Convective flow effects on DNA biosensors.

We explore theoretic limits of convective flux effects, as a function of species concentrations and sample volume, in biosensing systems containing target species with differing affinities. A finite element method is used to simulate mass transport of DNA through a microfluidic chamber to the sensing surface where hybridization of DNA is modeled using the corresponding kinetic equations. Our results show enhancements due to convection are controlled by the concentration and sample volume of the lower affinity species, while the upper-limit of the enhancements are determined by the concentration and sample volume of the higher affinity species. Additionally, enhancements are controlled by the degree of competition between the two species, which is related to the total fraction of binding sites used.