  Dried blood spot (DBS) has risen in popularity due to the ease of sampling,
storing, shipping and more. Despite those advantages, recovery of the dried
blood in solution for analysis is still a bottleneck as it is manual,
time-consuming and leads to high dilutions. To overcome those issues, we have
developed a microfluidic chip allowing reversible opening, holding hermetically
DBS and forcing the elution buffer through the thickness of DBS. The new
technique, validated with clinical samples, is automated, fast, robust,
precise, compatible with in-line analysis and leads to a highly concentrated
extraction. Moreover, by using model experiments with fluorescein solutions, we
show that the elution process is governed by an advection-diffusion coupling
commonly known as Taylor dispersion. This new technique could open the way to a
new generation of analytical devices to quantify analytes in DBS samples for a
wide range of applications.
