The Design Of Cell Chip Based On Microelectrode Arrays And Its Applications In The Study Of Cardiac Physiology

Cell-based biosensors (CBBs), taking live cells and transducers as primary and secondary sensing elements respectively, exhibit the characteristics of high sensitivity, low cost and high-throughput detection. They have been widely applied in the fields of environmental toxicity, food safety and pharmacological screening, and gradually commercialized. Microelectrode arrays (MEAs), a type of cell-based biosensors, are specially to detect the extracellular electrophysiological activities of electrigenic cells including cardiomyocytes and neuronal networks. With outstanding qualities such as non-invasiveness to cells, fast response, uncomplicated fabrication process and scalability, it has been a research hotspot. In this paper, we designed some chips with multiple functions based on microelectrode arrays to study the cardiac physiology and exploit the drug-induced cardiotoxicity. These chips can also be used to study other types of cells.The work mainly consisted of three parts as follows:Firstly, we systematically explored the extracellular detection mechanism of microelectrode array and achieved the design.Based on the electrochemical attributes of metal-electrolyte interface and ion-channel model, the point-contact model was built up to simulate the relationship between transmembrane action potential and extracellular field potential by software tool. According to the simulation result, we achieved chip design and found it with good biocompatibility and stability. It successfully recorded the extracellular field potential of cardiomyocytes hippocampal neurons and olfactory epithelium. The experimental results showed high fitness with the simulated result.Secondly, we firstly designed the chip of multi-scale electrode array (MSEA) to detect the cardiac excitation-contraction coupling as a whole system.Based on the special attributes of cardiomyocytes, we changed the common microelectrode array and expanded the diameter of electrodes from several tens micrometers to millimeter scale. It is observed that the general microelectrodes could detect the extracellular field potentials, as well as the millimeter scale electrode can detect the mechanical contraction whose amplitude and time duration showed positive relationship with electrode area. Furthermore, the contractile detection was confirmed by a type of microtubule inhibitor. The generation mechanism of hump was analyzed and it resulted from the change of electrode half-cell potential due to the mechanical perturbation on the charge in double electric layers.According to the study, the MSEA integrated with micro-and milli-scale electrodes could detect the extracellular field potential and mechanical contraction synchronously in electric way. It could be a platform for cardiac pharmacology screening targeted with the excitation-contraction coupling.Thirdly, we raised the method of jointly studying the extracellular field potential and physical state.Based on the method, the cell chip integrated with microelectrode array and interdigitated electrodes was designed. To avoid the electric disturbance between these two types of sensors, the whole recording process was scheduled in a time-switch way. The chip was used to recording the extracellular field potential and cell-electrode impedance change of cardiomyocytes under the treatment of anthracycline anticancer drug doxorubicin. The analysis showed that most of the symptoms extracted from the recording results by chip ExCell occurred in the clinical treatment of histological results, which proved the validity of the designed chip. Additionally, we proposed the temporal spectrum of the symptoms of drug-induced cardiotoxicity, which could clearly map the changing process of the symptoms when drugs acting on cardiomyocytes.Correspondingly, we built up a multi-function automatic analyzing system based on the integrated chip. With these work, it explored the methods of detection and evaluation on cardiotoxicity preliminary.