An Automated Addressable Microfluidics Device for Minimally Disruptive Manipulation of Cells and Fluids within Living Cultures

Abstract

According to the U.S. Department of Health & Human Services, nearly 115,000 people in the U.S needed a lifesaving organ transplant in 2018, while only ~10% of them have received it. Yet, almost no artificial FDA-approved products are commercially available todaythree decades after the inception of tissue engineering. It is hypothesized that the major bottlenecks restricting its progress stem from lack of access to the inner pore space of the scaffolds. Specifically, the inability to deliver nutrients to, and clear waste from, the center of the scaffolds limits the size of the products that can be cultured. Likewise, the inability to monitor, and control, the cells after seeding them into the scaffold results in nonviable tissue, with an unacceptable product variability. To resolve these bottlenecks, we present a prototype addressable microfluidics device capable of minimally-invasive fluid and cell manipulation within living cultures. As proof-of-concept, we demonstrate its ability to perform additive manufacturing by seeding cells in spatial patterns (including co-culturing multiple cell types); and subtractive manufacturing, by removing surface adherent cells via targeted trypsin release. Additionally, we show that the device is capable of sampling fluids and performing cell "biopsies" (which can be subsequently sent for ex-situ testing), from any location within its culture chamber. Finally, the on-chip plumbing is completely automated using external electronics. This opens up the possibility to perform long-term computer-driven tissue engineering experiments, where the cell behavior is modulated in response to the minimally-invasive observations (e.g. fluid sampling and cell biopsies) throughout the whole duration of the cultures. It is expected that the proofof-concept technology will eventually be scaled up to 3D addressable microfluidic scaffolds, capable of overcoming the limitations bottlenecking the transition of tissue engineering technologies to the clinical setting.