RESUMEN
Nanodrum resonators have been fabricated using nanometer-thick gold films as the drumheads. The fabrication method is favorable for large-area array manufacture of arbitrary shapes. The drum resonators exhibit fundamental mode vibration frequencies in the MHz regime. We use the stretched-plate model to describe the natural vibrations of the drum. The Q factor of the fundamental mode increases as the thickness of the drum increases and decreases as the drum diameter goes up. The highest Q factor of the fundamental mode reaches 290 at room temperature and atmospheric pressure. Based on the deduced material properties we estimate that the resonator has a mass sensitivity of 1.11 × 10-22 g/Hz.
RESUMEN
Time-lapse mechanical properties of stem cell derived cardiac organoids are important biological cues for understanding contraction dynamics of human heart tissues, cardiovascular functions and diseases. However, it remains difficult to directly, instantaneously and accurately characterize such mechanical properties in real-time and in situ because cardiac organoids are topologically complex, three-dimensional soft tissues suspended in biological media, which creates a mismatch in mechanics and topology with state-of-the-art force sensors that are typically rigid, planar and bulky. Here, we present a soft resistive force-sensing diaphragm based on ultrasensitive resistive nanocracked platinum film, which can be integrated into an all-soft culture well via an oxygen plasma-enabled bonding process. We show that a reliable organoid-diaphragm contact can be established by an 'Atomic Force Microscope-like' engaging process. This allows for instantaneous detection of the organoids' minute contractile forces and beating patterns during electrical stimulation, resuscitation, drug dosing, tissue culture, and disease modelling.
