The development of a rapid, miniaturized, and efficient on-chip sample preparation for "real" sample analysis remains a major bottleneck for the realization of a lab-on-a-chip approach in point-of-care diagnostics. We developed a fully integrated and automated labon-a-disc using centrifugal microfluidics to provide a "sample-in and answer-out" type of biochemical analysis solution with simple, size-reduced, and cost-efficient instrumentation.1 Here, I present various examples of the fully integrated "lab-on-a-disc" developed for broad applications ranging from medical diagnostics to food, environment, and energy applications (Fig. 1A). Active valves on a spinning discWe pioneered the concept of laser-irradiated ferrowax microvalves (LIFM) with colleagues at Samsung Advanced Institute of Technology (SAIT), which provided a simple and robust tool for obtaining fluidic control on a spinning disc.2 The key achievement of this work was the rapid and wireless actuation of multiple valves by simple laser irradiation on nanoheaters, which are 10-nm-sized ferro-oxide nanoparticles dispersed in paraffin wax (Fig. 1B).2 The response time of both the normally open and normally closed valves was very short, and the actuation of the valves was independent of the sequence of the spin speed, sample type, or material properties of the substrates. More recently, we

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We present a novel fully integrated centrifugal microfluidic device with features for target antigen capture from biological samples, via a bead-based enzyme-linked immune-sorbent assay, and flow-enhanced electrochemical detection. The limit of detection (LOD) of our device for the C-reactive protein (CRP) was determined to be 4.9 pg mL(-1), a 17-fold improvement over quantification by optical density. The complete sample-to-answer protocol of our device is fully automated and takes less than 20 min. Overall, the presented microfluidic disc adds to the comparatively small number of fully integrated microfluidic-based platforms that utilize electrochemical detection and exemplifies how electrochemical detection can be enhanced by flow to successfully detect very low levels of biomarkers (e.g. pg mL(-1)).

This article draws upon a novel large-volume device to further illustrate the challenges in combining microfluidics structures with large-volume samples and the implications for sample-driven microfluidics systems.