Patent Publication Number: US-2016228869-A1

Title: Device, system, and method for selecting a target analyte or fluid

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     This application is a continuation of application Ser. No. 14/643,891, filed Mar. 10, 2015, which is a continuation-in-part of application Ser. No. 14/248,510, filed Apr. 9, 2014, which claims the benefit of Provisional Application No. 61/810,834, filed Apr. 11, 2013, and Provisional Application No. 61/922,931, filed Jan. 2, 2014. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to micromanipulation of a target analyte, though more specifically, to picking and isolating the target analyte. 
     BACKGROUND 
     Suspensions often include materials of interest that are difficult to detect, extract and isolate for analysis. For instance, whole blood is a suspension of materials in a fluid. The materials include billions of red and white blood cells and platelets in a proteinaceous fluid called plasma. Whole blood is routinely examined for the presence of abnormal organisms or cells, such as fetal cells, endothelial cells, epithelial cells, parasites, bacteria, and inflammatory cells, and viruses, including HIV, cytomegalovirus, hepatitis C virus, and Epstein-Barr virus, and nucleic acids. Currently, practitioners, researchers, and those working with blood samples try to separate, isolate, and extract certain components of a peripheral blood sample for examination. Typical techniques used to analyze a blood sample include the steps of smearing a film of blood on a slide and staining the film in a way that enables certain components to be examined by bright field microscopy. 
     On the other hand, materials of interest composed of particles that occur in very low numbers are especially difficult if not impossible to detect and analyze using many existing techniques. Consider, for instance, circulating tumor cells (“CTCs”), which are cancer cells that have detached from a tumor, circulate in the bloodstream, and may be regarded as seeds for subsequent growth of additional tumors (i.e., metastasis) in different tissues. The ability to accurately detect and analyze CTCs is of particular interest to oncologists and cancer researchers, but CTCs occur in very low numbers in peripheral whole blood samples. For instance, a 7.5 ml sample of peripheral whole blood that contains as few as 3 CTCs is considered clinically relevant in the diagnosis and treatment of a cancer patient. However, detecting even 1 CTC in a 7.5 ml blood sample may be clinically relevant and is equivalent to detecting 1 CTC in a background of about 50 billion red and white blood cells. Using existing techniques to find, isolate and extract as few as 3 CTCs of a whole blood sample is extremely time consuming, costly and is extremely difficult to accomplish. 
     As a result, practitioners, researchers, and those working with suspensions continue to seek systems and methods to more efficiently and accurately detect, isolate and extract target materials of a suspension. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1D  show examples of a picker. 
         FIG. 2A-2D  show an example picker. 
         FIG. 3A  shows an example picker. 
         FIG. 3B  shows an example picker. 
         FIGS. 4A-4C  show an example picker. 
         FIG. 5  shows an example cannula with a fluorescent tip. 
         FIGS. 6A-6B  show an example fluorescent picker tip. 
         FIGS. 7A-7E  show example picker tips. 
         FIGS. 8A-8B  show an example picking system. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure is directed to a device and a system for aspirating and dispensing a target analyte, target material, or fluid. A picker may aspirate and dispense the desired material by introducing a pressure gradient. The picker may include a hydraulic fluid to hydraulically couple at least two components, such as a moveable pump component and a cannula. 
     Picker and Picking System 
       FIG. 1A  shows an example picker  100 . The picker  100  includes a main body  102 , a back end  104 , and a tip  106 . The picker  100  may be solid or may be a hollow tube having an inner chamber for holding a liquid, target analyte, or any other appropriate material. When the picker  100  is a hollow tube, the picker  100  may also include a liquid  108  within the inner chamber of the picker  100 , where the liquid may be a solution, a buffer, a ferrofluid, or the like. The picker  100  may be used to manipulate a target analyte. The target analyte may be manipulated, such as by moving, removal, or isolation, when the specific target analyte is in a vessel, such as a tube or a well, or on a slide. The target analyte can be isolated through the introduction of a force, thereby attracting or pulling the target analyte. The tip  106  engages the target analyte for moving, removal, or isolation. The force may be created with suction or a pressure gradient, such as a vacuum. The back end  104  may be connected to a pump  110 , such as a vacuum pump, a lead screw, or a hand pump with a wheel, to aid in providing the force for moving, removal, or isolation. The picker  100  may also include a light source  112 , such as an LED, to illuminate an area in which the target analyte may be present. The light source  112  may be located anywhere along the main body  102 , including the back end  104  and the tip  106 . When the light source  112  is located at the back end  104 , the main body  102  may be composed of a material capable of propagating or transmitting a light signal produced by the light source  112 , such that the light signal exits at the tip  106  to illuminate the desired area. The light source  112  may be connected to a power supply (not shown), such as a battery, to supply current or power. 
       FIG. 1B  shows an example picker  114 . The picker  114  is similar to the picker  100 , except that picker  114  includes a permanent magnet  116 , such as a donut-shaped magnet. The permanent magnet  116  generates a magnetic field for attracting a particle of a target analyte-particle complex, a target analyte having been previously conjugated with the particle to form the target analyte-particle complex. The picker  114  may also include a magnetizable material to extend or transmit the magnetic field produced by the magnet. The permanent magnet  116  may be located at the tip  106  or at or near the back end  104 . The permanent magnet  116  may be removable. Alternatively, the fluid, such as a ferrofluid, within the picker  114  may be used to generate the magnetic field or magnetic gradient. 
       FIG. 1C  shows an example picker  120 . The picker  120  is similar to the picker  100 , except that picker  120  includes an electromagnet. The electromagnet includes a power source  122 , a first lead  126 , a second lead  128 , and a coil  124 . The power source  122  may be, but is not limited to, a battery, a DC supply, or an AC supply. The electromagnet generates a magnetic field for attracting a particle of a target analyte-particle complex, a target analyte having been previously conjugated with the particle to form the target analyte-particle complex. The picker  120  may be composed of a magnetizable material to extend or transmit the magnetic field produced by the magnet. The first lead  126 , the second  128 , and the coil  124  may be located outside of a wall of the picker  120 , may be embedded with the wall of the picker  120 , or may be located inside of the picker  120 . The picker  120  may also include a light source  130 , such as an LED, to illuminate an area in which the target analyte may be present. The light source  130  may be located anywhere along the main body  102 , including the back end  104  and the tip  106 . When the light source  130  is located at the back end  104 , the main body  102  may be composed of a material capable of propagating or transmitting a light signal produced by the light source  130 , such that the light signal exits at the tip  106  to illuminate the desired area. The light source  130  may be connected to a power supply (not shown), such as a battery, to supply current or power. 
       FIG. 1D  shows an example picker  140 . The picker  140  includes a retractable shaft  142 , the retractable shaft  142  being thinner than the main body  102  and being extendable from the tip  106 . The retractable shaft  142  can be located within the main body  102 , can be extended out of the tip  106  to engage a target analyte, and can be retracted into the main body  102 . When the target analyte attaches to the retractable shaft  142 , the target analyte can be drawn into the main body  102 . The retractable shaft  142  may include an engagement portion  152 , a stopper  144 , a grip  150 , and a rod  148 . The engagement portion  152  may be extended out of the tip  106  to engage the target analyte. The stopper  144  may be sized to fit within the main body  102 , but be larger than the tip  106  or a taper from the main body  102  to the tip  106 , thereby preventing the retractable shaft  142  from extending too far from the tip  106 . The grip  150  may allow for engagement of the retractable shaft  142 , so as to properly move the retractable shaft  142 . The rod  148  may connect the stopper  144  or the engagement portion  146  to the grip  140 . The retractable shaft  142  may also be made magnetizable by including a magnet  146  disposed on or within the retractable shaft  142 . The magnetic field or magnetic gradient may be removed or deactivated, such as by removing the magnet  146  or turning off an electromagnet. The target analyte-particle complex is no longer attracted and held to the retractable shaft  142  causing the target analyte-particle complex to remain within the liquid in the main body  102 . The picker  140  may also include a light source  130 , such as an LED, to illuminate an area in which the target analyte may be present. The light source  130  may be located anywhere along the main body  102 , including the back end  104  and the tip  106 . When the light source  130  is located at the back end  104 , the main body  102  may be composed of a material capable of propagating or transmitting a light signal produced by the light source  130 , such that the light signal exits at the tip  106  to illuminate the desired area. The light source  130  may be connected to a power supply (not shown), such as a battery, to supply current or power. 
     Alternatively, the retractable shaft  142  may be magnetized by an electromagnet, such as a coil wrapped around a segment of or the entire retractable shaft  142 . Alternatively, the picker  140  may include a pump (not shown), such as a vacuum pump, a lead screw, or a hand pump with a wheel, to aid in providing the force for moving, removal, or isolation. 
       FIG. 2A  shows an example picker  200 .  FIG. 2B  shows a cross-sectional view of the example picker  200  taken along the line I-I. The picker  200  includes a piston  202 , a pump block  204 , and a cannula  208 . The picker  200  may also include a fitting  206  with a first side  218  and a second side  220 . The piston  202  includes a first end  210  and a second end  212 . The cannula  208  includes an adapter  214  and a tube end  216 , the tube end  216  including a picker tip  224 . The first side  218  of the fitting  206  mates with the pump block  204 , such as by a press-fit, detents, notches, complementary threads, or the like. A seal  222  may be formed between the first side  218  of the fitting  206  or the adapter  214  of the cannula  208  and the pump block  204 , such as by an O-ring, grease, silicone grease, or the like, to close the picker  200 . The adapter  214  of the cannula  208  may mate with the second side  220  of the fitting  206  or the pump block  204 , such as by a press-fit, detents, notches, complementary threads, or the like. In other words, the cannula  208 , without the inclusion of the fitting  206 , may be connected directly to the pump block  204 . 
     The piston  202  may be any appropriate length. The second end  212  of the piston  202  may be located within the pump block  204 , within the fitting  206 , within the adapter  214  of the cannula  208 , or within the tube end  216  of the cannula  208 . The second end  212  of the piston  210  may extend through the seal  222 . The first end  210  of the piston  202  may be located within the pump block  204  or may extend out of a side of the pump block  204  opposite the side of the pump block  204  that is connected, whether directly or indirectly, to the cannula  208 . The piston  202  and the cannula  208  may substantially share a central axis. The positioning of the piston  202  relative to the cannula  208  reduces or eliminates dead volume. 
     The pump block  204  at least partially houses the piston  202  and allows for translation of the piston  202  relative to the pump block  204 . Moving the piston  202 , such as a lead screw or rod, upwards within the pump block  204  may create a negative pressure at the tube end  216  so as to draw a target analyte or fluid from the suspension into the cannula  208  or may create a positive pressure to expel a target analyte or fluid located within the cannula  208  from the tube end  216 . The piston  202  may be connected to a motor or an actuator to drive the piston  202  up and down, thereby creating the desired pressure differential. The pump block  204  may include a complementary mating feature, such as threads or a bore, to accept and mate with the piston  202 . When the piston  202  and the pump block  204  include complementary threads, the piston  202  may be rotated to cause the desired translation. A full rotation of the piston  202  may include any number of steps, including 1-10,000 steps. Those steps may then include any number of micro-steps, including 1-10,000 micro-steps. Each step or micro-step may draw in a volume approximately equal to or less than 1 picoliter, 10 picoliters, 100 picoliters, 1 nanoliter, 1 microliter, or 1 milliliter. A piezo-electric pump (not shown) may also be placed in series with the piston  202 , such as on the second  212  of the piston  202 , thereby allowing for even smaller volumes to be processed. The piezo-electric pump (not shown) may be connected to a voltage source (not shown) to cause the deformation required to generate the desired negative or positive pressure. 
     The piston  202  and the cannula  208  may be hydraulically coupled, such that the volume from the tube end  216  of the cannula  208  to the seal  222  is filled with a hydraulic fluid  226 . The volume from the tube end  216  of the cannula  208  to the seal  222  filled with the hydraulic fluid  226 , which may also be referred to as a pump volume, may be contained in a rigid structure, rather than a flexible structure, to maintain the hydraulic coupling efficiency. The hydraulic fluid  226  may be incompressible or have low compressibility. The hydraulic fluid  226  may be a solution, an oil, a liquid metal, a buffer, water, or the like. Hydraulically coupling the piston  202  and the cannula  208  provides better small volume control (i.e. full piston travel draws/expels 1-50 μL) than a non-hydraulically coupled picker (i.e. filled with air). The hydraulic fluid  226  may include a fluid plug, such that two volumes of the hydraulic fluid  226  are separated by a volume of air or a different liquid. The pump volume, which is constant, satisfies the condition given by: 
         V   P   =V   HF   +V   MPC   +V   PM   +V   Air , 
     where V P  represents the pump volume, V HF  represents the volume of the hydraulic fluid, V MPC  represents the volume of the portion of the at least one movable pump component within the pump volume, where V PM  represents the volume of any picked or aspirated material, and where V Air  represents the volume of air within the pump volume. In this instance, the at least one moveable pump component is the piston  202 . Because the pump volume is constant and the piston  202  may be substantially cylindrical, the volume of the piston  202  satisfies the conditions given by: 
     
       
      
       V 
       MPC 
       =πr 
       2 
       h,  
      
     
     where V MPC  represents the at least one moveable pump component (i.e. the piston  202 ), r represents the radius of the second end  212  of the piston  202 , h represents the amount of the piston  202  within the pump volume. Alternatively, the piston  202  may be substantially square, rectangular, triangular, pentagonal, or any other appropriate polygonal shape. Accordingly, the volume of the piston  202  would satisfy the equations for the volumes of the respective shapes. 
       FIG. 2C  shows the picker  200  with the piston  202  having been driven towards the picker tip  224 . The distance (d) traveled by the piston  202  may be used to calculate the new volume of the piston  202  within the pump volume based on the shape of the piston  202 . The distance (d) may be positive (piston  202  moves towards picker tip  224 ; and, accordingly, creates a positive pressure gradient) or negative (piston  202  moves away from picker tip  224 ; and, accordingly, creates a negative pressure gradient). The new volume of the piston  202  therefore satisfies the conditions given by: 
         V   MPC   =πr   2 ( h+d ), 
     where V MPC  represents the at least one moveable pump component (i.e. the piston  202 ), r represents the radius of the second end  212  of the piston  202 , h represents the amount of the piston  202  within the pump volume, and d represents the distance traveled by the piston  202  within the pump volume. With respect to the pump volume equation discussed above (V P =V HF +V MPC +V PM +V Air ), the pump volume remains constant because the difference between the first and second volumes occupied by the at least one moveable component (i.e. piston  202 ) is equal to the amount of the hydraulic fluid  226 , picked or aspirated material, and/or air displaced from the pump volume. 
       FIG. 2D  shows the picker  200  with the piston  202  having been driven away the picker tip  224  and drawing in a target material  230  and air  232 . Though  FIGS. 2B-2D  depict the piston  202  being driven towards and then away from the picker tip  224  to draw in the target material  230 , and consequently some air  232 , the piston  202  may be driven in any appropriate manner and in appropriate amount to create the desired pressure gradient. It should be further noted that the air  232  may not be drawn in when drawing in the target material  230 . The target material  230  may include, but is not limited to, biological matter (i.e. cells, tissue, biological fluid, etc.) or other fluids (i.e. phosphate buffered saline, enzymatic fluids, adherent solutions, water, etc.). 
     The picker  200  may introduce a magnetic gradient as well, such as by a permanent magnet or an electromagnet, as shown in  FIGS. 1B and 1C , respectively, whereby the cannula  208 , the hydraulic fluid  226 , or the tube end  216  is magnetizable so as to propagate the magnetic gradient. The permanent magnet may be located along the tube end of the cannula, on the piston, or anywhere on the picker tip. When a ferrofluid primes the cannula, the permanent magnet may be located near the adapter. The electromagnet includes a coil, a first lead, a second lead, and a power supply, such as a battery. The coil wraps around the tube end of the cannula or the picker tip. A first end of the first lead is connected to the power supply and a second end of the first lead is connected to a first end of the coil. A first end of the second lead is connected to the power supply and a second end of the second lead is connected to a second end of the coil. The power supply is disposed outside of the pump block. 
       FIG. 3A  shows a picker  300 . The picker  300  is similar to the picker  200  except that the picker  300  includes a light source  302 . The light source  302  produces a light signal that is propagated or transmitted by the cannula  208  or picker tip inserted into, over, or in-line with the cannula  208 . The cannula  208  or the picker tip may be composed of a material capable of propagating or transmitting the light signal produced by the light source  302 , such that the light signal exits at the tube end  216  of the cannula  208  or the end of the picker tip furthest away from the pump block  204  to illuminate the desired area and/or stimulate a fluorescent probe bound to a target analyte. When the light source  302 , such as an LED, originates at a location other than the tube end  216  of the cannula  208  or the end of the picker tip furthest away from the pump block  204 , a cable  304 , such as a fiber optic cable, may transmit the light signal to the tube end  216  of the cannula  208  or the end of the picker tip furthest away from the pump block  204  for illumination and/or stimulation purposes. The light source  302  may provide epi-, transmitted, or oblique illumination. The light source  302  may be connected to a power supply (not shown), such as a battery, to supply current or power. Alternatively, the light source  302  may be between the top of the adapter of the cannula  208  and the fitting  206 . Alternatively, at least one light source  302  may be embedded in the tube end of the cannula  208 . Alternatively, the light source  302  may be located on the adapter  214  or the pump block  204 . 
       FIG. 3B  shows a picker  310 . The picker  310  is similar to the picker  200  except that the picker  310  includes a port  312 . The port  244  may extend through the second end of the pump block  204  and either the first end  218  of the fitting  206  or the adapter  214  of the cannula  208 . The port  312  may be connected to a loader  314 , such as a piezoelectric pump, to fill the pump volume. The loader  314  may be connected to a reservoir  316  with a tube  318 . The tube  318  may be rigid or flexible. Alternatively, the loader  314  may be interchanged with a pressure sensor (not shown) to measure the pressure within the pump volume to make sure the picker  310  does not clog. 
       FIG. 4A  shows a picker  400 .  FIGS. 4B and 4C  show cross-section views of the picker  400  taken along the line II-II. The picker  400  includes a pump block  402  with a diaphragm  404 . The picker  400  also includes the cannula  208 , as discussed above, and the seal  222 , as discussed above. Further, the seal  222  may be formed between the adapter  214  of the cannula  208  or the fitting (not shown) and the pump block  402 , such as by an O-ring or silicone grease, to close the picker  400 . The adapter  214  of the cannula  208  may mate with the fitting (not shown) or the pump block  402 , such as by a press-fit, detents, notches, complementary threads, or the like. In other words, the cannula  208 , without the inclusion of the fitting (not shown), may be connected directly to the pump block  402 . 
     The at least one movable pump component is the diaphragm  404  which deforms into the pump block  402  to occupy a portion of the pump volume in response to a stimulus. The stimulus may include, but is not limited to, electrical energy, thermal energy, acoustic energy, applied pressure, or electromagnetic energy. The diaphragm  404  may be composed of crystal, ceramic, polymers, plastics, metal, glass, or combinations thereof. 
     The diaphragm  404  and the cannula  208  may be hydraulically coupled, such that the volume from the tube end  216  of the cannula  208  and into the pump block  402  is filled with a hydraulic fluid  226 . The volume from the tube end  216  of the cannula  208  and into the pump block  402  filled with the hydraulic fluid  226 , which may also be referred to as a pump volume, may be contained in a substantially rigid structure, with the exception of the diaphragm  404 , rather than a flexible structure, to maintain the hydraulic coupling efficiency. The hydraulic fluid  226  may be incompressible or have low compressibility. The hydraulic fluid  226  may be a solution, an oil, a liquid metal, a buffer, water, or the like. Hydraulically coupling the diaphragm  404  and the cannula  208  provides better small volume control (i.e. full piston travel draws/expels 1-50 μL) than a non-hydraulically coupled picker (i.e. filled with air). The hydraulic fluid  226  may include a fluid plug, such that two volumes of the hydraulic fluid  226  are separated by a volume of air or a different liquid. The pump volume, as seen in  FIG. 4B , which is constant, satisfies the condition given by: 
         V   P   =V   HF   +V   MPC   +V   PM   +V   Air , 
     where V P  represents the pump volume, V HF  represents the volume of the hydraulic fluid, V MPC  represents the volume of the portion of the at least one movable pump component within the pump volume, where V PM  represents the volume of any picked or aspirated material, and where V Air  represents the volume of air within the pump volume. In this instance, the at least one moveable pump component is the diaphragm  404 . 
       FIG. 4C  shows the picker  400  with the diaphragm  404  having been driven into the pump block  402 . The initial deformation distance (d i ) of the diaphragm  404  within the pump block  402  may be used to calculate the new volume occupied by the diaphragm  404  within the pump volume based on the shape of the diaphragm  404 . The change in deformation (Δd) from the initial deformation distance to a second deformation distance (d s ; where Δd=d s −d i ) may be positive (diaphragm  404  deforms into the pump block  402 ; and, accordingly, creates a positive pressure gradient) or negative (diaphragm  404  withdraws from the pump block  402 ; and, accordingly, creates a negative pressure gradient). When the pump volume is constant, the diaphragm  404  does not deform away from the pump block  402 . Therefore, the furthest that the diaphragm  404  withdraws from the pump block  402  is when the diaphragm  404  sits flush with the walls of the pump block  402 , as seen in  FIG. 4B . It should be further noted that the dashed line in  FIG. 4C  denotes the neutral state of the diaphragm  404  to highlight the constant pump volume. The volume occupied by the diaphragm  404  within the pump block  402  due to the deformation of the diaphragm  404 , therefore satisfies the conditions given by: 
     
       
         
           
             
               
                 V 
                 MPC 
               
               = 
               
                 
                   1 
                   6 
                 
                  
                 
                   π 
                    
                   
                     ( 
                     
                       
                         d 
                         i 
                       
                       + 
                       
                         Δ 
                          
                         
                             
                         
                          
                         d 
                       
                     
                     ) 
                   
                 
                  
                 
                   ( 
                   
                     
                       3 
                        
                       
                         
                           ( 
                           
                             l 
                             2 
                           
                           ) 
                         
                         2 
                       
                     
                     + 
                     
                       3 
                        
                       
                         
                           ( 
                           
                             
                               d 
                               i 
                             
                             + 
                             
                               Δ 
                                
                               
                                   
                               
                                
                               d 
                             
                           
                           ) 
                         
                         2 
                       
                     
                   
                   ) 
                 
               
             
             , 
           
         
       
     
     where V MPC  represents the at least one moveable pump component (i.e. the diaphragm  404 ), l represents the length of the diaphragm  404  in the picker  400  in the neutral state (as shown in  FIG. 4B  and represented by the dashed line in  FIG. 4C ), d i  represents the initial deformation distance of the diaphragm  404  within the pump volume, and Δd represents the change in deformation of the diaphragm  404  within the pump volume. With respect to the pump volume equation discussed above (V P =V HF +V MPC +V PM +V Air ), the pump volume remains constant because the different between the first and second volumes occupied by the at least one moveable component (i.e. diaphragm  404 ) is equal to the amount of the hydraulic fluid  226 , picked or aspirated material, and/or air displaced from the pump volume. For example, in  FIG. 4B , d i  would be 0, because the diaphragm  404  sits flush with the walls of the pump block  402 . However, when the diaphragm  404  deforms, as shown in  FIG. 4C , the change in deformation is Δd. Now, when the diaphragm  404  deforms again (i.e. from  FIG. 4C  to another deformation), d i  is the initial distance of deformation as shown in  FIG. 4C  and Δd is any change in deformation to the new distance of deformation. 
     Alternatively, when a variable pump volume is desirable, the diaphragm  404  may deform away from the pump block  402 . When the diaphragm  404  is able to deform away from the pump block  402 , the pump volume may be variable based on the deformation of the diaphragm. 
       FIG. 5  shows a cannula  500 . The cannula  500  is similar to the cannula  208 , except that a tube end  502  of the cannula  500  includes a fluorescent tip  504 . The fluorescent tip  504  emits light in a particular wavelength when excited or stimulated by a stimulus, such as light with a first wavelength. The fluorescent tip  504  may be used to emit light that improves visualization of the cannula  500  for better placement over the desired target analyte during collection. Alternatively, the entire tube end  502  of the cannula  500  may be composed of a fluorescent material. 
       FIG. 6A  shows a picker tip  600 .  FIG. 6B  shows a cross-sectional view of the picker tip  600  taken along the line II-II. The picker tip  600  may be two pieces, such that the picker tip  600  may be inserted into, over, or in-line with the tube end  216  of the cannula  208 . Alternatively, the picker tip  600  and the cannula  208  may be one piece. The picker tip  600  includes a main body  602  and a permeable membrane  610 . The main body  602  includes a first end  604  with a first bore  612  having a first diameter and a second end  606  with a tapered bore  614  having a second diameter which tapers to the same diameter as the first diameter of the first bore  612 . The second end  606  may be entirely fluorescent or a portion thereof may be fluorescent, or the second end  606  may not be fluorescent. The second diameter may be larger or smaller than the first diameter. Furthermore, the widest part of the tapered bore  614  may be less than or equal to 1 micrometer or less than or equal to 1 millimeter. 
     The first end  604  is inserted within the tube end  216  of the cannula  208 . The permeable membrane  610  may be located within the first bore  612  or the second bore  614  and is composed of a material including at least one pore. The permeable membrane  610  permits the target analyte to be drawn a distance into the picker. The picker tip  600  may also include a ridge  608  extending circumferentially from the main body  602  to prevent the picker tip  600  from translating further into the tube end  216  of the cannula  208 . 
       FIG. 7A  shows a picker tip  700 . The picker tip  700  may be inserted into, over, or in-line with the tube end  216  of the cannula  208 . Alternatively, the picker tip  700  may be formed, molded, machined or the like as a single piece with the tube end  216 . The picker tip  700  includes a first end  702 , a second end  704 , and a central bore  706 . The first end  702  is the portion of the picker tip  700  which be inserted into, placed over, or placed in-line with the tube end  216  of the cannula  208 . The picker tip  700  may be straight, tapered, or a combination thereof. The central bore  706  extends from the first end  702  to the second end  704  and may be straight, tapered, or a combination thereof. Furthermore, the portion of the central bore  706  at the second end  704  may be less than or equal to 1 micrometer or less than or equal to 1 millimeter. 
     Magnified view  708  shows the second end  704  with an outer segment removed to reveal the inner configuration of the second end  704 . The second end  704  may be flat or angled. The second end  704  may also include a counter-sink, as shown in  FIG. 7A . 
       FIG. 7B  shows a picker tip  710 . The picker tip  710  is similar to the picker tip  700  except that the picker tip  710  includes a sharpened second end  712 . Magnified view  716  shows the sharpened second end  712  having an outer wall  714  has an angle (θ) from the horizontal that may range from approximately 30° to approximately 89°. The sharpened second end  712  permits for better cutting of the desired target analyte from the substrate. The angle (θ) of the outer wall  714  permits selection of the desired target analyte without destroying any other analytes, whether target or non-target. The central bore  706  at the second end  712  may have a diameter that is less than or equal to approximately 100 micrometers. 
       FIG. 7C  shows a picker tip  720 . The picker tip  720  is similar to the picker tip  710  except that the picker tip  720  includes a flat extension  722  extending from the sharpened second end  712 , as seen in magnified view  724 . 
       FIG. 7D  shows a picker tip  730 . The picker tip  730  is similar to the picker tip  710  except that the picker tip  730  includes a flat second end  732 , as seen in magnified view  734 . 
       FIG. 7E  shows a picker tip  740 . The picker tip  740  may be inserted into, over, or in-line with the tube end  216  of the cannula  208 . Alternatively, the picker tip  740  may be formed, molded, machined or the like as a single piece with the tube end  216 . The picker tip  740  includes a first end  742 , a second end  744 , and a central bore  746 . The first end  742  is the portion of the picker tip  740  which be inserted into, placed over, or placed in-line with the tube end  216  of the cannula  208 . The picker tip  740  may be straight, tapered, or a combination thereof. The central bore  746  extends from the first end  742  to the second end  744  and may be straight, tapered, or a combination thereof. 
     Magnified view  748  shows the second end  744  with an outer segment removed to reveal the inner configuration of the second end  744 . The second end  744  includes an opening  750  to access the central bore  746 . An inner portion of the second end  744  includes a straight wall  752  extending from the opening  750  into the central bore. A curved wall  754  extends from the straight wall  752  further into the central bore  746 . An angled wall  758  extends from the curved wall  754  further into the central bore  746 . An upper wall  760  extends from the angled wall further into the central bore  746 . In other words, the central bore  746  has a first diameter that is substantially equal to the diameter of the opening  750 , which then increases in diameter along the curved wall  754  and the angled wall  758  until reaching the upper wall  760 , whereby the diameter may remain constant or increase along a taper. The diameter of the opening  750  and the straight wall  752  may be less than or equal to 1 micrometer or less than or equal to 1 millimeter. The radius of the curved wall  754  may be approximately 25 micrometers to 2.6 millimeters. The diameter of the central bore  746  where the angled wall  758  connects to the upper wall  760  may be approximately 125 micrometers to approximately 2.6 millimeters. 
     The second end  744  may be sharpened, thereby having an outer wall  756  that has an angle (θ) from the horizontal that may range from approximately 30° to approximately 89°. The sharpened second end  744  permits for better cutting of the desired target analyte from the substrate. The angle (θ) of the outer wall  756  permits selection of the desired target analyte without destroying any other analytes, whether target or non-target. 
       FIG. 8A  shows picking system  800  including a drive assembly  802 , the picker  200  as shown in  FIGS. 2A-2B , and an actuator  814 .  FIG. 8B  shows a cross-sectional view of the picking system  800 . Though picker  200  is described in relation to the picking system  800 , the picker  230  and the picker  240  may also be used. The drive assembly  802  includes a driver  804  including a first end and second end, a coupling  624  including a first end and a second end, and a housing  806 . The first end of the coupling  624  mates with the second end of the driver  804 , and the second end of the coupling  624  mates with the piston  202 . When the second end of the driver  804  rotates, the coupling  624  rotates, thereby causing the piston  202  to rotate and translate within the pump block  204 , the fitting  206 , and the cannula  208 . The driver  804 , the housing  806 , and the coupling  624  translate with the piston  202  along the same axis, such as the z-axis, relative to the pump block  204  which remains stationary. Translation of the driver  804 , the housing  806 , and the coupling  624  translate with the piston  202  along the same axis reduces backlash, such as by permitting use of a single-piece coupling, to allow for better system control. The driver  804 , the housing  806 , the coupling  624 , and the piston  202  may translate the same distance along the same axis. Alternatively, the second end of the driver  804  translates along a central axis, the coupling  624  translates along the central axis, thereby causing the piston  202  to translate within the pump block  204 , the fitting  206 , and the cannula  208 . 
     The driver  804  may be an electric motor (such as a servomotor, a stepper motor, a piezo-electric actuator, a solenoid, or the like), a manual motor (such as a knob), or the like. The driver  804  provides high resolution control of the picker  200 . The coupling  624  provides zero backlash and may be axially stiff and torsionally stiff. For example, the coupling  624  may be a single piece flexure coupling, a non-expanding bellows, split-beam drive assembly, or the like. 
     Furthermore, backlash may be reduced by restraining or eliminating movement of the driver  804  in 5 of 6 degrees of freedom. For example, the driver  804  may translate in the z-direction, but does not translate in the x- or y-directions nor does the driver  804  rotate around the x-, y-, or z-axes. Additionally, reduced or eliminated backlash permits for greater clearance between at least the pump block  204  and the housing  806 , which thereby reduces the friction between the at least two components, as well as better self-alignment of the piston  202  within the picking system  800 . 
     The housing  806  encases and protects at least the second end of the driver  804 , the coupling  624 , the first end  210  of the piston  202 , and at least a portion of the pump block  204 . The housing  806  may inhibit rotation of the driver  804  relative to the pump block  204 . The housing  806  also supports the driver  804 . The housing  806  may be fixedly attached to the driver  804 . The housing  806  may include a travel slot (not shown) and a screw  810 , such as a shoulder screw, to set the maximum permissible travel of the pump block  204  relative to the housing  804 . The screw  810  is inserted through the travel slot (not shown) and screwed into a threaded hole on a side of the pump block  204 . Alternatively, the screw  810  may be inserted through the travel slot (not shown) and compressed against a side of the pump block  204 . 
     At least one side of the pump block  204  may be biased against at least one side of the housing  806  to inhibit rotational motion between the pump block  204  and the housing  806  so as to reduce or eliminate backlash. For example, a spring (not shown) may be placed between the pump block  204  and the housing  806  below the screw head of the screw  810 . 
     The housing  806 , by supporting the driver  804  and only encasing a portion of the driver  804 , may reduce or eliminate expansion of the picker  200  that may result from the heat generated by the driver  804 . Decoupling or separating the picker  200  and the driver  804  may reduce or eliminate expansion of the components of the picker  100 . Furthermore, the weight of the driver  804  and external constraints  622 , such as springs or weights, bias and preload the threads of the piston  202  to reduce or eliminate change or backlash. When the external constraints  622  are springs, the springs may extend from the housing  806  to a base  812 . When the external constraints  622  are weights, the weights may be placed on top of the driver  804  or the housing  806 . 
     The drive assembly  802  may also include a home switch  808  to return the picker  200  to the home or original position. The drive assembly  802  may also include a driver knob  818  for manual operation and/or wire leads  620  for automated operation. Manual operation may include adjustments or movements to the picker or picking system by hand or may include motorized adjustments or movements to the picker or picking by an operator via a manual controller, such as a touch screen, a joystick, a directional pad or the like. 
     The picking system  800  also includes the actuator  814 , such as a piezo-electric actuator, a lead screw, or a stage. The actuator  814  may be connected to the picker  200 , such as by the base  812 , or may be connected to the drive assembly  802 . The base  812  supports the picker  200  and may connect the actuator  814  to the picker  200 . The base  812  may include a light source (not shown), such as a LED, to provide epi-, transmitted, or oblique illumination of the picker tip or tube end of the cannula. 
     The actuator  814  provides high resolution location control of the picker  200 , has a rapid response (for example, to allow for oscillation), and may be operated in an open or closed loop. The actuator  814  may provide motion along the x, y, and z axes or may provide motion along only one axis. The actuator  814  may have a travel range of 1 nanometer to more than 50 millimeters along each axis. The lower end of the travel range permits the actuator  814  to make finer adjustments (approximately 0.001-500 μm) for the picker  200  so as to better locate and pick a target analyte. The upper end of the travel range permits the actuator to make coarser adjustments (approximately 10-50 mm) for the picker  200 , such as to move the picker to different wells to draw up or expel different fluids from the different wells or receptacles, to change cannulas or replace parts when it is desirous to do so. The cannula or picker tip, for example, may be replaced by manual operation (i.e. changing out by hand) or by automated operation (i.e. by expelling the used cannula or picker tip, moving the picker over a cartridge containing at least one new cannula or picker tip, lowering the picker to mate with the new cannula or picker tip, raising the picker, and returning to a desired position). When the actuator  814  provides motion along only one axis, a second actuator (not shown) may be used to provide motion along all three axes. Furthermore, when the actuator  814  provides motion along only one axis, the second actuator (not shown) may be used for coarser adjustments, whereas the actuator  814  may be used for finer adjustments. 
     The picking system  800  may also include a mount  816  to attach the picker  200 , the drive assembly  802 , and the actuator  814  to an imaging or detection system, such as a scanner or a microscope. The mount  816  may be stationary within the imaging or detection system or may be attached to the second actuator (not shown) within the imaging or detection system. 
     The picking system  800  may also the port  312 . The port  312  may extend through the base  812 , the second end of the pump block  204  and either the first end  218  of the fitting  206  or the adapter  214  of the cannula  208 . The port  312  may be rigid. The port  312  may be connected to the loader  314 , such as a piezoelectric pump, to fill the pump volume. The loader  314  may be connected to the reservoir  316  with the tube  318 . The tube  318  may be rigid or flexible. The loader  314  may be mounted on the pump block  204 , such as by a screw, adhesive, tape, or the like. The reservoir  316  may also be mounted on the pump block  204 , such as by a screw, adhesive, tape, or the like; or, the reservoir  316  may be held or mounted on or within a scanning or imaging device. Alternatively, the loader  314  may be interchanged with a pressure sensor (not shown) to measure the pressure within the pump volume to make sure the picker  310  does not clog. 
     The picker can be composed of a variety of different materials including, but not limited to, ceramics; glass; metals; organic or inorganic materials; plastic materials; and combinations thereof. The picker tip can also be composed of a variety of different materials including, but not limited to, ceramics; glass; metals; organic or inorganic materials; plastic materials; polymers; jewels (i.e. ruby, sapphire, or diamond); and combinations thereof. Furthermore, the cannula or the picker tip may be composed of a material that is fluorescent. Additionally, the tube end of the cannula or the picker tip may be impact-resistant, hard, and dimensionally stable (i.e. axially and/or torsionally stiff). The tube end of the cannula or the picker tip may have a density that is greater than or equal to approximately 2.5 g/cc. The tube end of the cannula or the picker tip may have a hardness that is greater than or equal to approximately 80 Vickers. The tube end of the cannula or the picker tip may have a Modulus of Elasticity that is greater than or equal to approximately 65 GPa. 
     The permanent magnet includes, but is not limited to, a ring magnet, a bar magnet, a horseshoe magnet, a donut-shaped magnet, a spherical magnet, a polygon-shaped magnet, a polyhedral shape, a wand magnet, a kidney-shaped magnet, a trapezoidal magnet, a disk magnet, a cow magnet, a block or brick magnet, or combinations thereof. The magnetizable material includes, but is not limited to, metals, organic materials, inorganic materials, minerals, ferrofluids, and combinations thereof. 
     The cannula, picker tip and engagement portion may be stiff, flexible or formable. The cannula, picker tip and engagement portion may be straight, angled, curved, hooked, or any appropriate shape or configuration. The cannula, picker tip, and engagement portion may be non-clogging. 
     Detecting a Picker or Picking System 
     A picker or picking system may be used to isolate a target analyte from a suspension in or on a vessel, such as a well, a well plate, a slide, a tube, or the like, or to draw a fluid, such as a, suspension, solution or reagent, from the vessel. For example, to isolate the target analyte, the suspension suspected of containing the target analyte can be placed in the vessel. Alternatively, a fraction of the suspension, the fraction suspected of containing the target analyte, can be placed in the vessel. The vessel may be imaged to detect the target analyte and determine the location of the target analyte. After determining the location of the target analyte, an open end of the picker or picking system, such as the second end of a picking tip, the tube end of a cannula, or a tip, is guided to be located above the desired target analyte. The open end may then be moved toward the vessel until the open end eventually touches the vessel or is submerged within the suspension. 
     To properly determine the location of the open end, the vessel and picker or picking system may be imaged while guiding the open end into the proper position. During this imaging, the picking tip, cannula, or tip may oscillate back and forth. However, the picking tip, cannula, or tip may stop oscillating when in contact with the vessel or suspension. Therefore, by noting the point at which the oscillating terminates, the location of the picking surface may be determined and the open end may be properly visualized. 
     Alternatively, a sensor, such as a pressure sensor or a proximity sensor, may be placed in various locations on the imaging device, such as on a stage, in a picker or picking system component, in a turret, or the like, to detect a change in pressure or location, thereby denoting when the tip, cannula, or picking tip has contacted the picking surface. 
     Isolating a Target Analyte with a Picker or Picking System 
     A picker or picking system may be used to isolate a target analyte from a suspension. The picker or picking system may be used in conjunction with a vessel, such as a well, a well plate, a slide, or the like. For example, to isolate the target analyte, the suspension suspected of containing the target analyte can be placed in the vessel. Alternatively, a fraction of the suspension, the fraction suspected of containing the target analyte, can be placed in the vessel. The vessel may be imaged to detect the target analyte and determine the location of the target analyte. After determining the location of the target analyte, the target analyte may be isolated by the introduction of a force, such as a pressure gradient, to draw the target analyte into a picker. For example, to introduce a negative pressure gradient with the picker  200 , thereby drawing the target analyte into the cannula or picker tip, the piston  202  translates away from the vessel. To introduce a positive pressure gradient with the picker  200 , thereby expelling the target analyte or a releasing fluid, the piston  202  translates towards the vessel. 
     To remove the target analyte from a wet mount or a suspension, a negative pressure gradient may be introduced by the picker  200  after the cannula  208  is placed near, over, or above the target analyte. The negative pressure gradient causes the target analyte to move into the cannula  208 . 
     To remove the target analyte from a dry mount (i.e. a dry slide), the cannula  208  is placed over the target analyte. The cannula  208  may then be moved horizontally or orthogonally to detach the target analyte from the mount. A negative pressure gradient may then be introduced to draw the target analyte into the cannula  208 . Alternatively, the cannula  208 , after being placed over the target analyte, may oscillate up and down at any appropriate frequency to detach the target analyte from the mount, such as, for example, less than or equal to approximately 10 kHz. A negative pressure gradient may then be introduced to draw the target analyte into the cannula  208 . Alternatively, the cannula  208  may be placed over the target analyte and the target analyte may be held within the cannula without actively applying the pressure gradient. Alternatively, the cannula  208  may be placed over the target analyte and dragged across the surface of the slide, thereby dislodging the target analyte and causing the target analyte to be held within the cannula without actively applying the pressure gradient. Alternatively, a releasing fluid may be expelled by the cannula or picker tip by introducing a positive pressure within the picker. The releasing fluid, such as a detergent, a lysing agent, a permeabilizing agent, phosphate buffered saline, or the like, may be added on top of the desired target analyte so as to release the target analyte from the dry mount. A negative pressure gradient may then be introduced to draw the target analyte into the cannula or picker tip. 
     To expel the target analyte or fluid from the picker, a positive pressure gradient may be introduced by the pump. Additionally, the tube end of the cannula or the picker tip may be moved to touch the surface of the substrate onto which the target analyte or fluid is being dispense and then moved away from the surface to wick the target analyte or fluid onto the surface. 
     The target analyte may be collected, and once collected, the target analyte may be analyzed using any appropriate analysis method or technique, though more specifically intracellular analysis including intracellular or extracellular protein labeling; nucleic acid analysis, including, but not limited to, protein or nucleic acid microarrays; FISH; or bDNA analysis. These techniques require isolation, permeabilization, and fixation of the target analyte prior to analysis. Some of the intracellular proteins which may be labeled include, but are not limited to, cytokeratin (“CK”), actin, Arp2/3, coronin, dystrophin, FtsZ, myosin, spectrin, tubulin, collagen, cathepsin D, ALDH, PBGD, Akt1, Akt2, c-myc, caspases, survivin, p27 kip , FOXC2, BRAF, Phospho-Akt1 and 2, Phospho-Erk1/2, Erk1/2, P38 MAPK, Vimentin, ER, PgR, PI3K, pFAK, KRAS, ALKH1, Twist1, Snail1, ZEB1, Slug, Ki-67, M30, MAGEA3, phosphorylated receptor kinases, modified histones, chromatin-associated proteins, and MAGE. In order to fix, permeabilize, or label, fixing agents (such as formaldehyde, formalin, methanol, acetone, paraformaldehyde, or glutaraldehyde), detergents (such as saponin, polyoxyethylene, digitonin, octyl β-glucoside, octyl β-thioglucoside, 1-S-octyl-β-D-thioglucopyranoside, polysorbate-20, CHAPS, CHAPSO, (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol or octylphenol ethylene oxide), or labeling agents (such as fluorescently-labeled antibodies, Pap stain, Giemsa stain, or hematoxylin and eosin stain) may be used. 
     It should be understood that the method and system described and discussed herein may be used with any appropriate suspension or biological sample, such as blood, bone marrow, cystic fluid, ascites fluid, stool, semen, cerebrospinal fluid, nipple aspirate fluid, saliva, amniotic fluid, vaginal secretions, mucus membrane secretions, aqueous humor, vitreous humor, vomit, and any other physiological fluid or semi-solid. It should also be understood that a target analyte can be a cell, such as ova or a circulating tumor cell (“CTC”), a fetal cell (i.e. a trophoblast, a nucleated red blood cell, a fetal white blood cell, a fetal red blood cell, etc.), a circulating endothelial cell, an immune cell (i.e. naïve or memory B cells or naïve or memory T cells), a vesicle, a liposome, a protein, a nucleic acid, a biological molecule, a naturally occurring or artificially prepared microscopic unit having an enclosed membrane, a parasite, a microorganism, or an inflammatory cell. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the disclosure. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the systems and methods described herein. The foregoing descriptions of specific embodiments are presented by way of examples for purposes of illustration and description. They are not intended to be exhaustive of or to limit this disclosure to the precise forms described. Many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of this disclosure and practical applications, to thereby enable others skilled in the art to best utilize this disclosure and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of this disclosure be defined by the following claims and their equivalents: