Flexible microfluidic devices supported by biodegradable insertion scaffolds for convection-enhanced neural drug delivery

Convection enhanced delivery (CED) can improve the spatial distribution of drugs delivered directly to the brain. In CED, drugs are infused locally into tissue through a needle or catheter inserted into brain parenchyma. Transport of the infused material is dominated by convection, which enhances drug penetration into tissue compared with diffusion mediated delivery. We have fabricated and characterized an implantable microfluidic device for chronic convection enhanced delivery protocols. The device consists of a flexible parylene-C microfluidic channel that is supported during its insertion into tissue by a biodegradable poly(DL-lactide-co-glycolide) scaffold. The scaffold is designed to enable tissue penetration and then erode over time, leaving only the flexible channel implanted in the tissue. The device was able to reproducibly inject fluid into neural tissue in acute experiments with final infusate distributions that closely approximate delivery from an ideal point source. This system shows promise as a tool for chronic CED protocols.