Assay devices that utilize hollow particles

Abstract

Hollow particles for use in various types of assay devices are provided. Due to their hollow or voided structure, the particles may exhibit a variety of beneficial properties. For instance, hollow particles are generally lightweight, and thus, relatively inexpensive in comparison to other types of particles. Hollow particles may also form a stable system without requiring refrigeration or rotation. In addition, hollow particles may possess enhanced light diffraction capabilities, which may be particularly beneficial in certain types of assay devices, e.g., diffraction-based assay devices.

What is claimed is:  
     
         1 . An assay device comprising a plurality of detectable probes, wherein at least one of said detectable probes contains a particle that defines a hollow interior constituting from about 20% to about 100% of the spatial volume occupied by said particle.  
     
     
         2 . An assay device as defined in  claim 1 , wherein said hollow interior constitutes from about 30% to about 100% of the spatial volume occupied by said particle.  
     
     
         3 . An assay device as defined in  claim 1 , wherein the average size of said particle ranges from about 0.1 nanometers to about 1,000 microns.  
     
     
         4 . An assay device as defined in  claim 1 , wherein the average size of said particle ranges from about 0.1 nanometers to about 100 microns.  
     
     
         5 . An assay device as defined in  claim 1 , wherein the average size of said particle ranges from about 1 nanometer to about 10 microns.  
     
     
         6 . An assay device as defined in  claim 1 , wherein said particle has a spherical shape.  
     
     
         7 . An assay device as defined in  claim 1 , wherein said particle is formed from a polymer.  
     
     
         8 . An assay device as defined in  claim 7 , wherein said particle is formed from a core polymer and a shell polymer.  
     
     
         9 . An assay device as defined in  claim 1 , wherein said particle is formed by electrostatic layer deposition.  
     
     
         10 . An assay device as defined in  claim 1 , wherein said at least on detectable probe further contains a label.  
     
     
         11 . An assay device as defined in  claim 1 , wherein said particle is conjugated with a specific binding member.  
     
     
         12 . An assay device as defined in  claim 1 , wherein the assay device is a flow-through assay device.  
     
     
         13 . An assay device as defined in  claim 1 , wherein the assay device is a diffraction-based assay device.  
     
     
         14 . A flow-through assay device for detecting an analyte in a test sample, said flow-through assay device comprising a detection zone immobilized with a receptive material, said detection zone being in fluid communication with detection probes containing particles that individually define a hollow interior constituting from about 20% to about 100% of the spatial volume occupied by said particle, wherein said detection probes are capable of generating a detection signal while within said detection zone so that the amount of the analyte within the test sample is determined from said detection signal.  
     
     
         15 . A flow-through assay device as defined in  claim 14 , wherein said hollow interior constitutes from about 30% to about 100% of the spatial volume occupied by said particle.  
     
     
         16 . A flow-through assay device as defined in  claim 14 , wherein said particles are conjugated with a specific binding member for the analyte.  
     
     
         17 . A flow-through assay device as defined in  claim 14 , wherein said detection probes contain a label selected from the group consisting of chromogens, catalysts, fluorescent compounds, chemiluminescent compounds, phosphorescent compounds, radioactive compounds, direct visual labels, liposomes, and combinations thereof.  
     
     
         18 . A diffraction-based assay device for detecting an analyte of interest in a test sample, said assay device comprising: 
 a substrate having a receptive material applied to at least one surface thereof, said receptive material being specific for the analyte;    detection probes containing particles that individually define a hollow interior constituting from about 20% to about 100% of the spatial volume occupied by said particle; and    wherein upon exposing said substrate to the test sample, the analyte is capable of binding with said receptive material on said substrate to result in a detectable diffraction pattern upon subsequent exposure of said substrate to a light source.    
     
     
         19 . A diffraction-based assay device as defined in  claim 18 , wherein said hollow interior constitutes from about 30% to about 100% of the spatial volume occupied by said particle.  
     
     
         20 . A diffraction-based assay device as defined in  claim 18 , wherein said substrate is selected from the group consisting of plastics, metal coated plastics and glass, functionalized plastics and glass, silicon wafers, metal oxides, glass, foils, and combinations thereof.  
     
     
         21 . A diffraction-based assay device as defined in  claim 18 , wherein said substrate comprises a polymer film coated with a metal.  
     
     
         22 . A diffraction-based assay device as defined in  claim 21 , wherein said metal is selected from the group consisting of gold, silver, chromium, nickel, platinum, aluminum, iron, copper, titanium, zirconium, corresponding oxides of these metals, and combinations thereof.  
     
     
         23 . A diffraction-based assay device as defined in  claim 18 , wherein said receptive material is printed in a pattern on said substrate, and wherein a blocking material is further applied to non-printed areas of said substrate.  
     
     
         24 . A detectable probe for use in an assay device, wherein the detectable probe contains a particle that defines a hollow interior constituting from about 20% to about 100% of the spatial volume occupied by said particle, said particle being conjugated with a specific binding member.  
     
     
         25 . A detectable probe as defined in  claim 24 , wherein said hollow interior constitutes from about 30% to about 100% of the spatial volume occupied by said particle.  
     
     
         26 . A detectable probe as defined in  claim 24 , wherein the average size of said particle ranges from about 0.1 nanometers to about 1,000 microns.  
     
     
         27 . A detectable probe as defined in  claim 24 , wherein the average size of said particle ranges from about 0.1 nanometers to about 100 microns.  
     
     
         28 . A detectable probe as defined in  claim 24 , wherein the average size of said particle ranges from about 1 nanometer to about 10 microns.  
     
     
         29 . A detectable probe as defined in  claim 24 , wherein said particle has a spherical shape.  
     
     
         30 . A detectable probe as defined in  claim 24 , wherein said particle is formed from a polymer.  
     
     
         31 . A detectable probe as defined in  claim 30 , wherein said particle is formed from a core polymer and a shell polymer.  
     
     
         32 . A detectable probe as defined in  claim 24 , wherein said particle is formed by electrostatic layer deposition.  
     
     
         33 . A detectable probe as defined in  claim 24 , wherein said specific binding member is covalently bonded to said particle.