Many of our customers want to make liquid to dry plate transfers to make mini-microarrays in a single well for multiplexing assays.  By their very nature these transfers only leave a small volume remaining on the plate.  The amount remaining depends on the surface tension of the plate, the transfer liquid and the pin (diameter and shape).  We have found that reasonable results can be obtained if you use an aqueous spotting buffer and a polypropylene surface (CV's less than 9%).  DMSO spotting buffers leave much less liquid on the dry plate and when used with polystyrene plates the CV's are significantly higher. 

The plate to the right was spotted using a 50 nl slot pin (FP1CS50) transferring oligo DNA in an aqueous spotting buffer to a specially treated polypropylene plate.  Our customer in this case wanted to place 42 individual spots in the bottom of each well of a 96 well microplate.  Spot diameter = 0.55 mm. Volume transferred to the spot = 5.85 nl

The photo on the right is the result of a dilution hybridization assay of the Oligo spots with a labeled DNA that can be detected optically and quantitated.

Enlargement of the third column of the above photo.