Liquid dispensing apparatus and method

Abstract

A multiwell plate for microarraying comprising a self-sealing lower membrane and optionally also a self-sealing upper membrane. Spotting is performed by pushing a pin down through the liquid and then on to pierce the self-sealing lower membrane. A slide having an upper spotting surface is arranged under the well plate. The liquid sample forced through the lower membrane by the pin tip can thus be deposited directly onto the spotting surface. The pin is then withdrawn upwards through the lower membrane, which automatically reseals preventing further loss of liquid. The optional resealable upper membrane also prevents loss of sample liquid by evaporation and spillage. By contrast to the prior art, there is the major advantage that the pin head does not have to traverse between the well plate and slide to collect sample liquid, thus dramatically increasing operational speed for an automated microarraying apparatus employing the multiwell plate. Excellent spot reproducibility is also observed.

1 - 4 . (canceled)  
     
     
         5 . A well plate comprising: 
 an upper surface;    a lower surface;    an array of wells extending between the upper surface and the lower surface;    a lower membrane extending over the lower surface to form a self-sealing, liquid-tight base for the wells.    
     
     
         6 . A well plate according to  claim 5 , wherein the lower membrane is formed of a single sheet of material.  
     
     
         7 . A well plate according to  claim 5 , wherein the lower membrane is formed of multiple sheets.  
     
     
         8 . A well plate according to  claim 7 , wherein there is one sheet for each of the wells.  
     
     
         9 . A well plate according to  claim 5 , further comprising an upper membrane extending over the upper surface to form a top for the wells.  
     
     
         10 . A well plate according to  claim 9 , wherein the upper membrane is made of self-sealing material.  
     
     
         11 . A well plate according to  claim 5 , further comprising a removable cover extending over the upper surface to form a top for the well plate.  
     
     
         12 . A well plate according to  claim 5 , wherein the array of wells conforms to a square grid having a grid spacing of one of: 2.25 and 4.5 millimeters.  
     
     
         13 . A well plate according to  claim 5 , wherein the array of wells has one of: 96, 384 and 1536 wells.  
     
     
         14 - 20 . (canceled)