Novel chemistry used in biosensors

Abstract

The invention relates to novel compositions and methods for the detection of analytes using the nuclear reorganization energy, λ, of an electron transfer process.

1 . A composition comprising 1) an electrode comprising a covalently attached electroactive complex (EAM), said EAM comprising a transition metal and at least one cyano ligand; or 2) an electrode comprising a) a first species comprising a functional group, and b) an EAM, said EAM comprising a transition metal and at least one cyano ligand; or 3) a) a first anchor, b) a charge-neutralizing ligand linked to said first anchor, c) an EAM covalently attached to said charge-neutralizing ligand, and d) a capture ligand; or 4) an electrode comprising a self-assembled monolayer (SAM), wherein said SAM comprises a compound having the formula: Anchor-Spacer 1-EAM-Spacer 2-CL (II), wherein said anchor is linked to said electrode group through a disulfide group, EAM is an electroactive moiety comprising a solvent accessible redox compound, CL is a capture ligand, Spacer 1 is either insulating or conducting, and Spacer 2 is optional; or 5) an array of electrode, each electrode comprising a compound having the formula: Anchor-Spacer 1-EAM-(Spacer 2) n -CL (I), wherein said anchor comprises a cyclic-disulfide group, EAM is an electroactive moiety comprising a solvent accessible redox compound, CL is a capture ligand, Spacer 1 is either insulating or conduction, and n=0 or 1. 
     
     
         2 . The composition according to  claim 1 , wherein said EAM of 1) comprises at least two cyano ligands. 
     
     
         3 . The composition according to  claim 1 , wherein said EAM of 1) comprises at least three cyano ligands. 
     
     
         4 . The composition according to  claim 1 , wherein said EAM of 1) comprises at least four cyano ligands. 
     
     
         5 . The composition according to  claim 1 , wherein said EAM of 1) comprises at least five cyano ligands. 
     
     
         6 . The composition according to  claim 1 , wherein said transition metal of 1) is osmium. 
     
     
         7 . The composition according to  claim 1 , wherein said electrode of 1) is gold and said EAM of 1) is covalently attached to said electrode via a sulfur atom. 
     
     
         8 . The composition according to  claim 1 , wherein said electrode of 1) is gold and said EAM of 1) is covalently attached to said electrode via two sulfur atoms. 
     
     
         9 . The composition according to  claim 7 , wherein said EAM is attached to said electrode using an attachment linker with a first terminus comprising said sulfur atom(s). 
     
     
         10 . The composition according to  claim 7 , wherein said attachment linker comprises a second terminus that provides a coordination atom for said transition metal. 
     
     
         11 . The composition according to  claim 9 , wherein said attachment linker is an alkyl chain. 
     
     
         12 . The composition according to  claim 11 , wherein said alkyl chain is substituted. 
     
     
         13 . The composition according to  claim 1 , wherein said electrode of 1) comprises a redox active capture complex (REAMC) comprising said EAM and a capture ligand. 
     
     
         14 . The composition according to  claim 13 , wherein said capture ligand provides a coordination atom for said transition metal. 
     
     
         15 . The composition according to  claim 13 , wherein electrode is gold and said REAMC is covalently attached to said electrode via a sulfur atom. 
     
     
         16 - 24 . (canceled) 
     
     
         25 . A method of detecting a target enzyme comprising:
 a) contacting a sample with a composition comprising an electrode comprising:
 i) an electroactive moiety (EAM) comprising a transition metal and at least one cyano ligand with a first E 0 ; 
 ii) a capture ligand; 
   
       under conditions whereby said target enzyme, if present, alters said capture ligand such that said EAM has a second E 0 ; and
 b) measuring said second E 0 ; or 
 a) contacting a sample with a composition comprising a REAMC comprising:
 i) an electroactive moiety (EAM) comprising a transition metal and at least one cyano ligand with a first E 0 ; and 
 ii) a capture ligand; under conditions whereby said target enzyme, if present, alters said capture ligand such that said EAM has a second E 0 ; and 
 
 b) measuring said second E 0 . 
 
     
     
         26 - 29 . (canceled) 
     
     
         30 . A method of making a biosensor comprising:
 a) providing an electrode comprising:
 i) a first species comprising a first functional group; and 
 ii) an electroactive complex (EAM), said EAM comprising a transition metal and 
   at least one cyano ligand; and   c) contacting said electrode with a biomolecule comprising a second functional group to form a covalent bond between said first species and said biomolecule.   
     
     
         31 - 33 . (canceled) 
     
     
         34 . A compound having the formula:
   Anchor-Spacer 1-EAM-(Spacer 2) n —CL  (I)
   wherein said anchor comprises a cyclic-disulfide group,
 EAM is an electroactive moiety comprises a solvent accessible redox compound, 
 CL is a capture ligand, 
   Spacer 1 is a SAM forming species, and
 n=0 or 1; or
   Anchor-Spacer 1-EAM-(Spacer 2) n —CL  (I)
 
 
   wherein said anchor comprises a pyridyl group,
 EAM is an electroactive moiety comprises: 
 i) a solvent accessible redox compound, and 
 ii) a charge-neutralizing ligand, 
 CL is a capture ligand, 
 Spacer 1 is a SAM forming species, and 
 n=0 or 1. 
   
     
     
         35 - 46 . (canceled) 
     
     
         47 . A method, comprising:
 a) providing a compound having the formula:
   Anchor-Spacer 1-EAM-(Spacer 2) n —CL  (I),
 
   
       wherein said anchor comprises a cyclic-disulfide group,
 EAM is an electroactive moiety comprises a solvent accessible redox compound, 
 CL is a capture ligand, 
 Spacer 1 is either insulating or conduction, 
 and n=0 or 1; and 
 b) contacting said compound to an electrode by opening said cyclic disulfide to form an attachment of said anchor to said electrode. 
 
     
     
         48 - 49 . (canceled) 
     
     
         50 . A method of detecting a target analyte in a test sample, comprising:
 a) providing an electrode comprises a compound having the formula:
   Anchor-Spacer 1-EAM-(Spacer 2) n —CL  (I)
 
   
       wherein said anchor comprises a cyclic-disulfide group,
 EAM is an electroactive moiety comprises a solvent accessible redox compound, 
 CL is a capture ligand, 
 Spacer 1 is either insulating or conduction, and 
 n=0 or 1; and 
 b) contacting said electrode with said test sample; and 
 c) determining the presence of said target analyte by measuring the reorganization energy of said EAM.