Patent ID: 7282373

Claim:
A self-assembled relay probe for detecting a target material, comprising: (a) a first peptide tag bound to said target material; (b) a second peptide tag bound to said target material, wherein said second peptide tag is different from said first peptide tag; (c) a first fluorescent conjugate including a first fluorochrome and a first tag binding group; wherein said first fluorescent conjugate selectively associates with said first peptide tag; and (d) a second fluorescent conjugate including a second fluorochrome having a longer wavelength and excitation and emission maxima than said first fluoroabrome and a second tag binding group, wherein said second fluorescent conjugate selectively associates with said second peptide tag, whereby upon exposure to said target material, said first and second fluorescent conjugates independently associate with said first and second peptide tags, respectively, so as to be a distance apart represented by about 0.1 R 0 to about 2 times R 0 , such that upon excitation of said first fluorescent conjugate, fluorescence resonance energy transfer results in excitation of said second fluorescent conjugate, yielding detectable emission from said second fluorescent conjugate; wherein said first fluorescent conjugate is represented by the general structural Formula (IB) wherein: (i) R 1 and R 2 , together with the arsenic atom, form a ring according to the general structural Formulae (II) wherein Z represents a hydrocarbon chain comprising 2-4 singly or doubly bonded carbon atoms wherein each carbon atom may be further substituted with one or more groups selected from hydrogen, methyl, ethyl, 1-propyl, 2-propyl, methoxy, hydroxy, amino, carboxy, sulfo, oxo, thiol, halo (fluoro, obloro, bromo, or fluoro), (CH 2 ) n″ SO 3 - and (CH 2 ) n″ SO 3 H, wherein n ″ is 1 or 2; (ii) R 4 , R 5 , R 6 and R 7 are each independently H, F, OR c ,R c , OAc, NR c , NH 2 , N(C 1 -C 4 alkyl) 2 wherein R c is H, CH(OH)CH 2 OH or (CH 2 ) q —Y, wherein q is 1-4 and Y is H, OH, NH 2 , SH, COOH, OAc, CONH 2 or CN; or R 4 with R 5 , or R 6 together with R 7 , or both, form a ring; (iii) R 8 is a linear or branched optionally substituted spacer having a minimum length of approximately 1.5Ångstroms and a maximum length of approximately 15Ångstroms; and (iv) X is a cyanine dye.