Label-free optical sensing and characterization of biomolecules by d

1. A composition for detecting or characterizing nucleic acid enzymatic cleavage comprising a charged d 8 or d 10 metal complex, wherein the charged d 8 or d 10 metal complex electrostatically binds to a multiple-charged biomolecule to induce aggregation and self-assembly of the metal complex through metal-metal interactions, π . . . π interactions, or a combination of both interactions and wherein the metal complex comprises at least one transition metal, at least one carbon donor ligand, and at least one corresponding coordinating ligand; and wherein the carbon donor ligand has one of the following structures:

2. A composition for detecting or characterizing nucleic acid radical damage comprising a charged d 8 or d 10 metal complex, wherein the charged d 8 or d 10 metal complex electrostatically binds to a multiple-charged biomolecule to induce aggregation and self-assembly of the metal complex through metal-metal interactions, π . . . π interactions, or a combination of both interactions, and wherein the metal complex comprises at one least transition metal, at least one carbon donor legend, and at least one corresponding coordinating ligand; and wherein the carbon donor ligand has one of the following structures:

3. A composition for detecting or characterizing nucleic acid G-quadruplex formation and label-free selective sensing of potassium ion comprising a charged d 8 or d 10 metal complex, wherein the charged d 8 or d 10 metal complex electrostatically binds to a multiple-charged biomolecule to induce aggregation and self-assembly of the metal complex through metal-metal interactions, π . . . π interactions, or a combination of both interactions, and wherein the metal complex comprises at one least transition metal, at least one carbon donor ligand, and at least one corresponding coordinating ligand; and wherein the carbon donor ligand has one of the following structures:

4. The composition of claim 1 , wherein the self-assembly creates optical property changes to the metal complex.

5. The composition of claim 2 , wherein the self-assembly creates optical property changes to the metal complex.

6. The composition of claim 3 , wherein the self-assembly creates optical property changes to the metal complex.

7. The composition of claim 1 , wherein the optical property change is UV/vis, emission, or CD intensity change.

8. The composition of claim 2 , wherein the optical property change is UV/vis, emission, or CD intensity change.

9. The composition of claim 3 , wherein the optical property change is UV/vis, emission, or CD intensity change.

10. The composition of claim 1 , wherein the at least one transition metal is platinum (Pt), gold (Au), palladium (Pd), rhodium (Rh), iridium (Ir), or silver (Ag).

11. The composition of claim 2 , wherein the at least one transition metal is platinum (Pt), gold (Au), palladium (Pd), rhodium (Rh), iridium (Ir), or silver (Ag).

12. The composition of claim 3 , wherein the at least one transition metal is platinum (Pt), gold (Au), palladium (Pd), rhodium (Rh), iridium (Ir), or silver (Ag).

13. The composition of claim 1 , wherein one or more of the corresponding coordinating ligands is a nitrogen donor ligand.

14. The composition of claim 2 , wherein one or more corresponding coordinating ligands is a nitrogen donor ligand.

15. The composition of claim 3 , wherein one or more corresponding coordinating ligands is a nitrogen donor ligand.

16. The composition of claim 13 , wherein the nitrogen donor ligand is pyridine, bipyridine, terpyridine, polypyridine, arylpyridine, diarylpyridine, arylbipyridine, phenanthroline, diazine, triazine, phthalocyanine, imine, diimine, triimine, or porphyrin.

17. The composition of claim 14 , wherein the nitrogen donor ligand is pyridine, bipyridine, terpyridine, polypyridine, arylpyridine, diarylpyridine, arylbipyridine, phenanthroline, diazine, triazine, phthalocyanine, imine, diimine, triimine, or porphyrin.

18. The composition of claim 15 , wherein the nitrogen donor ligand is pyridine, bipyridine, terpyridine, polypyridine, arylpyridine, diarylpyridine, arylbipyridine, phenanthroline, diazine, triazine, phthalocyanine, imine, diimine, triimine, or porphyrin.

19. The composition of claim 1 , wherein the metal complex has a planar structure or a partially planar structure, and at least one corresponding coordinating ligand is capable of π . . . π stacking interactions.

20. The composition of claim 2 , wherein the metal complex has a planar structure or a partially planar structure, and at least one corresponding coordinating ligand is capable of π . . . π stacking interactions.

21. The composition of claim 3 , wherein the metal complex has a planar structure or a partially planar structure, and at least one corresponding coordinating ligand is capable of π . . . π stacking interactions.

22. The composition of claim 1 , wherein the at least one transition metal is platinum (Pt).

23. The composition of claim 2 , wherein the at least one transition metal is platinum (Pt).

24. The composition of claim 3 , wherein the at least one transition metal is platinum (Pt).

25. The composition of claim 1 , wherein the at least one corresponding coordinating ligand is terpyridine.

26. The composition of claim 2 , wherein the at least one corresponding coordinating ligand is terpyridine.

27. The composition of claim 3 , wherein the at least one corresponding coordinating ligand is terpyridine.

28. The composition of claim 1 , wherein the at least one transition metal is platinum (Pt) and at least one corresponding coordinating ligand is terpyridine.

29. The composition of claim 2 , wherein the at least one transition metal is platinum (Pt) and at least one corresponding coordinating ligand is terpyridine.

30. The composition of claim 3 , wherein the at least one transition metal is platinum (Pt) and at least one corresponding coordinating ligand is terpyridine.

31. The composition of claim 1 , wherein the at least one carbon donor ligand has the following structure:

32. The composition of claim 2 , wherein the at least one carbon donor ligand has the following structure:

33. The composition of claim 3 , wherein the at least one carbon donor ligand has the following structure:

34. The composition of claim 1 , wherein the at least one carbon donor ligand has the following structure:

35. The composition of claim 2 , wherein the at least one carbon donor ligand has the following structure:

36. The composition of claim 3 , wherein the at least one carbon donor ligand has the following structure:

37. The composition of claim 1 , wherein the at least one carbon donor ligand has the following structure:

38. The composition of claim 2 , wherein the at least one carbon donor ligand has the following structure:

39. The composition of claim 3 , wherein the at least one carbon donor ligand has the following structure:

40. The composition of claim 1 , wherein the at least one carbon donor ligand has the following structure:

41. The composition of claim 2 , wherein the at least one carbon donor ligand has the following structure:

42. The composition of claim 3 , wherein the at least one carbon donor ligand has the following structure:

43. An assay method for detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a) combining a charged d 8 or d 10 metal complex as set forth in claim 1 , wherein the metal complex contains at least one transition metal and at least one corresponding coordinating ligand, with the sample potentially containing the target nucleic acid under conditions effective to allow the d 8 or d 10 metal complex and the nucleic acid to bind to each other by electrostatic interactions, and to allow subsequent self-assembly of a charged d 8 or d 10 metal complex aggregate, and

b) measuring optical properties of the charged d 8 or d 10 metal complex aggregate.

44. A kit for use in detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a composition that contains a charged d 8 or d 10 metal complex as set forth in claim 1 , wherein the metal complex electrostatically binds to the nucleic acid to induce aggregation and self-assembly of the d 8 or d 10 metal complex through metal-metal interactions and/or π . . . π interactions, and

b) instructions for use.

45. An assay method for detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a) combining a charged d 8 or d 10 metal complex as set forth in claim 2 , wherein the metal complex contains at least one transition metal and at least one corresponding coordinating ligand, with the sample potentially containing the target nucleic acid under conditions effective to allow the d 8 or d 10 metal complex and the nucleic acid to bind to each other by electrostatic interactions, and to allow subsequent self-assembly of a charged d 8 or d 10 metal complex aggregate, and

b) measuring optical properties of the charged d 8 or d 10 metal complex aggregate.

46. A kit for use in detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a) a composition that contains a charged d 8 or d 10 metal complex as set forth in claim 2 , wherein the metal complex electrostatically binds to the nucleic acid to induce aggregation and self-assembly of the d 8 or d 10 metal complex through metal-metal interactions and/or π . . . π interactions, and

b) instructions for use.

47. An assay method for detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a) combining a charged d 8 or d 10 metal complex as set forth in claim 3 , wherein the metal complex contains at least one transition metal and at least one corresponding coordinating ligand, with the sample potentially containing the target nucleic acid under conditions effective to allow the d 8 or d 10 metal complex and the nucleic acid to bind to each other by electrostatic interactions, and to allow subsequent self-assembly of a charged d 8 or d 10 metal complex aggregate, and

b) measuring optical properties of the charged d 8 or d 10 metal complex aggregate.

48. A kit for use in detecting nucleic acid enzymatic cleavage, radical damage, or G-quadruplex formation and potassium sensing in a sample comprising:

a) a composition that contains a charged d 8 or d 10 metal complex as set forth in claim 3 , wherein the metal complex electrostatically binds to the nucleic acid to induce aggregation and self-assembly of the d 8 or d 10 metal complex through metal-metal interactions and/or π . . . π interactions, and

b) instructions for use.