Bioartificial Liver Process Monitoring and Control Systems with Integrated Systems Capability

Abstract

Monitoring and control of a bioartificial liver (BAL) support system have the potential to allow for maximization of device bioactivity and protection of both patient and device from untoward consequences of a complex hemoperfused fluidic process, such as coagulation, leakage, or decreased metabolic output. In this work, an integrated embedded systems controller and associated experimental platform were developed to allow for simultaneous monitoring and control of the physical environment of the BAL support system to ensure optimal and sustained hepatic metabolic function and to allow for simplified recording of experimental data. The user interface and core embedded system kernel were developed with rapid prototyping software tools and allowed for operation of easily modified user interface panels. BAL environment monitoring consisted of real-time recording of ambient and reactor temperatures, reactor inlet pressure, the presence of bubbles in the prereactor inlet tubing, and aqueous oxygen tension. Environmental parameters under direct real-time control included reactor inlet flow rate, ambient temperature, and adaptive control of flow rate in response to changes in either inlet pressure or outlet oxygen tension. Use of embedded system integration techniques will facilitate subsequent BAL studies that are dependent on scale-up of reactor size and number, fluidic complexity, and the degree of parallelism such as large animal studies and, ultimately, human clinical studies. In addition, further studies of the effects of flow rate, shear, oxygenation and metabolic substrate on real-time cellular respiration can be pursued with the use of real-time ruthenium oxymetry, as described in this article.