Synthesis of highly luminescent colloidal particles

Abstract

The present invention includes compositions and methods for their used wherein the compositions include clusters of coated fluorescent nanocrystals having a select size formed by controlled aggregation of individual coated nanocrystals.

1 . A composition comprising an aggregate of nanocrystals; wherein: 
 the nanocrystals comprise a coating layer;    the coating layer comprises one or more imidazole groups; and    the nanocrystals interact through the coating layer to form the aggregate.    
     
     
         2 . The composition of  claim 1 , wherein the aggregate is cross linked.  
     
     
         3 . The composition of  claim 2 , wherein a cross linking agent is used to cross link the aggregate.  
     
     
         4 . The composition of  claim 3 , wherein the cross linking agent is tris(hydroxy methyl) phosphine.  
     
     
         5 . The composition of  claim 3 , wherein the cross linking agent is beta-[tris (hydroxymethyl)phosphino]propionic acid.  
     
     
         6 . The composition of  claim 1 , wherein the coating layer is bound to the nanocrystal by the one or more imidazole groups.  
     
     
         7 . The composition of  claim 1 , wherein the aggregated nanocrystals are crosslinked by one or more organophosphine compounds.  
     
     
         8 . The composition of  claim 1 , wherein the nanocrystals are luminescent.  
     
     
         9 . The composition of  claim 1 , wherein the nanocrystals are fluorescent.  
     
     
         10 . The composition of  claim 1 , wherein the aggregate is dispersed in an aqueous based solution.  
     
     
         11 . The composition of  claim 1 , wherein the aggregate further comprises at least one functional group on the surface of the aggregate.  
     
     
         12 . The composition of  claim 1 , wherein the aggregate further comprises a functional group selected from the group consisting of a hydroxyl, thiol, amino, acetylenic, carboxyl, ester, amide, dicarboxylic, carboxamide selenol, hydrazide, aldehyde and a combination thereof on the surface of the coated nanocrystal aggregate.  
     
     
         13 . The composition of  claim 1 , wherein the nanocrystals are semiconductor core nanocrystals.  
     
     
         14 . The composition of  claim 1 , wherein the nanocrystals are semiconductor core/shell nanocrystals.  
     
     
         15 . The composition of  claim 1 , wherein the coating layer comprises histidine, carnosine, polyhistidine, polyimidazole, or glycyl histidine.  
     
     
         16 . A composition comprising a nanocrystal aggregate and at least one affinity molecule; wherein: 
 the aggregate comprises two or more coated nanocrystals;    the nanocrystals comprise a coating layer comprising one or more imidazole groups;    the nanocrystals interact through the coating layer to form the aggregate;    the aggregate comprises at least one functional group on its surface; and    the at least one affinity molecule is linked to the functional group.    
     
     
         17 . The composition of  claim 16 , wherein the affinity molecule is selected from the group consisting of a polyclonal antibody, a monoclonal antibody, a peptide, an aptamer, a nucleic acid, a lectin, a lipid, a small organic molecule, a polysaccharide, avidin, neutravidin, streptavidin, an avidin derivative, biotin, a biotin derivative, and combinations thereof.  
     
     
         18 . The composition of  claim 16 , wherein the affinity molecule is covalently linked to the functional group.  
     
     
         19 . The composition of  claim 16 , wherein the functional group is selected from the group consisting of a hydroxyl, thiol, amino, acetylenic, carboxyl, ester, amide, dicarboxylic, carboxamide selenol, hydrazide, aldehyde and a combination thereof.  
     
     
         20 . A composition comprising two to about twenty aggregated fluorescent semiconductor nanocrystals; wherein: 
 the fluorescent nanocrystals comprise a coating layer;    the coating layer comprises one or more imidazole groups; and    the nanocrystals interact through their coating layers to form an aggregate, the aggregate being composed of from about two to about twenty fluorescent semiconductor nanocystals.    
     
     
         21 . The composition of  claim 20 , wherein the nanocrystals are crosslinked by an organophosphine compound in the aggregate.  
     
     
         22 . A method of preparing a nanocrystal aggregate, the method comprising: 
 contacting two or more nanocrystals in a solvent, the nanocrystals comprising a coating layer comprising at least one imidazole group; and    contacting the nanocrystals to prepare an aggregate of coated nanocystals.    
     
     
         23 . The method of  claim 22 , further comprising controlling the aggregate size by modifying the solvent.  
     
     
         24 . The method of  claim 22 , wherein the nanocrystals interact through their coating layers.  
     
     
         25 . The method of  claim 22 , wherein the contacting step further comprises placing the two or more nanocrystals in a solvent mixture.  
     
     
         26 . The method of  claim 22 , wherein the contacting step further comprises placing the two or more nanocrystals in an aqueous solvent mixture.  
     
     
         27 . A method of detecting a target molecule in a sample, the method comprising: 
 providing a sample suspected of containing a target molecule;    providing one or more coated nanocrystal aggregates, said coated nanocrystal aggregates comprising a nanocrystal, an imidazole containing coating, and an affinity ligand having binding specificity for the target molecule;    contacting the sample and the aggregates to form a treated sample, wherein the aggregates form a complex with the target molecule;    exciting the complex with a wavelength of energy to form an excited complex; and detecting the excited complex.    
     
     
         28 . The method of  claim 27 , where the detecting step comprises detecting light emitted by the excited complex.  
     
     
         29 . The method of  claim 27 , where the detecting step comprises using a Scintillation Proximity assay.  
     
     
         30 . The method of  claim 27 , where the detecting step further comprises quantifying the amount of target molecule in the sample.  
     
     
         31 . The method of  claim 27 , wherein the wavelength is less than about 500 nm.