Design, Fabrication, and Testing of a Hybrid CMOS/PDMS Microsystem for Cell Culture and Incubation

We discuss the design, fabrication, and testing of a hybrid microsystem for stand-alone cell culture and incubation. The micro-incubator is engineered through the integration of a silicon CMOS die for the heater and temperature sensor, with multilayer silicone (PDMS) structures namely, fluidic channels and a 1.5-mm diameter 12-$\mu$L culture well. A 90-$\mu$m-thick PDMS membrane covers the top of the culture well, acting as barrier to contaminants while at the same time allowing the cells to breath and exchange gases with the ambient environment. The packaging for the microsystem includes a flexible polyimide electronic ribbon cable and four fluidic ports that provide external interfaces to electrical energy, closed-loop sensing and electronic control as well as solid and liquid supplies. The complete structure has a size of (2.5$\,\times\,$2.5$\,\times\,$0.6) cm $^{3}$. We have employed the device to successfully culture BHK-21 cells autonomously over a three day period in ambient environment.