Micromachined Fluid Transfer Devices for Molecular Screening

DESCRIPTION (provided by applicant): The lack of rapid, inexpensive and accurate fluid transfer technology for volumes below one microliter is becoming a limiting factor in attempts to increase the sample density and assay accuracy of many high throughput processes. High throughput experiments such as compound library reformatting, nanoliter fluid transfer, assay miniaturization and molecular library screening would all greatly benefit from a more accurate and faster fluid transfer technology. To provide a viable alternative to nL dispensing technology such as metal pin tools, which have relatively imprecise fluid transfers with %CVs of >15%, or very expensive and relatively slow acoustic dispensing, this proposal proffers a design for a parallel fluid transfer head containing 384 highly precise micromachined silicon fluid transfer devices (FTDs). Prototype silicon FTD arrays, with sharp, pointed silicon tools designed to puncture foil or polymer seals on a microtiter plate and withdraw the sample in a single operation, have been fabricated. Fluid transfer dilution experiments using Rhodamine 6G in DMSO to simulate compound library reformatting protocols, show that the prototype silicon pin tool array transfers 100nL samples in parallel with %CVs of 2-3%. Once the silicon FTDs are fabricated, it is relatively straightforward to prepare a polymer FTD employing the silicon FTD in a micromolding process: the silicon FTDs are used to prepare a positive silicon master mold onto which a nickel-cobalt alloy is electrodeposited (i.e. electroformed) to create a metal negative which is used to compression mold a polymer part identical to the silicon original. After initial testing of fluid transfer in the 1 to 500 nL range in a variety of designs at Parallel using dye transfer and a plate scanner, the most encouraging designs in both silicon and polymer will be transferred to collaborator Matrical, Inc. and evaluated in a series of experiments to determine their efficacy in nanoliter fluid transfer and compound library reformatting. In summary, micromachined silicon or polymers tool sets have been designed which will provide a much faster, accurate and more robust means for passive sub-nanoliter fluid transfer at an estimated price equal to or less than any of the current technologies. The instruments developed in this proposal will facilitate molecular library screening, compound library reformatting and any other methodology that requires handling small volumes of liquid. By making devices that possess superior performance capabilities at lower prices than existing technologies, it is anticipated that even the most modestly budgeted of laboratories will have access to these tools. The increases in productivity and efficiency made possible by these devices will enable rapid progress in the screening and characterization of new methods for the prevention, detection, and treatment of human disease.