Electrochemiluminescence of rare earth metal chelates

Abstract

Luminescent chemical reagents that include complexes of rare earth metals with ligands such as aromatic heterocyclic nitrogen-containing compounds and semi-aromatic oxygen-containing compounds are used to detect small quantities of complex substances such as pharmaceuticals, metabolites, and microorganisms in complex sample mixtures.

1 . A method of determining the presence of a chemical moiety, said chemical moiety having the formula
   [MPL 1 L 2 -(-link-)-] t B   wherein M is a lanthanide;   P is a polydentate ligand of M;   L 1  and L 2  are ligands of M, each of which may be a substance covalently bound to one or more of P, L 1  or L 2  through one or more covalent bond linkages, said linkages designated as (-link-) and being covalent bonds linking B with at least one of P, L 1  or L 2 ;   t is an integer equal to or greater than 1;   B is a biological substance or a synthetic substance which is capable of competing with the biological substance;   P, L 1  or L 2 , and B are of such number that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1  or L 2 , and B are of such composition that the chemical moiety can be induced to repeatedly emit electromagnetic radiation; and wherein the method comprises:   (a) forming a reagent mixture containing the chemical moiety;   (b) exposing the reagent mixture to electrochemical energy, the potential of which oscillates between a potential sufficiently positive and sufficiently negative to induce the chemical moiety to oscillate between at least two oxidization states, thereby inducing the chemical moiety to repeatedly electrochemiluminesce; and   (c) detecting emitted luminescence thereby to determine the presence of the chemical moiety.   
   
   
       2 . A method of determining the presence of a chemical moiety, said chemical moiety having the formula
   [MPL 1 L 2 -(-link-)-] t B   wherein M is a lanthanide;   P is a polydentate ligand of M;   L 1  and L 2  are ligands of M, each of which may be a substance covalently bound to one or more of P, L 1  or L 2  through one or more covalent bond linkages, said linkages designated as (-link-) and being covalent bonds linking B with at least one of P L 1  or L 2 ;   t is an integer equal to or greater than 1;   B is a biological substance or a synthetic substance which is capable of competing with the biological substance;   P, L 1  or L 2 , and B are of such number that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1  or L 1 , and B are of such composition that the chemical moiety can be induced to repeatedly emit electromagnetic radiation;   and wherein the method comprises:   (a) forming a reagent mixture containing the chemical moiety and an agent which upon exposure of the reagent mixture to electrochemical energy forms a reductant;   (b) exposing the reagent mixture to electrochemical energy such that the agent forms a reductant, thereby inducing the chemical moiety to repeatedly electrochemiluminesce; and   (c) detecting emitted luminescence thereby to determine the presence of the chemical moiety.   
   
   
       3 . A competitive binding method of determining the presence of an analyte of interest wherein the analyte and a chemical moiety bind competitively to a complementary material, which comprises
 (a) forming a reagent mixture comprising a sample that may contain the analyte of interest, the complementary material, and the chemical moiety such that the chemical moiety and the analyte of interest bind competitively to the complementary material; said chemical moiety having the formula
   [MPL 1 L 2 -(-link-)-] t B 
   wherein M is a lanthanide;   P is a polydentate ligand of M;   L 1  and L 2  are ligands of M, each of which may be a substance covalently bound to one or more of P, L 1  or L 2  through one or more covalent bond linkages, said linkages designated as (-link-) and being covalent bonds linking B with at least one of P, L 1  or L 2 ;   t is an integer equal to or greater than 1;   B is a biological substance or a synthetic substance which is capable of competing with the analyte;   P, L 1 , L 2 , and B are of such number that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1 , L 2 , and B are of such composition that the chemical moiety can be induced to repeatedly emit electromagnetic radiation;   (b) exposing the reagent mixture to electrochemical energy, the potential of which oscillates between a potential sufficiently positive and sufficiently negative to induce the chemical moiety to oscillate between at least two oxidization states, thereby inducing the chemical moiety to repeatedly electrochemiluminesce; and   (c) detecting emitted luminescence thereby to determine the presence of the analyte of interest.   
   
   
       4 . A competitive binding method of determining the presence of an analyte of interest wherein the analyte and a chemical moiety bind competitively to a complementary material, which comprises
 (a) forming a reagent mixture comprising a sample that may contain the analyte of interest, the complementary material, the chemical moiety, and an agent which upon exposure of the reagent mixture to electrochemical energy forms a reductant, such that the chemical moiety and the analyte of interest bind competitively to the complementary material; said chemical moiety having the formula
   [MPL 1 L 2 -(-link-)-] t B 
   wherein M is a lanthanide;   P is a polydentate ligand of M;   L 1  and L 1  are ligands of M, each of which may be a substance covalently bound to one or more of P, L 1  or L 2  through one or more covalent bond linkages, said linkages designated as (-link-) and being covalent bonds linking B with at least one of P, L 1  or L 2 ;   t is an integer equal to or greater than 1;   B is a biological substance or a synthetic substance which is capable of competing with the analyte;   P, L 1 , L 2 , and B are of such number that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1 , L 2 , and B are of such composition that the chemical moiety can be induced to repeatedly emit electromagnetic radiation;   (b) exposing the reagent mixture to electrochemical energy such that the agent forms a reductant, thereby inducing the chemical moiety to repeatedly electrochemiluminesce; and   (c) detecting emitted luminescence thereby to determine the presence of the analyte of interest.   
   
   
       5 . A chemical moiety having the formula:
   [MPL 1 L 2 -(-link-)-] t B   wherein M is a lanthanide element;   L 1  and L 2  are ligands of M;   P is a bypyridyl or diketone-type polydentate ligand of M, wherein P has at least one linking group (-link-) attached thereto, the linking group (-link-) being covalently bonded to B; and   t is an integer equal to or greater than 1;   B is a biological substance, a synthetic substance which is capable of competing with a biological substance in a competitive binding reaction with a complementary material, or a non-biological polymer;   P, L 1 , and L 2  are such that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1 , and L 2 , and B are of such composition that the chemical moiety can be induced to emit electromagnetic radiation.   
   
   
       6 . A luminescent chemical reagent having the formula
   MPL 1 L 2 -(-link-)   wherein M is a lanthanide element;   L 1  and L 2  are ligands of M;   P is a bypyridyl or diketone-type polydentate ligand of M, wherein P has at least one linking group (-link-) attached thereto, the linking group (-link-) including an activator capable of reacting with a substance B to form a covalent bond linkage therewith; wherein B is a biological substance, a synthetic substance which is capable of competing with a biological substance in a competitive binding reaction with a complementary material, or a non-biological polymer;   P, L 1 , and L 2  are of such number that the total number of bonds to M provided by the ligands of M equals the coordination number of M; and   P, L 1 , and L 2  are of such composition that the luminescent chemical reagent can be induced to emit electromagnetic radiation.