Porous Titania Thin Film Microfluidic Devices for Medical Diagnostics

We present a new methodology using highly wetting porous titania films to develop microfluidic devices which can be employed for medical diagnostics. Capillary flows through thin porous media are attractive for small-scale liquid transport systems. Capillary flows show different characteristics depending on the medium, however, for most media it is challenging to realize arbitrary shapes and spatially functionalized micro-structures with variable flow properties. In this work, a new fabrication technique with corresponding flow equations have been developed to design porous films for capillary flow driven microfluidic devices. We employ breakdown anodization to produce highly wettable porous thin films, with predictable capillary flows. The porous thin films are created on microfluidic channels produced by conventional soft lithography and we demonstrate their efficacy with an analysis of an artificial urine sample.