Three dimensional MEMS microfluidic perfusion system for thick brain slice cultures.

In vitro tissue culture models are often benchmarked by their ability to replicate in vivo function. One of the limitations of in vitro systems is the difficulty in preserving an orchestrated cell population, especially for generating three-dimensional tissue equivalents. For example, tissue-engineering applications involve large high-density constructs, requiring a perfusing system that is able to apply adequate oxygen and nutrients to the interior region of the tissue. This is particularly true with respect to thick tissue sections harvested for in vitro culture. We have fabricated a microneedle-based perfusion device for high-cell-density in vitro tissue culture from SU-8 photosensitive epoxy and suitable post-processing. The device was tested for its ability to improve viability in slices of harvested brain tissue. This model was chosen due to its acute sensitivity to disruptions in its nutrient supply. Improved viability was visible in the short term as assessed via live-dead discriminating fluorescent staining and confocal microscopy. This perfusion system opens up many possibilities for both neurobiological as well as other culture systems.