Label-Free Optical Sensing and Characterization of Biomolecules by D8 or D10 Metal Complexes

A composition for characterizing a multiply-charged biomolecule comprising a charged d8 or d10 metal complex, wherein the metal complex electrostatically binds to the multiple-charged biomolecule to induce aggregation and helical self-assembly of the metal complex through metal . . . metal interactions, π . . . π interactions, or a combination of both types of interactions.

An assay method for detecting the presence of a target multiple-charged biomolecule in a sample comprising:

• (a) combining a charged d8 or d10 metal complex, wherein the metal complex comprising at least one transition metal and at least one corresponding coordinating ligand, with the sample potentially containing the target multiple-charged biomolecule under conditions effective to allow the d8 or d10 metal complex and the target multiple-charged biomolecule to bind to each other by electrostatic interactions, and to allow subsequent self-assembly of a charged d8 or d10 metal complex aggregate, and
• (b) measuring optical properties of the charged d8 or d10 metal complex aggregate.

A kit for use in detecting a multiple-charged biomolecule in a sample comprising:

• (a) a composition comprising a charged d8 or d10 metal complex, wherein the metal complex electrostatically binds to the multiple-charged biomolecule to induce aggregation and self-assembly of the d8 or d10 metal complex through metal . . . metal interactions and π . . . π interactions, and
• (b) instructions for use.