Microarray Screening: Scott L. Diamond, PhD.
Diamond laboratory has developed a methodology to screen chemical
libraries on microarrays (Gosalia and Diamond, PNAS 2003).
Chemical compounds within individual nanoliter droplets of glycerol
can be microarrayed onto glass slides at 400 spots/cm2.
Using aerosol deposition, subsequent reagents and water are metered
into each reaction center in order to rapidly assemble diverse multicomponent
reactions without cross-contamination or the need for surface linkage.
This proteomics technique allows for the kinetic profiling of protease
mixtures, protease – substrate interactions, and high throughput
Exploiting the low volatility of glycerol droplets on glass, we
have created discrete reaction volumes via contact printing. Each
droplet had an average volume of 1.6 nL after microarraying. A 16x24
array of 200 um diameter spots with 500 µm center-to-center
spacing, equivalent to a 384-well plate format, occupied less than
1-cm2. In kinetic applications on a microarray, the need
to initiate tens of thousands of reactions at once is not easily
accommodated by the use of piezo dispensing micropipettes or ink-jet
engines that have exacting surface tension or viscosity requirements
and are prone to clogging. To solve the problem of rapid sample
delivery to these small nonspreading droplets, we deposited onto
the arrays using aerosol deposition. In this approach, the aerosolization
of the sample resulted in a fine mist with a median droplet diameter
of 18 µm (~3 pL). Aerosol droplets deposited evenly on and
around the glycerol spots and rapidly evaporated within 7 seconds
without mixing between spots.