Stable Metal/Conductive Polymer Composite Colloids and Methods for Making and Using the Same

Abstract

Stable metal/conductive polymer composite colloids and methods for making the same are provided. The subject colloids find use in a variety of different applications, including analyte detection applications. Also provided are kits that include the subject colloids.

1 - 32 . (canceled) 
     
     
         33 . A stable metal/conductive polymer composite colloid comprising metal particles surface coated with a water-soluble conductive polymer layer and suspended in an aqueous medium. 
     
     
         34 . The composite colloid according to  claim 33 , wherein said colloid is uniform with respect to said polymer coated particles. 
     
     
         35 . The composite colloid according to  claim 33 , wherein said water-soluble conductive polymer layer is present as a monolayer of polymer molecules surface adsorbed to said metal particles. 
     
     
         36 . The composite colloid according to  claim 33 , wherein said metal particles have a diameter ranging from about 2 nm to about 1,200 nm. 
     
     
         37 . The composite colloid according to  claim 36 , wherein said composite colloid has a particle density ranging from about 1.01 to about 1.30. 
     
     
         38 . The composite colloid according to  claim 33 , wherein said metal particles and said water-soluble conductive polymer are matched in terms of at least one optical property. 
     
     
         39 . The composite colloid according to  claim 38 , wherein said optical property is an absorbance maximum. 
     
     
         40 . The composite colloid according to  claim 33 , wherein said water-soluble composite colloid is more sensitive to changes in refractive index of said medium as compared to a control colloid comprising said metal particles not coated with said conductive polymer. 
     
     
         41 . The composite colloid according to  claim 33 , wherein said metal particles comprise a noble metal. 
     
     
         42 . The composite colloid according to  claim 41 , wherein said noble metal is chosen from gold and silver. 
     
     
         43 . The composite colloid according to  claim 33 , wherein said water-soluble conductive polymer is an organic polymer. 
     
     
         44 . The composite colloid according to  claim 43 , wherein said organic polymer comprises ionizable moieties. 
     
     
         45 . The composite colloid according to  claim 44 , wherein said ionizable moieties are carboxylic acid moieties. 
     
     
         46 . The composite colloid according to  claim 33 , wherein said water-soluble conductive polymer is a substituted polyaniline. 
     
     
         47 . The composite colloid according to  claim 46 , wherein said substituted polyaniline is poly(aniline-2-carboxylic acid). 
     
     
         48 . The composite colloid according to  claim 33 , wherein said particles of said metal/conductive polymer composite colloid comprise a surface-immobilized ligand. 
     
     
         49 . The composite colloid according to  claim 48 , wherein said ligand is a nucleic acid. 
     
     
         50 . The composite colloid according to  claim 48 , wherein said ligand is a peptide. 
     
     
         51 . The composite colloid according to  claim 48 , wherein said ligand is a small molecule. 
     
     
         52 . The composite colloid according to  claim 51 , wherein said small molecule is an organic molecule. 
     
     
         53 . The composite colloid according to  claim 51 , wherein said small molecule is an inorganic molecule. 
     
     
         54 . The composite colloid according to  claim 48 , wherein said ligand is bound to said particle by a linker. 
     
     
         55 . A stable metal/conductive polymer composite colloid comprising metal particles surface coated with a water-soluble conductive polymer layer and suspended in an aqueous medium, where said particles comprise a surface-immobilized ligand and said metal particles and conductive polymer are matched in terms of at least one optical property. 
     
     
         56 . The composite colloid according to  claim 55 , wherein said colloid is uniform with respect to said polymer coated particles. 
     
     
         57 . The composite colloid according to  claim 55 , wherein said water-soluble conductive polymer layer is present as a monolayer of polymer molecules surface adsorbed to said metal particles. 
     
     
         58 . The composite colloid according to  claim 55 , wherein said metal particles have a diameter ranging from about 1 to about 1,000 nm. 
     
     
         59 . The composite colloid according to  claim 58 , wherein said composite colloid has a particle density ranging from about 1.01 to about 1.30. 
     
     
         60 . (canceled) 
     
     
         61 . The composite colloid according to  claim 55 , wherein said optical property is an absorbance maximum. 
     
     
         62 . The composite colloid according to  claim 55 , wherein said composite colloid is more sensitive to changes in refractive index of said medium as compared to a control colloid comprising said metal particles not coated with said water-soluble conductive polymer. 
     
     
         63 . The composite colloid according to  claim 55 , wherein said metal particles comprise a noble metal. 
     
     
         64 . The composite colloid according to  claim 62 , wherein said water-soluble conductive polymer is an organic polymer. 
     
     
         65 . The composite colloid according to  claim 64 , wherein said organic polymer comprises ionizable moieties. 
     
     
         66 . The composite colloid according to  claim 65 , wherein said ionizable moieties are carboxylic acid moieties. 
     
     
         67 . The composite colloid according to  claim 55 , wherein said conductive polymer is a substituted polyaniline. 
     
     
         68 . The composite colloid according to  claim 67 , wherein said substituted polyaniline is poly(aniline-2-carboxylic acid). 
     
     
         69 . The composite colloid according to  claim 55 , wherein said ligand is a nucleic acid. 
     
     
         70 . The composite colloid according to  claim 55 , wherein said ligand is a peptide. 
     
     
         71 . The composite colloid according to  claim 55 , wherein said ligand is a small molecule. 
     
     
         72 . The composite colloid according to  claim 71 , wherein said small molecule is an organic molecule. 
     
     
         73 . The composite colloid according to  claim 71 , wherein said small molecule is an inorganic molecule. 
     
     
         74 . The composite colloid according to  claim 55 , wherein said ligand is bound to said particle by a linker. 
     
     
         75 . A method for screening a sample for the presence of an analyte, said method comprising:
 (a) contacting said sample with a stable metal/conductive polymer composite colloid to produce an assay mixture, wherein said colloid metal particles are surface coated with a water-soluble conductive polymer layer and comprise a surface-immobilized ligand that specifically binds to said analyte; and   (b) detecting an optical parameter of said assay mixture to screen said sample for the presence of said analyte.   
     
     
         76 . The method according to  claim 75 , wherein said method is qualitative. 
     
     
         77 . The method according to  claim 75 , wherein said method is quantitative. 
     
     
         78 . The method according to  claim 75 , wherein said analyte is a nucleic acid. 
     
     
         79 . The method according to  claim 75 , wherein said analyte is a peptide. 
     
     
         80 . The method according to  claim 75 , wherein said analyte is a gaseous analyte. 
     
     
         81 . The method according to  claim 75 , wherein said optical parameter is a change in light absorbance. 
     
     
         82 . A kit for detecting the presence of an analyte in a sample, said kit comprising:
 a stable metal/conductive polymer composite colloid comprising metal particles surface coated with a water-soluble conductive polymer layer and comprising a surface-immobilized ligand that specifically binds to said analyte.   
     
     
         83 . The composite colloid of  claim 39 , wherein the absorbance maximum of said metal particles and said water-soluble conductive polymer differ by less than about 50 nm.