Tagged ligands for enrichment of rare analytes from a mixed sample

Abstract

Method of enriching specific cells from cellular samples are disclosed, comprising contacting in solution a cellular sample with affinity-tagged ligands (ATLs) each comprising a first ligand linked to an affinity tag, wherein the ligand selectively binds a cellular marker of the rare cells and the affinity tag can be selectively captured by a capture moiety, wherein the affinity tags do not comprise a magnetic particle; and flowing the sample through a microfluidic device comprising the capture moiety to selectively retain ATL-bound cells. Methods for enriching circulating tumor cells, and devices for enriching specific cells from cellular samples are also disclosed.

What is claimed is: 
     
         1 . A method for enriching rare analytes from a sample comprising:
 contacting in solution said sample with a plurality of affinity-tagged ligands (ATLs) wherein said mixture of ATL's comprises:
 a first ATL comprising a first ligand that selectively binds a first marker of said rare analytes, wherein said first ligand is linked to a first affinity tag that is selectively captured by a first capture moiety; and 
 a second ATL comprising a second ligand that selectively binds a second marker of said rare analytes, wherein said second ligand is linked to a second affinity tag, wherein said second affinity tag is selectively captured by said first capture moiety; and 
   contacting said sample with said capture moiety to selectively enrich said rare analytes.   
     
     
         2 . The method of  claim 1 , wherein said first affinity tag and said second affinity tag are identical. 
     
     
         3 . The method of  claim 1 , wherein said mixture of ATL's comprises at least 3, 4, 5, 6, 7, 8, 9, or 10 ATL's each of which comprises an affinity tag that can be selectively captured by the first capture moiety. 
     
     
         4 . The method of  claim 1 , wherein said analytes are cells and said mixture is a blood sample. 
     
     
         5 . The method of  claim 1 , wherein each of said ATL's comprises a ratio of Ligand:Affinity Tag that is less than 1:5. 
     
     
         6 . The method of  claim 5 , wherein said capture moiety is in a microfluidic device. 
     
     
         7 . The method of  claim 6 , wherein said microfluidic device comprises an array of obstacles. 
     
     
         8 . The method of  claim 1 , wherein said affinity tag comprises biotin, desthiobiotin, histidine, polyhistidine, myc, hemagglutinin (HA), FLAG, fluorescence tag, tandem affinity purification (TAP) tags, FLAG, glutathione S transferase (GST) or derivatives thereof. 
     
     
         9 . The method of  claim 1 , wherein said ligand is linked to said affinity tag via a linker comprising one or more of modified dextran, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone. 
     
     
         10 . The method of  claim 1 , wherein the cellular marker is a cancer marker for one or more of breast, prostate, liver, ovary, skin, colon, rectum, cervix, esophagus, stomach, brain, lung, or endometrium cancer. 
     
     
         11 . The method of  claim 1 , wherein the ligand selectively binds epidermal growth factor receptor (EGFR) or folic acid receptor. 
     
     
         12 . The method of  claim 1 , wherein the capture moiety comprises avidin, streptavidin, Neutravidin™, nickel, or glutathione.