In this work the development of novel flow control methods in centrifugal microfluidic systems for the nucleic acid testing are demonstrated. Nucleic acids make excellent biomarkers for the identification of numerous diseases, but their detection is a lengthy and labour intensive process. Centrifugal microfluidics has emerged as a highly useful tool in the area of biomedical diagnostics; however there are still limitations when it comes to sample preparation on these Lab-on-a-Disc systems. This is especially important in nucleic acid testing, where the main bottleneck in performing these processes on microfluidic devices is in sample preparation. Nucleic acid testing can be broken into three stages; extraction, purification and detection. To this end, this work outlines the development of two novel centrifugal routing systems for nucleic acid purification, through the integration of functional materials. The first is a solvent-selective router which integrated two solvent specific membrane valves. The capability of the system to purify total RNA with significant integrity and concentration was shown. The second system integrated multi-layer Graphene Oxide (GO) membranes into our Lab-on-a-Disc devices. Using this, two unique properties of the GO were investigated; its solvent selectivity and air impermeability. Finally, a novel, centrifugo-pneumatic scheme for solvent-selective routing of organic and aqueous flows was demonstrated. Also shown is the development of two separate extraction platforms. The first was a centrifugo-pneumatic ‘μHomogenizer’, which implements a 3-phase fluid extraction protocol of RNA. This system integrates chemical lysis and separation of the RNA containing aqueous phase and shows significant improvement over its time-consuming and labour intensive benchtop alternate. The second was the development of a mechanical lysis method that utilises a rotor stator grinding mill driven by the spindle motor. This system can be used for general lysis of a wide range of bacteria but would be of significant benefit for armoured cells.