Silicone surfactants for emulsion assays

Abstract

System, including methods and compositions, for making and using emulsions that include a silicone oil and a silicone surfactant. The emulsions may include aqueous droplets disposed in a continuous phase that includes a silicone oil and a silicone surfactant. The aqueous droplets may contain an analyte, optionally at partial occupancy, and/or a luminescent (e.g., photoluminescent) reporter. An assay of the analyte may be performed with the droplets. In some cases, signals may be detected from the droplets, and a characteristic of the analyte, such as an analyte level or activity, may be determined based on the signals.

We claim: 
     
         1 . A composition comprising at least one silicone surfactant having the formula: 
       
         
           
           
               
               
           
         
       
       the formula 
       
         
           
           
               
               
           
         
       
       or the forumula 
       
         
           
           
               
               
           
         
       
       wherein
 each g is independently 5-200; 
 each h is independently 1-5; 
 each i is independently 1-5; 
 each j is independently 15-50; and 
 each k is independently 2-100. 
 
     
     
         2 . The composition of  claim 1 , wherein the composition is an emulsion of aqueous droplets in a silicone oil phase. 
     
     
         3 . The composition of  claim 2 , wherein the silicone oil phase includes one or more of octamethyl trisiloxane and a polydimethylsiloxane polymer. 
     
     
         4 . The composition of  claim 2 , wherein the at least one silicone surfactant is present in the composition at a concentration of 0.1% to 10% in the silicone oil phase. 
     
     
         5 . The composition of  claim 2 , wherein the aqueous droplets include a photoluminescent reporter. 
     
     
         6 . The composition of  claim 2 , wherein the aqueous droplets include an analyte that is a nucleic acid. 
     
     
         7 . The composition of  claim 2 , wherein the silicone oil phase includes octamethyl trisiloxane, cyclopentasiloxane or a trimethylsiloxysilicate at a concentration of about 0.1% to 5%. 
     
     
         8 . The composition of  claim 7 , wherein the at least one silicone surfactant is present at a concentration of about 0.2% to 5% by weight in the silicone oil phase.