Bio-sensors implanted in the body are revolutionizing healthcare. How to power these sensors is an open challenge. One promising option is to harvest small amounts of energy from the body itself, effectively making the sensor self-powered. We derived and tested a model for a self-powered sensing in a human airway, where measuring subtle changes in breathing could, e.g., trigger early interventions for patients with severe asthma.
Authors: Lucy Fitzgerald, Luis Lopez Ruiz, Joe Zhu, John Lach, & Daniel Quinn
Abstract: Piezoelectric materials are widely used to generate electric charge from mechanical deformation or vice versa. These strategies are increasingly common in implantable medical devices, where sensing must be done on small scales. In the case of a flow rate sensor, a sensor’s energy harvesting rate could be mapped to that flow rate, making it ‘self-powered by design (SPD)’. Prior fluids-based SPD work has focused on turbulence-driven resonance and has been largely empirical. Here, we explore the possibility of sub-resonant SPD flow sensing in a human airway. We present a physical model of piezoelectric sensing/harvesting in the airway, which we validated with a benchtop experiment. Our work offers a model-based roadmap for implantable SPD sensing solutions. We also use the model to theorize a new form of SPD sensing that can detect broadband flow information.
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