Abstract: The present invention relates generally to the control of fluid flow rate and direction on a microfluidic device. In particular, the present invention provides an integrated valveless microfluidic device, where directional fluid control is controlled using off-chip remote valve switching and fluid flow rate changes are controlled using on-chip flow-rate changing fluid reservoirs. The present invention provides methods and systems for directional fluid control and control of fluid flow rate in an integrated microfluidic device which enables processes with different flow rates to be performed on one device without the need of on-chip valves.

Abstract: Disclosed herein are methods for purification of RNA from a sample. The RNA can be total RNA or mRNA. The method involves preparing the sample in a solution of lysis buffer and depositing into a first end of a lysis straw such that the sample solution flows through the matrix of the lysis straw and is eluted from the opposite end of the lysis straw, and depositing the eluted material into a first end of a solid phase extraction (SPE) straw, such that the deposited solution flows through the matrix of the SPE straw towards the opposite end of the SPE straw, and eluting the RNA from the SPE straw by depositing a solution of elution buffer, into the first end of the SPE straw, such that the deposited solution flows through the matrix of the SPE straw and is eluted from the opposite end of the SPE straw, wherein purified RNA from the sample is present in the eluate of the SPE straw.