Sonothrombolysis: Effect of 220kHz insonation scheme

Holland, Christy K.; Kleven, Robert T.; Karani, Kunal; Salido, Nuria González; Shekhar, Himanshu; Haworth, Kevin J.

doi:10.1016/j.ultrasmedbio.2019.07.537

Cited by 1 publication

(1 citation statement)

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“…A MB oscillator is an extremely complex system that has beneficial applications in a wide range of fields including material science and sonochemistry [64][65][66], food technology [67] underwater acoustics [68,69] and medical ultrasound (ranging from imaging blood vessels [70], drug delivery [50] to thrombolysis [71] and the treatment of brain through intact skull [48,72]). In addition to these important applications, the complex dynamical properties of the MB system make it a very interesting subject in the field of nonlinear dynamics.…”

Section: Discussionmentioning

confidence: 99%

Experimental and numerical evidence of intensified non-linearity at the micro and nano scale: The lipid coated acoustic bubble

Sojahrood,

Haghi,

Porter

et al. 2021

Preprint

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A lipid coated bubble (LCB) oscillator is a very interesting non-smooth oscillator with many important applications ranging from industry and chemistry to medicine. However, due to the complex behavior of the coating intermixed with the nonlinear behavior of the bubble itself, the dynamics of the LCB are not well understood. In this work, lipid coated Definity microbubbles (MBs) were sonicated with 25 MHz 30 cycle pulses with pressure amplitudes between 70kPa-300kPa. Here, we report higher order subharmonics in the scattered signals of single MBs at low amplitude high frequency ultrasound excitations. Experimental observations reveal the generation of period 2(P2), P3, and two different P4 oscillations at low excitation amplitude. Despite the reduced damping of the uncoated bubble system, such enhanced nonlinear oscillations has not been observed and can not be theoretically explained for the uncoated bubble. To investigate the mechanism of the enhanced nonlinearity, the bifurcation structure of the lipid coated MBs is studied for a wide range of MBs sizes and shell parameters. Consistent with the experimental results, we show that this unique oscillator can exhibit chaotic oscillations and higher order subharmonics at excitation amplitudes considerably below those predicted by the uncoated oscillator. Buckling or rupture of the shell and the dynamic variation of the shell elasticity causes the intensified non-linearity at low excitations. The simulated scattered pressure by single MBs are in good agreement with the experimental signals.

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