The Vibration Behavior of Sub‐Micrometer Gas Vesicles in Response to Acoustic Excitation Determined via Laser Doppler Vibrometry

The ability to monitor sub‐micrometer gas vesicles' (GVs) vibration behavior to nonlinear buckling and collapse using laser Doppler vibrometry is reported, providing a precise noncontact technique for monitoring the motion of sub‐micrometer objects. The fundamental and first harmonic resonance frequencies of the vesicles are found to be 1.024 and 1.710 GHz, respectively. An interparticle resonance is furthermore identified at ≈300 MHz, inversely dependent upon the agglomerated GV size of around 615 nm. Most importantly, the vesicles amplify and broaden input acoustic signals at far lower frequencies—for example, 7 MHz—associated with medical and industrial applications, and they are found to transition from a linear to nonlinear response at 150 kPa and to collapse at 350 kPa or greater. Produced by microbes, sub‐micrometer gas vesicles are stable and small enough to pass the blood–brain barrier, providing novel ultrasound imaging and medical treatment options. However, little is known about their resonance, buckling, and collapse—until now. Using laser Doppler interferometry, a fundamental resonance is found at 1.024 GHz and buckling to collapse at 350 kPa from 7 MHz ultrasound.