Centrifugal microfluidic system for multistep assay using small amount of various samples

This paper describes a centrifuge-based dynamic microarray system using small amount of samples for application in multistep assays. The system uses meander-shaped microchannel and arrayed trapping spots to trap the samples with fluid stream generated by centrifugal force. Producing an array of samples suspended in only 1 μl of solution is achieved in 3 s with this system. After the loading solution is introduced, air is infused into the microchannel, keeping the sample and loading solution at the trapping spot. This air infusion allows us to immobilize and isolate the trapped samples suspended in the loading solution. In addition, the solution around the trapped sample can be repeatedly exchanged by introducing another solution. This system is applicable for multistep assays using small amount of rare samples.