Leaf-templated, microwell-integrated microfluidic chips for high-throughput cell experiments.

As an alternative to conventional cell culture and animal testing, an organ-on-a-chip is applied to study the biological phenomena of organ development and disease, as well as the interactions between human tissues and external stimuli such as chemicals, forces and electricity. The pattern design of a microfluidic channel is one of the key approaches to regulate cell growth and differentiation, because these channels work as a crucial vasculature system to control the fluidic flow throughout the organ-on-a-chip device. In this study, we introduce a novel leaf-templated, microwell-integrated microfluidic chip for high-throughput cell experiments, consisting of a leaf-venation layer for fluent fluid flow, and a microwell-array layer for cell to reside. Computational fluid dynamics analysis was carried out to study the fluidic flow within leaf-venation network, which was further used to optimize the design of microwell arrays. A simple leaf-venation-mold-based microreplication method was developed to transfer the intact native leaf venation network into leaf-venation layer and 3D printing technology was used to fabricate the microwell-array layer. The layers were then assembled and used for perfusion culture, showing that leaf-templated microfluidic channels provided a sufficient culture medium for cells within each microwell. These results indicate a novel and effective strategy to generate a biomimetic microfluidic chip with an effective vascular transport system for high-throughput cell experiments.