High efficiency microfluidic purification of stem cells to improve transplants

Abstract

Described herein is a novel, highly efficient system to remove erythrocytes and purify leukocytes would raise the quality of UCB and other transplant grafts, thereby significantly improving patient outcomes.

1 - 12 . (canceled) 
     
     
         13 . A method for purifying leukocytes from a sample comprising leukocytes and smaller cells, wherein said smaller cells are erythrocytes and/or cells smaller than erythrocytes, the method comprising:
 (a) separating the leukocytes from the smaller cells by a size based separation on a microfluidic device, wherein said microfluidic device comprises posts with one or more non-rounded vertices, said posts being positioned in the microfluidic device such that when sample is flowed through the device, leukocytes travel in one direction and said smaller cells travel in a different direction, thereby achieving a separation;   (b) obtaining a product comprising leukocytes from said microfluidic device;   wherein:   i) the microfluidic device is operated at a linear flow rate of at least 5 mm/sec;   ii) relative to the sample, the product is enriched in leukocytes and depleted in said smaller cells;   iii) the product comprises less than 0.01 M/μl erythrocytes and/or less than 10% of the cells in the product are erythrocytes;   iv) greater than 90% of the leukocytes collected in the product are viable.   
     
     
         14 . The method of  claim 13 , wherein adjacent posts define a gap through which fluid flows and at least one vertex of a post points into the gap. 
     
     
         15 . The method of  claim 13 , wherein said posts have at least one vertex in which a ratio of the radius of curvature to characteristic dimension is not greater than 0.25. 
     
     
         16 . The method of  claim 13 , wherein said posts are triangular. 
     
     
         17 . The method of  claim 13 , wherein said posts are square, rectangular, trapezoidal or hexagonal. 
     
     
         18 . The method of  claim 13 , wherein said smaller cells comprise platelets. 
     
     
         19 . The method of  claim 13 , wherein said microfluidic device is operated at a flow rate of at least 100 ml/hr. 
     
     
         20 . The method of  claim 13 , wherein said microfluidic device is operated at a linear flow rate of 5 mm/sec to 150/mm/sec. 
     
     
         21 . The method of  claim 13 , wherein, relative to the sample, the product has a yield of leukocytes of greater than 90%. 
     
     
         22 . The method of  claim 13 , wherein the method does not use centrifugation or differential sedimentation. 
     
     
         23 . The method of  claim 13 , wherein the microfluidic device is operated at a flow rate of 100-300 ml/hr and erythrocytes in the sample are reduced by greater than 99% in the product compared to the sample. 
     
     
         24 . The method of  claim 13 , wherein said smaller cells are present in the sample at greater than a 1000-fold excess over the leukocytes. 
     
     
         25 . The method of  claim 13 , wherein at least 100 ml of said sample is applied to said microfluidic device. 
     
     
         26 . The method of  claim 25 , wherein adjacent posts define a gap through which fluid flows and at least one vertex of a post points into the gap. 
     
     
         27 . The method of  claim 25 , wherein said microfluidic device is operated at a flow rate of at least 100 ml/hr. 
     
     
         28 . The method of  claim 25 , wherein said microfluidic device is operated at a linear flow rate of 5 mm/sec to 150/mm/sec. 
     
     
         29 . The method of  claim 25 , wherein the method does not use centrifugation or differential sedimentation. 
     
     
         30 . The method of  claim 25 , wherein the microfluidic device is operated at a flow rate of 100-300 ml/hr and erythrocytes in the sample are reduced by greater than 99% in the product compared to the sample. 
     
     
         31 . The method of  claim 25 , wherein said smaller cells are present in the sample at a greater than a 1000-fold excess over the leukocytes. 
     
     
         32 . The method of  claim 25 , wherein 100-300 ml of said sample is applied to said microfluidic device.