A Method For Parallel, Automated, Thermal Cycling of Submicroliter Samples

A large fraction of the cost of DNA sequencing and other DNA-analysis processes results from the reagent costs incurred during cycle sequencing or PCR. In particular, the high cost of the enzymes and dyes used in these processes often results in thermal cycling costs exceeding $0.50 per sample. In the case of high-throughput DNA sequencing, this is a significant and unnecessary expense. Improved detection efficiency of new sequencing instrumentation allows the reaction volumes for cycle sequencing to be scaled down to one-tenth of presently used volumes, resulting in at least a 10-fold decrease in the cost of this process. However, commercially available thermal cyclers and automated reaction setup devices have inherent design limitations which make handling volumes of <1 microL extremely difficult. In this paper, we describe a method for thermal cycling aimed at reliable, automated cycling of submicroliter reaction volumes.