Assay particles and methods of use

Abstract

The invention provides assay particles useful, for example, for detecting analytes and binding molecule interactions. One type of assay particle includes a core portion encased by a shell portion, wherein the shell portion comprises an inorganic phosphor that binds selectively to a target molecule. Another type of an assay particle includes a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor that binds selectively to a target molecule. A further type of assay particle includes a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor and a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media. An additional type of assay particle includes a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the shell portion comprises an inorganic phosphor and the coat portion comprises a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media. Also provided are kits and related methods.

1 . An assay particle, comprising a core portion encased by a shell portion, wherein the shell portion comprises an inorganic phosphor that binds selectively to a target molecule.  
     
     
         2 . The assay particle of  claim 1 , wherein the core portion comprises a material selected from the group of a gas, a liquid, a solid and a mixture thereof.  
     
     
         3 . The assay particle of  claim 1 , wherein the core portion comprises a material selected from the group of air, organic solvent and organic polymer.  
     
     
         4 . The assay particle of  claim 1 , wherein the assay particle is buoyant in aqueous media.  
     
     
         5 . The assay particle of  claim 1 , wherein the target molecule is a phosphorylated molecule.  
     
     
         6 . The assay particle of  claim 5 , wherein the inorganic phosphor is a hydrated metal oxide.  
     
     
         7 . The assay particle of  claim 1 , wherein the inorganic phosphor is selected from the group of rare-earth ion-doped yttrium oxide, rare-earth ion-doped zirconium oxide, rare-earth ion-doped yttrium oxysulfide and rare-earth ion-doped yttrium aluminum garnet.  
     
     
         8 . The assay particle of  claim 6 , wherein the rare-earth dopant is selected from the group of terbium (III), europium (III), dysprosium (III), samarium (III), ruthenium (II), rhenium (I) and a combination thereof.  
     
     
         9 . The assay particle of  claim 1 , wherein the particle has a density of less than 1 g/cm3.  
     
     
         10 . A method for detecting a target molecule, comprising: 
 contacting a sample suspected of containing the target molecule with an assay particle, wherein (i) the target molecule comprises a moiety capable of emitting radiation, and (ii) the assay particle comprises a shell portion comprising an inorganic phosphor capable of binding selectively to target molecules;    wherein binding of the target molecule to the inorganic phosphor produces a light signal, whereby the target molecule is detected.    
     
     
         11 . A method for detecting protein kinase activity, comprising: 
 contacting a sample containing a protein kinase with an assay particle, wherein the assay particle comprises a shell portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules, and a protein kinase substrate comprising a moiety capable of emitting radiation, under conditions wherein the protein kinase can phosphorylatethe substrate to produce a phosphorylated substrate,    wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal, and determining a protein kinase activity based on a level of detected phosphorylated substrate.    
     
     
         12 . A method for detecting protein phosphatase activity, comprising: 
 contacting a sample containing a protein phosphatase with an assay particle, wherein the assay particle comprises a shell portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules and wherein a protein phosphatase substrate comprising a moiety capable of emitting radiation is bound to the inorganic phosphor, under conditions wherein the protein phosphatase can dephosphorylate the substrate to produce a dephosphorylated substrate,    wherein phosphorylated substrate bound to the inorganic phosphor produces a light signal, and determining a phosphatase activity based on a level of detected phosphorylated substrate.    
     
     
         13 . A method for identifying a protein kinase modulator, comprising: 
 contacting a sample containing a protein kinase with (i) an assay particle comprising a shell portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules; and (ii) a substrate comprising a moiety capable of emitting radiation, in the presence and absence of a candidate compound, under conditions wherein the protein kinase can phosphorylate the substrate to produce a phosphorylated substrate, wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a protein kinase modulator.    
     
     
         14 . A method for identifying a cyclase modulator, comprising: 
 contacting a sample containing a cyclase with (i) an assay particle comprising a shell portion comprising an inorganic phosphor that is capable of binding selectively to non-cyclized nucleotides; and (ii) radioactively labeled non-cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the cyclase can acts on the substrate to produce cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a cyclase modulator.    
     
     
         15 . A method for identifying a phosphodiesterase modulator, comprising 
 contacting a sample containing a phosphodiesterase with (i) an assay particle comprising a shell portion comprising an inorganic phosphor that is capable of binding selectively to non-cyclized nucleotides; and (ii) radioactively labeled cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the phosphodiesterase can acts on the substrate to produce non-cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a phosphodiesterase modulator.    
     
     
         16 . A kit comprising an assay particle, comprising a core portion encased by a shell portion, wherein the shell portion comprises an inorganic phosphor that binds selectively to a target molecule, and an enzyme substrate comprising a moiety capable of emitting radiation.  
     
     
         17 . An assay particle, comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor that binds selectively to a target molecule.  
     
     
         18 . The assay particle of  claim 17 , wherein the core portion comprises a material selected from the group of a gas, a liquid, a solid and a mixture thereof.  
     
     
         19 . The assay particle of  claim 17 , wherein the core portion comprises a material selected from the group of air, organic solvent and organic polymer.  
     
     
         20 . The assay particle of  claim 17 , wherein the shell portion comprises a material selected from glass and ceramic.  
     
     
         21 . The assay particle of  claim 17 , wherein the assay particle is buoyant in aqueous media.  
     
     
         22 . The assay particle of  claim 17 , wherein the target molecule is a phosphorylated molecule.  
     
     
         23 . The assay particle of  claim 22 , wherein the inorganic phosphor is a hydrated metal oxide.  
     
     
         24 . The assay particle of  claim 17 , wherein the inorganic phosphor is selected from the group of rare-earth ion-doped yttrium oxide, rare-earth ion-doped zirconium oxide, rare-earth ion-doped yttrium oxysulfide and rare-earth ion-doped yttrium aluminum garnet.  
     
     
         25 . The assay particle of  claim 24 , wherein the rare-earth dopant is selected from the group of terbium (III), europium (III), dysprosium (III), samarium (III), ruthenium (II), rhenium (I) and a combination thereof.  
     
     
         26 . The assay particle of  claim 17 , wherein the particle has a density of less than 1 g/cm3.  
     
     
         27 . A method for detecting a target molecule, comprising 
 contacting a sample suspected of containing the target molecule with an assay particle of  claim 17 , wherein (i) the target molecule comprises a moiety capable of emitting radiation, and (ii) the assay particle comprises a coat portion comprising an inorganic phosphor capable of binding selectively to target molecules;    wherein binding of the target molecule to the inorganic phosphor produces a light signal, whereby the target molecule is detected.    
     
     
         28 . A method for detecting protein kinase activity, comprising 
 contacting a sample containing a protein kinase with an assay particle of  claim 17 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules, and a protein kinase substrate comprising a moiety capable of emitting radiation, under conditions wherein the protein kinase can phosphorylatethe substrate to produce a phosphorylated substrate,    wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal, and determining a protein kinase activity based on a level of detected phosphorylated substrate.    
     
     
         29 . A method for detecting protein phosphatase activity, comprising 
 contacting a sample containing a protein phosphatase with an assay particle of  claim 17 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules and a protein phosphatase substrate comprising a moiety that is capable of emitting radiation is bound to the inorganic phosphor, under conditions wherein the protein phosphatase can dephosphorylate the substrate to produce a dephosphorylated substrate,    wherein phosphorylated substrate bound to the inorganic phosphor produces a light signal, and determining a phosphatase activity based on a level of detected phosphorylated substrate.    
     
     
         30 . A method for identifying a protein kinase modulator, comprising 
 contacting a sample containing a protein kinase with (i) an assay particle of  claim 17  comprising a coat portion comprising an inorganic phosphor that is capable of binding selectively to phosphorylated molecules; and (ii) a substrate capable of emitting radiation, in the presence and absence of a candidate compound, under conditions wherein the protein kinase can phosphorylate the substrate to produce a phosphorylated substrate, wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a protein kinase modulator.    
     
     
         31 . A method for identifying a cyclase modulator, comprising: 
 contacting a sample containing a cyclase with (i) an assay particle of  claim 17  comprising a coat portion comprising an inorganic phosphor that is capable of binding selectively to non-cyclized nucleotides; and (ii) radioactively labeled non-cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the cyclase can acts on the substrate to produce cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a cyclase modulator.    
     
     
         32 . A method for identifying a phosphodiesterase modulator, comprising: 
 contacting a sample containing a phosphodiesterase with (i) an assay particle of  claim 17  comprising a coat portion comprising an inorganic phosphor that is capable of binding selectively to non-cyclized nucleotides; and (ii) radioactively labeled cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the phosphodiesterase can acts on the substrate to produce non-cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a phosphodiesterase modulator.    
     
     
         33 . A kit comprising an assay particle of  claim 17 , comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor that binds selectively to a target molecule, and an enzyme substrate capable of emitting radiation.  
     
     
         34 . An assay particle, comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor and a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media.  
     
     
         35 . The assay particle of  claim 34 , wherein the core portion comprises a material selected from the group of a gas, a liquid, a solid and a mixture thereof.  
     
     
         36 . The assay particle of  claim 34 , wherein the core portion comprises a material selected from the group of air, organic solvent and organic polymer.  
     
     
         37 . The assay particle of  claim 34 , wherein the core portion comprises a material selected from the group of air, organic solvent and organic polymer.  
     
     
         38 . The assay particle of  claim 34 , wherein the shell portion comprises a material selected from the group of glass, ceramic and polymer.  
     
     
         39 . The assay particle of  claim 34 , wherein the inorganic phosphor is selected from the group of rare-earth ion-doped yttrium oxide, rare-earth ion-doped zirconium oxide, rare-earth ion-doped yttrium oxysulfide and rare-earth ion-doped yttrium aluminum garnet.  
     
     
         40 . The assay particle of  claim 39 , wherein the rare-earth dopant is selected from the group of terbium (III), europium (III), dysprosium (III), samarium (III), ruthenium (II), rhenium (I) and a combination thereof.  
     
     
         41 . The assay particle of  claim 34 , wherein the target selective binding agent is selected from the group of antibody, aptamer, protein A, protein G, streptavidin, avidin, captavidin, neutravidin, metal chelate, siderophore, lectin, and an oligonucleotide.  
     
     
         42 . The assay particle of  claim 34 , wherein the particle has a density of less than 1 g/cm 3 .  
     
     
         43 . A method for detecting a target molecule, comprising 
 contacting a sample suspected of containing the target molecule with an assay particle of  claim 34 , wherein (i) the target molecule comprises a moiety capable of emitting radiation, and (ii) the assay particle comprises a coat portion comprising an inorganic phosphor and a target selective binding agent, and is buoyant in aqueous media;    wherein binding of the target molecule to the target selective binding agent activates the inorganic phosphor to produce a light signal, whereby the target molecule is detected.    
     
     
         44 . A method for detecting protein kinase activity, comprising 
 contacting a sample containing a protein kinase with (i) an assay particle of  claim 34 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor and a binding agent selective for phosphorylated molecules, and is buoyant in aqueous media; and (ii) a protein kinase substrate comprising a moiety capable of emitting radiation, under conditions wherein the protein kinase can phosphorylatethe substrate to produce a phosphorylated substrate,    wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal, and determining a protein kinase activity based on a level of detected phosphorylated substrate.    
     
     
         45 . A method for detecting protein phosphatase activity, comprising 
 contacting a sample containing a protein phosphatase with an assay particle of  claim 34 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor and a binding agent selective for phosphorylated molecules, and wherein a protein phosphatase substrate comprising a moiety capable of emitting radiation is bound to the inorganic phosphor, under conditions wherein the protein phosphatase can dephosphorylate the substrate to produce a dephosphorylated substrate,    wherein phosphorylated substrate bound to the inorganic phosphor produces a light signal, and determining a phosphatase activity based on a level of detected phosphorylated substrate.    
     
     
         46 . A method for identifying a protein kinase modulator, comprising 
 contacting a sample containing a protein kinase with (i) an assay particle of  claim 34 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor and a binding agent selective for phosphorylated molecules; and (ii) a substrate comprising a moiety capable of emitting radiation, in the presence and absence of a candidate compound, under conditions wherein the protein kinase can phosphorylate the substrate to produce a phosphorylated substrate, wherein binding of the phosphorylated substrate to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a protein kinase modulator.    
     
     
         47 . A method for identifying a cyclase modulator, comprising contacting a sample 
 containing a cyclase with (i) an assay particle, wherein the assay particle of  claim 34  comprises a coat portion comprising an inorganic phosphor and a binding agent selective for non-cyclized nucleotides ; and (ii) radioactively labeled non-cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the cyclase can acts on the substrate to produce cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a cyclase modulator.    
     
     
         48 . A method for identifying a phosphodiesterase modulator, comprising 
 contacting a sample containing a phosphodiesterase with (i) an assay particle of  claim 34 , wherein the assay particle comprises a coat portion comprising an inorganic phosphor and a binding agent selective for non-cyclized nucleotides; and (ii) radioactively labeled cyclized nucleotide, in the presence and absence of a candidate compound, under conditions wherein the phosphodiesterase can acts on the substrate to produce non-cyclized nucleotides, wherein binding of the non-cyclized nucleotide to the inorganic phosphor produces a light signal; and    detecting light signals produced in the presence and absence of the candidate compound, wherein a difference in light signals produced in the presence and absence of the compound identifies the compound as a phosphodiesterase modulator.    
     
     
         49 . A kit comprising an assay particle of  claim 34 , comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor and a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media, and an enzyme substrate capable of emitting radiation.  
     
     
         50 . An assay particle, comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the shell portion comprises an inorganic phosphor and the coat portion comprises a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media.  
     
     
         51 . A method for detecting a target molecule, comprising use of the assay particle of  claim 50 .  
     
     
         52 . A kit comprising an assay particle of  claim 50 , comprising a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the shell portion comprises an inorganic phosphor and the coat portion comprises a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media, and an enzyme substrate capable of emitting radiation.