Herringbone-like hydrodynamic structures in microchannels: A CFD model to evaluate the enhancement of surface binding.

Selected adsorption efficiency of a molecule in solution in a microchannel is strongly influenced by the convective/diffusive mass transport phenomena that supply the target molecule to the adsorption surface. In a standard microchannel with a rectangular cross section, laminar flow regime limits the fluid mixing, thus suggesting that mass transport conditions can be improved by the introduction of herringbone-like structures. Tuning of these geometrical patterns increases the concentration gradient of the target molecule at the adsorption surface. A computational fluid dynamic (CFD) study was performed to evaluate the relation between the geometrical herringbone patterns and the concentration gradient improvement in a 14 mm long microchannel. The results show that the inhomogeneity of the concentration gradient can provide an improved and localized adsorption under specific geometrical features, which can be tuned in order to adapt the adsorption pattern to the specific assay requirements.