(193s) An All-in-One High Throughput Microfluidic Platform for Cell Culture and Migration Control

Authors: 
Pham, L. Q., New Jersey Institute of Technology NJIT
Voronov, R., New Jersey Institute of Technology NJIT
Abatemarco, P., New Jersey Institute of Technology NJIT
Chege, D., New Jersey Institute of Technology
Dijamco, T., New Jersey Institute of Technology
High-throughput and automated cell culture, conditioning, and screening platforms are becoming increasingly attractive with the advent of lab-on-a-chip technology which synergically couples the understanding of microfluidics with integrated sensing and controlling automation. Even though earlier works have demonstrated various platforms of either generating well-defined flow rates or controlling temperature at high consistency, the combination of these two ends in one single unit has not been established. Herein, we demonstrate an automated system that enables the on-demand regulation of both flow rate and temperature of a microfluidic system using a proportional-integral-derivative (PID) mechanism. As a proof-of-concept, we provided temporally and spatially high-resolution controls over flow and temperature in a microfluidic device which have two parallel flow channels (50 µm high (H) and 200 µm wide (W)) connected by an array of 50 diffusion channels (20 (W) x 15 (H) µm). As measurement is concerned, flow rate is calculated from the pressure drop inside these flow channels, which is measured via differential pressure sensors while temperature is measured by RTD sensors. These sensors are connected to a computer through appropriate IO modules. Fluctuations in these parameters are handled by Matlab code which could both communicate with high-precision microfluidic valves in regulating the flow rate and a custom-made ITO-glass heating unit in compensating for a temperature difference. With this platform, we were able to maintain flow rates as small as 2 µL min-1 in both flow channels. Temperature in the chip could be kept constant at 37 ± 0.1 °C. Following that, fibroblast cell chemotaxis experiment was performed in the chip. Platelet-derived growth factor-BB (PDGF-BB) was introduced in one of the flow channels and cells were seeded in another. A stable well-defined gradient of the chemoattractant was established inside diffusion channels. Fibroblasts were found to migrate inside the diffusion channels following the gradient of PDGF-BB over the course of 24 hours.