Control of sequential fluid delivery in a fully autonomous capillary microfluidic device

Microfluidics and miniaturization of biosensors are fundamental for the development of point-of-care (PoC) diagnostic and analytical tools with the potential of decreasing reagent consumption and time of analysis while increasing portability. However, interfacing microfluidics with fluid control systems is still a limiting factor in practical implementation. We demonstrate an innovative capillary microfluidic design that allows sequential insertion of controlled volumes of liquids into a microfluidic channel with general applicability. The system requires only the placing of liquids at the corresponding inlets. Subsequently, the different solutions flow inside the microfluidic device sequentially and autonomously without the use of valves using integrated capillary pumps. The capillary microfluidic system is demonstrated with a model immunoassay.