Biosensors offer wide opportunities for threat agent analysis, but practical analytical systems require these sensors to be integrated with pre- and post analytical steps to enable simplified, seamless operation. Perhaps the most important of these steps relates to sample handling and presentation. Advances in microfluidics now offer a realistic means for simplified, practical handling with the facility for compressing existing analytical platforms in biosensing. Small volume handling can not only allow for miniaturisation, but flow at this scale enables a different type of flow profile and the a facility for direct liquid-liquid exchange. Basic flow principles in microflow are presented followed by a description of aqueous/organic flows and how they cab be used both for solute partitioning and in situ membrane formation. The potential value of miniaturised separation membranes is described, including for sample cleanup, handling and biosensor protection. Finally, examples of sensor integration into microfluidic structures are given as pointer towards future developments. Overall, the chapter seeks to rebalance the traditional emphasis on biosensor design by highlighting the importance of controlled sample presentation as a potential route to low maintenance biosensors with improved response characteristics. © 2016, Springer International Publishing Switzerland.