim 10 , wherein the ion is a monovalent cation.
13. The method of claim 12 , wherein the monovalent cation is selected from the group consisting of K + , Na + , Li + , Tl + , and Ag + .
14. The method of claim 10 , wherein the ion is a divalent cation that is not Mg 2+ .
15. The method of claim 14 , wherein the divalent cation that is not Mg 2+ is selected from the group consisting of Ca 2+ , Mn 2+ , Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Cu 2+ , Pb 2+ , Hg 2+ , Pt 2+ , Ra 2+ , Ba 2+ , and Sr 2+ .
16. The method of claim 1 , wherein the metal ion is Pb 2+ .
17. The method of claim 10 , wherein the ion is a trivalent cation.
18. A biosensor comprising:
(a) a nucleic acid enzyme dependent on an ion to produce a product from a substrate; and
(b) the substrate;
wherein the ion is not Mg 2+ , and
the substrate comprises a fluorophore and the enzyme comprises a quencher of the fluorophore, or the enzyme comprises a fluorophore and the substrate comprises a quencher of the fluorophore.
19. A composition comprising a nucleic acid enzyme linked to a fluorophore,
wherein the nucleic acid enzyme is responsive to an ion selected from the group consisting of K + , Na + , Li + , Tl + , Ag + , Ca 2+ , Mn 2+ , Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Cu 2+ , Pb 2+ , Hg 2+ , Pt 2+ , Ra 2+ , Ba 2+ , Sr 2+ , Co 3+ , Cr 3+ , Ln 3+ , and Ce 4+ .
20. The method of claim 17 , wherein the trivalent cation is Co 3+ , Cr 3+ , or Ln 3+ .
21. The biosensor of claim 18 , wherein the ion is selected from the group consisting of K + , Na + , Li + , Tl + , Ag + , Ca 2+ , Mn 2+ , Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Cu 2+ , Pb 2+ , Hg 2+ , Pt 2+ , Ra 2+ , Ba 2+ , Sr 2+ , Co 3+ , Cr 3+ , Ln 3+ , and Ce 4+ .
22. The method of claim 10 , wherein the polyvalent ion that is not Mg 2+ is Ce 4+ .