This Is AuburnElectronic Theses and Dissertations

Magnetoelastic Sensor Systems in Biomarker Sensing Applications




MacLachlan, Alana

Type of Degree

PhD Dissertation


Materials Engineering

Restriction Status


Restriction Type


Date Available



Biosensors are receptor-transducer devices which convert biological responses into readable signals. Biosensor design and development have drawn increasing attention due to the extensive range of possible applications, including disease diagnosis, human health monitoring, environmental sensing, and food quality control. Biosensors are classified broadly, based on target analyte, energy requirements, signal conversion, applications, and sensor material. Magnetoelastic (ME) sensor technology has been investigated for many applications, including sensing of strain, force, and stress, and specifically in biological areas for monitoring of degradation rate of bone, ammonia and glucose levels, bacterial growth, and blood viscosity/coagulation. ME sensing platforms are attractive due to their low cost, quick response time, high sensitivity, passivity, and wireless transduction and sensing ability.1 Here, we tailor and apply ME sensors to two different biological targets for human health and safety. First, we demonstrate the utility of ME sensing in food safety applications through the capture of Salmonella Typhimurium from produce wash water. A 3D phage-based ME filter system was designed and fabricated to selectively capture and concentrate Salmonella, while allowing non-target molecules to pass through without clogging. We demonstrated a capture rate of over 90%, utilizing 20,000 ME filter elements. Second, we report the application of ME sensors for the capture of circulating tumor cells, a sign of cancer metastasis and measure of disease prognosis. Successful antibody functionalization of the sensor surfaces and capture of circulating tumor cells were achieved. We demonstrated a limit of detection of 9 cells. Third, a microfluidic device utilizing ME sensors as filtration elements was fabricated. The design considered fluid flow properties on the microscale, and they were leveraged to provide increased cell-sensor binding. We believe the ME sensor platform to be a versatile tool for sensing multiple biological targets, leading to safer food, early cancer diagnosis, and disease state monitoring, and opens the door for more personalized medical treatments.