Patent ID: 7582260

Claim:
An optical labeling molecule for labeling a target analyte comprising: a. a boron difluoride diaza-indacene-propionic acid (BODIPY) zwitterionic dye moiety comprising at least one positive or at least one negative charge moiety added to obtain a net neutral charge, wherein the positive charge moiety is selected from a group consisting of a quaternary ammonium group and a guanidinium group, wherein the positive charge moiety is not titratable between the pH of 3-12, and wherein the negative charge moiety is selected from the group consisting of a sulfonate group and a sulfate group, wherein the negative charge moiety is not titratable between the pH of 3-12; b. a functional linker moiety; and c. a titratable group moiety, wherein the titratable group is a tertiary amine which closely approximates the pK of the group removed from the target analyte by reaction with the functional linker.