The real-time, in situ monitoring of calcium oxalate and brushite precipitation using magnetoelastic sensors

Abstract Reactions resulting in the precipitation of calcium oxalate, and brushite formation were monitored in situ using magnetoelastic sensors. These salts frequently occur in pathological precipitation in higher mammals. Calcium oxalate hydrates and brushite were formed by mixing anionic and cationic reactant solutions, with the resulting precipitation reaction starting immediately and mass loading the sensor. Magnetoelastic sensors operate on a remote query basis, using magnetic field telemetry, enabling the wireless, passive in situ sensors to be monitored from within opaque reaction chambers. The mass-sensitivity of the 17 mm × 6 mm × 28 μm sensor was found equal to −1.38 kHz/mg, suggesting applicability of the sensor for the real-time, in situ investigation of the nucleation and crystal growth kinetics of sparingly soluble salts.