A microbubble pressure transducer with bubble nucleation core

A microchannel-based microbubble (μB) transducer (μBPT) having a μB nucleation core (μBNC) was developed to achieve low power operation in wet environments. In this work, we investigate μB dynamics within the transducer structure and pressure transduction. The transducer leverages electrochemical impedance (EI)-based measurement to monitor the instantaneous response of μB size changes induced by hydrostatic pressure changes. We demonstrated on-demand μB nucleation by electrolysis and real-time pressure tracking (-93 Ω/mmHg over 0-350 mmHg). Repeatable, efficient electrolytic generation of stable microbubbles (<; 1.5 nL with <; 2% size variation) was achieved using a μBNC structure attached centrally to the microchannel. Biocompatible construction (only Parylene and Pt), small footprint, low power consumption (<; 60 μW), and liquid-based operation of μBPTs are ideal for in vivo pressure monitoring applications.