Polymeric microspheres

Abstract

The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

1 . A hollow microsphere comprising a polymeric shell, wherein the thickness of said shell varies less than 10%. 
   
   
       2 . The microsphere of  claim 1 , wherein said shell thickness varies less than 5%. 
   
   
       3 . The microsphere of  claim 1 , wherein said shell thickness varies less than 1%. 
   
   
       4 . The microsphere of  claim 1 , wherein said shell thickness varies less than 0.5%. 
   
   
       5 . The microsphere of  claim 1 , wherein said shell thickness is in the range of 100-1000 nm. 
   
   
       6 . The microsphere of  claim 1 , wherein said shell thickness is in the range of 150-250 nm. 
   
   
       7 . The microsphere of  claim 1 , wherein said shell thickness is in the range of 350-450 nm. 
   
   
       8 . The microsphere of  claim 1 , wherein said shell thickness is in the range of 550-650 m. 
   
   
       9 . The microsphere of  claim 1 , wherein said microsphere is substantially devoid of silica. 
   
   
       10 . The microsphere of  claim 1 , wherein said microsphere comprises a pore, said pore having a size in the range of 10 -500 nm. 
   
   
       11 . The microsphere of  claim 1 , wherein said microsphere comprises an organic dye. 
   
   
       12 . The microsphere of  claim 11 , wherein said dye is an Azo dye. 
   
   
       13 . The microsphere of  claim 11 , wherein said dye is selected from the group consisting of Indigo Blue, Lissamine Green B, VAT Green 1, VAT Yellow 4, VAT Violet 1, Anthrasol, Blue IBC, Indigosol Pink IR, Indigosol Grey IBL, Anthrasol Brown IBR, and Red 146. 
   
   
       14 . The microsphere of  claim 1 , wherein said microsphere comprises a protecting agent. 
   
   
       15 . The microsphere of  claim 1 , wherein said microsphere comprises a therapeutic agent. 
   
   
       16 . The microsphere of  claim 15 , wherein said therapeutic agent is selected from the group consisting of a polypeptide, an antibody, an enzyme, a nucleic acid, and a small molecule drug. 
   
   
       17 . The microsphere of  claim 1 , wherein said shell comprises an acrylate polymer, a methacrylate polymer, or a styrene polymer. 
   
   
       18 . The microsphere of  claim 1 , wherein said shell comprises a polymer of one or more monomers selected from the group consisting of acrylonitrile, styrene, benzyl methacrylate, phenyl methacrylate, ethyl methacrylate, divinyl benzene, 2-Hydroxyethyl methacrylate, cyclohexyl methacrylate, p-methyl styrene, acrylamide, methacrylamide, methacrylonitrile, hydroxypropyl methacrylate, methoy styrene, N-acrylylglycinamide, and N-methacrylylglycinamide. 
   
   
       19 . The microsphere of  claim 1 , wherein said shell comprises a co-polymer selected from the group consisting of styrene-PMMA, benzyl methacrylate-PMMA, styrene-PHEMA, styrene-PEMA, styrene-methacrylate, and styrene-butylacrylate. 
   
   
       20 . The microsphere of  claim 1 , wherein said polymeric shell comprises a cross-linked polymer. 
   
   
       21 . The microsphere of claim l, wherein the microsphere is prepared by a method comprising:
 providing a substrate comprising a plurality of hydroxyl groups;   attaching an initiator agent to said hydroxyl groups to form attached initiator agents;   reacting the attached initiator agents with a polymerizable unit under living polymerization conditions to form a polymer shell over said substrate, said polymerization being confined to a surface of said substrate; and   exposing said substrate to an etching agent for a time sufficient to allow for removal of said substrate from said polymeric shell to form a hollow microsphere.   
   
   
       22 . The microsphere of  claim 1 , wherein the microsphere is prepared by a method comprising:
 providing a microsphere substrate;   contacting said microsphere substrate with a polymer nanosphere to yield a colloidal assembly;   heating said assembly to yield a core-shell composite; and   exposing said composite to an etching agent for a time sufficient to allow for removal of said core from said shell to form a hollow microsphere.