Multifunctional CMOS chip in open microfluidic system
Novel multifunctional CMOS microelectrode array has been integrated into an open microfluidic system. The array can be used in hanging-drop mode for in situ microtissue readouts and in standing-drop mode like a conventional microelectrode array.
The hanging-drop method is used to cultivate microtissues at an air–liquid interface and proves to be effective for microtissue formation and maintenance. In a recent paper, titled "Seamless integration of CMOS microsensors into open microfluidic systems", (R. Bounik, et al.., Lab on a Chip 2025, 25, pp. 2205 - 2221.), we described a combination of microfluidics with microelectronics in complementary metal-oxide-semiconductor (CMOS) technology. We developed a novel multifunctional CMOS microelectrode array (MEA) that can be integrated into an open microfluidic system. The device can be used in hanging-drop mode for in situ microtissue readouts and in standing-drop mode like a conventional MEA. The CMOS-MEA chip features two reconfigurable electrode arrays with 1024 electrodes each, and enables electrophysiology, impedance spectroscopy, and electrochemical sensing to acquire a broad spectrum of biologically relevant information. We fabricated the chip using a 0.18 μm CMOS process and developed a strategy to integrate the CMOS-MEA chip into the open microfluidic system within a larger overall effort to incorporate discrete CMOS sensors into microfluidic devices. Proof-of-concept experiments demonstrated the capability to perform electrophysiology and impedance spectroscopy of human induced pluripotent stem cell (hiPSC)-derived cardiac microtissues, as well as electrochemical sensing of different analytes including hydrogen peroxide and epinephrine.