Biofunctionalized quantum dots for biological imaging

Abstract

Novel biofunctionalized quantum dots include a mercaptoalkanoic acid linked to the surface of a nanocrystalline core and a biofunctional group linked to the surface. Biofunctionalized quantum dots are made by a novel synthesis method. Biofunctionalized quantum dots can be used in imaging or therapy applications.

1 . A biofunctionalized quantum dot, comprising:
 a nanocrystalline core exhibiting quantum confinement and having a band gap and a surface;   a mercaptoalkanoic acid linked to the surface; and   a biofunctional group linked to the surface,   wherein the biofunctional group comprises a saccharide or the mercaptoalkanoic acid is linked to the surface of the nanocrystalline core without a shell layer.   
     
     
         2 . The biofunctionalized quantum dot of  claim 1 ,
 the mercaptoalkanoic acid having exactly one carboxyl group and comprising less than seven carbon atoms.   
     
     
         3 . The biofunctionalized quantum dot of  claim 1 ,
 the mercaptoalkanoic acid comprising mercaptoacetic acid.   
     
     
         4 . The biofunctionalized quantum dot of  claim 1 , further comprising:
 a shell layer overcoating the nanocrystalline core.   
     
     
         5 . The biofunctionalized quantum dot of  claim 4 ,
 the shell layer comprising cadmium sulfide or mercury sulfide; and   the nanocrystalline core comprising cadmium telluride or cadmium selenide or mercury telluride or mercury selenide.   
     
     
         6 . The biofunctionalized quantum dot of  claim 1 ,
 the saccharide not comprising mannose or dextran.   
     
     
         7 . The biofunctionalized quantum dot of  claim 1 ,
 the saccharide being selected from the group consisting of a tumor-associated antigen and Thomsen-Friedenreich disaccharide.   
     
     
         8 . The biofunctionalized quantum dot of  claim 1 ,
 the saccharide linked to a sulfur atom; and   the sulfur atom linked to the surface of the nanocrystalline core.   
     
     
         9 . The biofunctionalized quantum dot of  claim 1 ,
 the saccharide linked to a linking group;   the linking group linked to a sulfur atom; and   the sulfur atom linked to the surface of the nanocrystalline core.   
     
     
         10 . The biofunctionalized quantum dot of  claim 9 ,
 the linking group comprising a carbon atom.   
     
     
         11 . The biofunctionalized quantum dot of  claim 1 , wherein the biofunctionalized quantum dot is stable in aqueous solution under storage in the dark at 4° C. for at least 4 months with respect to luminescence, precipitation, flocculation, and leaching of the biofunctional group.