Microfabricated Cell Sorter

Abstract

The invention provides a microfabricated device for sorting cells based on a desired characteristic, for example, reporter-labeled cells can be sorted by the presence or level of reporter on the cells. The device includes a chip having a substrate into which is microfabricated at least one analysis unit. Each analysis unit includes a main channel, having a sample inlet channel, typically at one end, and a detection region along a portion of its length. Adjacent and downstream from the detection region, the main channel has a discrimination region or branch point leading to at least two branch channels. The analysis unit may further include additional inlet channels, detection points, branch points, and branch channels as desired. A stream containing cells is passed through the detection region, such that on average one cell occupies the detection region at a given time. The cells can be sorted into an appropriate branch channel based on the presence or amount of a detectable signal such as an optical signal, with or without stimulation, such as exposure to light in order to promote fluorescence.

1 . A device for sorting biological material comprising:
 a microfabricated substrate having at least one main channel and at least two branch channels which meet at a junction,   a detection region upstream and proximate to the junction comprising a detection apparatus for evaluating the biological material according to at least one characteristic as the material passes through the detection region,   a discrimination region downstream from the detection region,   a flow control system responsive to the detection apparatus and adapted to direct biological material through the discrimination region into a branch channel.   
     
     
         2 . A device of  claim 1 , wherein at least one of the main and outlet channels communicates with a reservoir. 
     
     
         3 . A device of  claim 1 , wherein the substrate is comprised of silicon. 
     
     
         4 . A device of  claim 1 , wherein the substrate comprises a silicone elastomer. 
     
     
         5 . A device of  claim 1  wherein the biological material comprises cells. 
     
     
         6 . A device of  claim 4  wherein the silicone elastomer substrate is made from an impression of an etched silicon wafer. 
     
     
         7 . A device of  claim 1  wherein the flow control system is electro-osmotic. 
     
     
         8 . A device of  claim 1  wherein the flow control system is electrophoretic. 
     
     
         9 . A device of  claim 1  wherein the flow control system is dielectrophoretic. 
     
     
         10 . A device of  claim 1  wherein the flow control system is pressure driven. 
     
     
         11 - 37 . (canceled) 
     
     
         38 . A method for sorting a fluid mixture of cells comprising:
 providing the mixture of cells to a main channel of a microfabricated substrate, wherein the main channel is in fluid communication with at least two downstream branch channels which meet at a junction;   producing a flow of fluid in the channels;   interrogating each cell for a predetermined characteristic as it passes a detection region associated with the main channel;   generating a signal indicating the results of the interrogation;   directing the flow of each cell into a selected branch channel according to the signal.   
     
     
         39 . (canceled) 
     
     
         40 . A method of  claim 38  wherein the characteristic is an optically detectable reporter in or on the cells. 
     
     
         41 . A method of  claim 38  wherein the cells are interrogated by at least one device selected from the group of microscopes, diodes, light stimulating devices, lasers, light scattering apparatuses, electromagnetic excitation sources, electromagnetic radiation detector apparatuses, photomultiplier tubes, and processors. 
     
     
         42 . A method of  claim 38  wherein the reporter is selected from a dye, fluorescent agent, chemiluminescent agent, chromophore, radio-isotope, and optically detectable protein. 
     
     
         43 . A method of  claim 38  wherein the flow is controlled by electro-osmosis, electrophoresis, dielectrophoresis, pressure gradient, microvalve, optical trapping and flow stoppage. 
     
     
         44 . A method of  claim 43  wherein the flow control is provided by a voltage gradient between the branch channels and the junction. 
     
     
         45 . A method of  claim 44  wherein the voltage gradient is generated by electrodes in the branch channels. 
     
     
         46 . A method of  claim 44  wherein the main channel comprises an electrode. 
     
     
         47 . A method of  claim 43  wherein the flow control is by a pressure gradient between one or more channels and the junction. 
     
     
         48 . A method of  claim 43  wherein the pressure gradient is provided by capillary action at one or more channels of the substrate. 
     
     
         49 - 50 . (canceled)