Design Considerations of Enzymatic Electrochemical Sensors for Endovascular Catheter-Mounted Flow Systems
Name
GeorgeAkpenyi-jgeorgea-smme-meche-2026-thesis.pdf
Size
4.48 MB
Format
Adobe PDF
Checksum (MD5)
fdce9fab91369834d6142dce8b556722
Author(s)
George-Akpenyi, Jesse
Advisor(s)
Edelman, Elazer R.
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
Cardiovascular diseases are the leading cause of mortality and morbidity globally, with cases only continuing to rise. Of these diseases, many fatally progress into cardiogenic shock, defined by multi-organ failure due to a lack of proper perfusion with reduced cardiac output and elevated intracardiac pressures. This highly morbid condition has a 30-day mortality rate of about 50% post-treatment. Technological advances have increased the deployment of mechanical circulatory support (MCS) devices to treat cardiogenic shock in ways that traditional drug-based therapies cannot. MCS offers greater unloading of the heart while reducing myocardial oxygen demand, but its use has plateaued as the clinical understanding to guide operation is limited. The core issue lies in the limitations of open-loop control for MCS devices, which can be addressed by incorporating closed-loop feedback control. There is progress being made in hemodynamic monitoring for this purpose, but biochemical diagnostics remain infrequent and time-consuming, restricting their utility as a feedback signal. This is problematic as blood biomarkers are crucial in evaluating the progression or regression of shock which correlates with end-organ tissue perfusion and organ dysfunction. The indwelling intraventricular placement of an MCS device is the ideal location for a robust set of biosensing elements, which would eliminate several restrictions on biochemical diagnostics as a feedback source. The incorporation of multi-analyte enzymatic electrochemical sensors onto endovascular catheters may begin a new era of biomarker-based closed-loop feedback control for MCS. As a small step in toward that future, this project identifies physical flow qualities that influence the functionality of a catheter-mounted sensing system by measuring the signal response changes of a de-novo set of lactate biosensors attached to a Boston-Scientific catheter in a flow-loop test bench. Lactate was chosen as the target analyte for its clinical importance in hypoxic conditions, but the overall fabrication process of the sensors was made adjustable to allow for various multi-analyte sensor layouts and catheter sizes. The fabricated lactate sensors had a sensitivity of 38.6 µA/cm2/mM, with a linear response for concentrations between 0.1 mM to at least 10 mM, with a limit of detection of at most 0.01 mM. Our findings elucidated how variations in local fluid velocity, flow pulsatility, fluid viscosity and the placement region on a catheter can significantly alter how rapidly the enzymatic sensors responded to lactate level changes. The settling time greatly increased (~10 seconds to ~10 minutes) when compared to still conditions, and suboptimal local flow conditions (high fluid velocity, low pulsatility, high viscosity, highly turbulent/disturbed flow regions) reduced the rate of sensor response by as much as 80%. This reflects the diffusion-limited nature of the constructed sensors. Despite this reduction in responsiveness, the experiments did not show any significant change to sensor precision or accuracy when allowed to settle under steady state flow within an acceptable time scale for clinical relevancy (under 20 minutes). Thus, enzymatic electrochemical sensors mounted on catheters are a viable method of improving the fidelity and frequency of blood biochemical diagnostics, ideally positioned in lower velocity regions of the vasculature.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
In Copyright - Educational Use Permitted
Copyright retained by author(s)
Persistent DSpace Link
