Coated water soluble nanoparticles

Abstract

Nanoparticles and methods of making nanoparticles are provided. The nanoparticles may include semiconductor nanocrystals. A shell may encapsulate a nanoparticle core, and the shell may include non-organic material and may be silica. The shell may also include additional species such as PEG. In some embodiments, a passivation layer is in contact with the core.

1 . A semiconductor nanocrystal solution comprising:
 an aqueous solution having a pH of less than about 8.0;   a plurality of semiconductor nanocrystals dissolved in the aqueous solution wherein at least 90% of the semiconductor nanocrystals, by weight, remain dissolved for greater than 6 hours.   
     
     
         2 . The semiconductor nanocrystal solution of  claim 1  wherein the aqueous solution is a biological fluid. 
     
     
         3 . The semiconductor nanocrystal solution of  claim 1  wherein the aqueous solution is mammalian blood. 
     
     
         4 . The semiconductor nanocrystal solution of  claim 1  wherein the aqueous solution has a pH of less than equal to 7.0. 
     
     
         5 . The semiconductor nanocrystal solution of  claim 1  wherein the semiconductor nanocrystals comprise polyethylene glycol. 
     
     
         6 . A semiconductor nanocrystal wherein the nanocrystal is soluble in water at a pH of less than about 8.0. 
     
     
         7 . The semiconductor nanocrystal of  claim 6  wherein the nanocrystal comprises a shell comprising silica. 
     
     
         8 . The semiconductor nanocrystal of  claim 7  wherein the shell includes a polyethylene glycol. 
     
     
         9 . The semiconductor nanocrystal of  claim 8  wherein the polyethylene glycol has a molecular weight of about 5,000 to 10,000. 
     
     
         10 . A nanoparticle comprising a silica shell encapsulating a core, the silica shell including polyethylene glycol, or a derivative thereof. 
     
     
         11 . The nanoparticle of  claim 10  wherein the polyethylene glycol has a molecular weight of about 5,000 to about 10,000.