The present invention is directed to a recirculation system for use in microfluidic centrifugal disc platforms for reusing and mixing an entire sample. The present invention features a system comprising a reservoir, an input channel, a detection array, a pressure chamber, and a recirculation channel connecting the pressure chamber to the reservoir. The recirculation channel may have a resistance lower than the channel upstream resistance. When the CD platform spins at a high RPM, the liquid may be directed from the reservoir into the pressure chamber. When the RPM of the CD platform decreases rapidly, the liquid may be directed from the pressure chamber through the channel and through the recirculation channel to the reservoir, such that the liquid travels through the recirculation channel faster than the liquid travels through the channel.

A whole-process biological detection device is provided. The whole-process biological detection device belongs to the technical field of biological detection, and includes at least one reactor, where the reactor includes at least one sample-loading unit, at least one liquid release-control unit, at least one extraction unit, at least one liquid switch-control unit, at least one liquid collection unit, at least one liquid transfer unit, at least one liquid flow-control unit, at least one liquid quantitative dispersion unit and multiple reaction cells. The product of the solution has the characteristics of high integration, no need for additional reagents, simple operation, stable and reliable, etc., thereby achieving the goal of sealing the whole process of biological detection and effectively avoiding cross-contamination between samples and equipment.

Sample preparation systems and methods are described having pump control, valve configurations, and control logic that facilitate automatic, inline preparation dilutions of a sample according to at least two dilution operating modes. A system embodiment includes, but is not limited to a first pump configured to drive a carrier fluid; a second pump configured to drive a diluent; and a plurality of selection valves fluidically coupled with the first pump and the second pump, the plurality of selection valves being configured to direct fluid flows from the first pump and the second pump according to at least two modes of operation to provide a single-stage sample dilution according to a first operating mode and to provide a dual-stage sample dilution according to a second operating mode.