Cell-free biofragment compositions and related systems, devices, and methods

Abstract

The present disclosure relates to biofragment compositions that comprise bioparticle fragments and at least one heterologous antigen-binding molecule. In some embodiments, the biofragment is typically derived from a larger, intact bioparticle that express the at least one heterologous antigen-binding molecule at the surface, and the biofragment has increased solubility to facilitate assays for antigen detection. The disclosure also relates the related methods of using and making the biofragment compositions, as well as systems and devices implementing the biofragment compositions. In some embodiments, the related methods, systems and devices do not require additional detection reagents, such as animal derived detection antibodies.

1 - 12 . (canceled) 
     
     
         13 . A method of detecting the presence of an antigen of interest in a biological sample, comprising:
 1) contacting a biological sample with a biofragment composition under conditions sufficient to permit the binding of the composition with an antigen of interest, wherein the biofragment composition comprises a surface fragment of a ruptured cell or cellular organelle, wherein the surface fragment displays at least one antigen-binding molecule heterologous to the cell or cellular organelle, and wherein the antigen-binding molecule selectively binds the antigen of interest; and   2) detecting the binding of the biofragment composition to the antigen of interest.   
     
     
         14 . The method of  claim 13 , wherein the biofragment composition is immobilized to a surface. 
     
     
         15 . The method of  claim 13 , further comprising contacting the biological sample with a detection reagent that binds to the antigen of interest. 
     
     
         16 . The method of  claim 15 , further comprising contacting the biological sample with a detectably-labeled reporter reagent and separating the unbound reporter from the biofragment composition. 
     
     
         17 . The method of  claim 13 , wherein binding of the antigen of interest to the biofragment composition is detected using an antibody sandwich flow cytometric assay, cell bioprobe immunofluorescence microscopy, an ELISA-like assay, or a competitive inhibition assay. 
     
     
         18 . The method of  claim 14 , wherein the biofragment composition is immobilized, directly or indirectly, to a conductive or semi-conductive electrode surface. 
     
     
         19 . The method of  claim 18 , further comprising providing an electroactive molecule and measuring the electron transfer resistance at the electrode surface, wherein binding of the antigen of interest to the biofragment composition is detected by a change in the electron transfer resistance as compared to the electron transfer resistance when the antigen of interest is not present. 
     
     
         20 . The method of  claim 13 , wherein the biological sample is selected from the group consisting of blood, urine, sputum, mucus, saliva, cerebral spinal fluid, tissues, stool, nutrient sources, environmental sample, or a processed derivative thereof. 
     
     
         21 . The method of  claim 13 , further comprising:
 1) contacting the biological sample with a capture reagent that binds to the antigen of interest; and   2) contacting the biological sample with the biofragment composition configured as a detection reagent.   
     
     
         22 . The method of  claim 21 , wherein the detection reagent further comprises a detectable label. 
     
     
         23 . The method of  claim 21 , further comprising contacting the biological sample with a detectably-labeled reporter agent that specifically binds to the detection reagent, and removing the unbound reporter agent. 
     
     
         24 . (canceled) 
     
     
         25 . The method of  claim 19 , wherein the electroactive molecule is a redox probe. 
     
     
         26 . The method of  claim 25 , wherein the redox probe is [Fe(CN) 6 ] 3−/4− . 
     
     
         27 . The method of  claim 14 , wherein the biofragment composition is immobilized indirectly to the surface by one or more intervening tether constructs. 
     
     
         28 - 33 . (canceled) 
     
     
         34 . The method of  claim 19 , wherein binding of the antigen of interest to the biofragment composition is detected by an increase in the electron transfer resistance as compared to the electron transfer resistance when the antigen of interest is not present. 
     
     
         35 - 40 . (canceled) 
     
     
         41 . The method of  claim 13 , wherein the cell is selected from the group consisting of a yeast, bacterium, plant, or animal cell. 
     
     
         42 . The method of  claim 41 , wherein the yeast is from the genus  Saccharomyces  or  Pichia.    
     
     
         43 . The method of  claim 13 , wherein the surface fragment is less than 200 nm at its greatest dimension. 
     
     
         44 . The method of  claim 13 , wherein the antigen-binding molecule is an antibody, an antigen-binding antibody fragment, or a T-cell receptor (TCR). 
     
     
         45 . The method of  claim 44 , wherein the antibody-like molecule is a single-chain antibody, a bispecific antibody, an Fab fragment, or an F(ab) 2  fragment. 
     
     
         46 . The method of  claim 45 , wherein the single-chain antibody is a single-chain variable fragment (scFv), single-chain Fab fragment (scFab), V H H fragment, V NAR , or nanobody.