Abstract: The invention provides compositions, kits, methods, and species that include electroactive entities which can serve as signaling entities in chemical and/or biochemical assays. The electroactive species can be metallocenes, such as ferrocenes, including substituents that affect the oxidation/reduction potential (redox potential) of the species. By controlling the redox potential of the species, multiple species can be used in a single assay, each species having a different redox potential, for simultaneous signaling of different binding events. Additionally, species having redox potentials lower than 490 mV can be provided, allowing signaling within a potential range easily detectable in the presence of biological fluids.

Abstract: Customized therapeutics and in situ diagnostics for patient therapy and diagnosis takes advantage of tools including techniques for derivatizing colloids with self-assembled monolayers. This provides the capability of a wide variety of assays including chemical or biochemical agent/agent interaction studies. Bio-derivatized colloids, with or without signaling entities, are used to probe interactions with species on non-colloidal structures. The invention provides techniques for immobilizing colloidal particles on a wide variety of non-colloidal structures. Included is the ability to decorate a variety of non-colloidal structures including beads, with colloids as a detectable assay. This allows, in many cases, assays detectable via the unaided human eye, as well as assays detectable via automated determination of a change of interaction of electromagnetic radiation with the colloids, e.g., absorption, light-scattering, and the like.

Abstract: Chemical, biological, and/or biochemical assays of the invention utilize intermediate binding entities for binding interactions. For example, a colloid particle carrying a species that could harm a component in the assay is allowed to binding interact in the assay only after other, more sensitive components have finished their binding interactions. In another example, multi-step binding interactions are used where single-step interactions could be used, so as to reduce false positives.

Abstract: The invention provides novel techniques for determining the interaction between binding partners. The first binding partner is immobilized to a surface or a colloid and a second binding partner immobilized to a surface or a colloid. Non-specific binding techniques, including a SAM, provide for the immobilization of a wide variety of species. A mixture may be separated into various components and these components may then be fastened to either the colloids or the surfaces. Binding interaction between the binding partners may be determined through a variety of assays.