IMSIS: an instrumented microphysiological system with integrated sensors for monitoring cellular metabolic activities

Abstract

Well plates are widely used in biological experiments, particularly in pharmaceutical sciences and cell biology. Their popularity stems from their versatility to support a variety of fluorescent markers for high throughput monitoring of cellular activities. However, using fluorescent markers in traditional well plates has its own challenges, namely, they can be potentially toxic to cells, and thus, may perturb their biological functions; and it is difficult to monitor multiple analytes concurrently and in real-time inside each well. In this dissertation, an Instrumented Microphyiological System with Integrated Sensors (IMSIS) platform is presented. The IMSIS platform is supported by integrated bioelectronic circuits and a graphical user interface for easy user configuration and monitoring. The IMSIS platform currently incorporates O2, H2O2, and pH sensors inside each well, allowing up to six wells to perform concurrent non-destructive and label-free measurements in real-time. The system has integrated microfluidics to maintain its microphysiological environment within each well. The miniaturized design ensures portability, suitable for small offices and field applications. The IMSIS platform is equipped with a 14-bit ADC and read channel bioelectronics with the signal-to-noise ratio (SNR) of 79 dB, 112 dB, and 48 dB for measuring oxygen consumption rate (OCR), hydrogen peroxide production rate (HPR), and extracellular acidification rate (ECAR), respectively. Furthermore, the scalable design of the architecture allows easy expansion to accommodate a higher throughput in the future. A graphical user interface was developed to provide a dashboard control by users for system operation. The versatile platform supports electrochemical sensing techniques such as amperometry, chronoamperometry, and potentiometry, with a reference electrode voltage range of ±1 V. The IMSIS platform has been used to monitor the real-time metabolic activities of various biological samples, including bovine, equine, and human oocytes, bovine and equine embryos, as well as isolated mouse cardiac mitochondria. The IMSIS platform has successfully shown its capability to simultaneously measure OCR, ECAR, and HPR both in the sample's basal state and in response to external stimuli, such as oligomycin. The design of the IMSIS platform and the experimental results underscore its significant potential for diverse clinical and research applications. These include embryo quality assessment for assisted reproductive technology (ART), investigation of the effects of obesity-induced mitochondrial dysfunction, and analysis of cancer tumors and their metabolic response to therapeutics.