Experimental observations and numerical modeling of lipid-shell microbubbles with calcium-adhering moieties for minimally-invasive treatment of urinary stones

Pishchalnikov, Yuri A.; Behnke-Parks, William M.; Maeda, Kazuki; Colonius, Tim; Mellema, Matthew S.; Hopcroft, Matthew A.; Luong, A. Khai; Wiener, Scott; Stoller, Marshall L.; Kenny, Thomas W.; Laser, Daniel

doi:10.1121/2.0000958

Cited by 7 publications

(11 citation statements)

References 40 publications

(61 reference statements)

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“…The combination of HS-video microscopy and numerical modeling employed here showed a pronounced difference between the previously reported dynamics of initially spherical bubbles [22][23][24][25]27 and the dynamics of the SSA microbubbles at the surface of urinary stones. The SSA microbubbles expanded nonspherically (Mm.…”

Section: Discussioncontrasting

confidence: 60%

“…The system of equations (1) was solved with a twosubstep approach (section 1 of the Appendix) using adaptive time steps and an AMR algorithm (section 3 of the Appendix). In comparison with the numerical modeling in POMA, 27 the use of an improved system of equations (1) allows us to take into account expansion and compression of each phase in mixture regions. This improvement and the use of the AMR algorithm (section 3 of the Appendix) allowed us to increase the accuracy of the results, including the spatial and time resolution of gas-liquid interfaces and shock fronts.…”

Section: Resultsmentioning

confidence: 99%

“…8 in POMA. 27 Furthermore, whereas for the initially spherical bubbles the axial jet originated from the distal surface of the bubble, [22][23][24][25]27 the circumferential pinching of the SSA microbubble split the bubble into two parts producing two axial microjets directed away and toward the stone. The reentrant jet hitting the stone was either a single (P 01 , Mm.…”

Section: Discussionmentioning

confidence: 99%

“…In the present work, we used an AMR algorithm which showed greater peak pressures than the numerical simulations with a coarser grid. 27 The extent to which the coarseness of the grid affects pressure amplitudes was not investigated in this work. For these reasons, we believe that the present modeling results can provide only an order-ofmagnitude assessment of bubble-wall velocities and pressures generated during the collapse.…”

Section: Discussionmentioning

confidence: 99%

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High-speed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone

Pishchalnikov¹,

Behnke-Parks²,

Schmidmayer

et al. 2019

The Journal of the Acoustical Society of America

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Ultra-high-speed video microscopy and numerical modeling were used to assess the dynamics of microbubbles at the surface of urinary stones. Lipid-shell microbubbles designed to accumulate on stone surfaces were driven by bursts of ultrasound in the sub-MHz range with pressure amplitudes on the order of 1 MPa. Microbubbles were observed to undergo repeated cycles of expansion and violent collapse. At maximum expansion, the microbubbles' cross-section resembled an ellipse truncated by the stone. Approximating the bubble shape as an oblate spheroid, this study modeled the collapse by solving the multicomponent Euler equations with a two-dimensional-axisymmetric code with adaptive mesh refinement for fine resolution of the gas-liquid interface. Modeled bubble collapse and high-speed video microscopy showed a distinctive circumferential pinching during the collapse. In the numerical model, this pinching was associated with bidirectional microjetting normal to the rigid surface and toroidal collapse of the bubble. Modeled pressure spikes had amplitudes two-to-three orders of magnitude greater than that of the driving wave. Micro-computed tomography was used to study surface erosion and formation of microcracks from the action of microbubbles. This study suggests that engineered microbubbles enable stone-treatment modalities with driving pressures significantly lower than those required without the microbubbles.

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Section: Discussioncontrasting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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High-speed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone

Pishchalnikov¹,

Behnke-Parks²,

Schmidmayer

et al. 2019

The Journal of the Acoustical Society of America

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“…The bubbles are attracted to the stone surface, where the bubbles can then be manipulated and exploded using extracorporeal ultrasonic methods. 28 – 30…”

Section: Discussionmentioning

confidence: 99%

Dynamic properties of surfactant-enhanced laser-induced vapor bubbles for lithotripsy applications

et al. 2021

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Significance: Water is a primary absorber of infrared (IR) laser energy, and urinary stones are immersed in fluid in the urinary tract and irrigated with saline during IR laser lithotripsy. Laserinduced vapor bubbles, formed during lithotripsy, contribute to the stone ablation mechanism and stone retropulsion effects.Aim: Introduction of a surfactant may enable manipulation of vapor bubble dimensions and duration, potentially for more efficient laser lithotripsy.Approach: A surfactant with concentrations of 0%, 5%, and 10% was tested. A single pulse from a thulium fiber laser with wavelength of 1940 nm was delivered to the surfactant through a 200-μm-core optical fiber, using a wide range of laser parameters, including energies of 0.05 to 0.5 J and pulse durations of 250 to 2500 μs.Results: Bubble length, width, and duration with surfactant increased on average by 29%, 17%, and 120%, compared with water only.Conclusions: Our study demonstrated successful manipulation of laser-induced vapor bubble dimensions and duration using a biocompatible and commercially available surfactant. With further study, use of a surfactant may potentially improve the "popcorn" technique of laser lithotripsy within the confined space of the kidney, enable non-contact laser lithotripsy at longer working distances, and provide more efficient laser lithotripsy.

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Plasma formation in holmium:YAG laser lithotripsy

Pishchalnikov¹,

Behnke-Parks²,

Stoller

2023

Lasers Surg Med

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Objectives: During holmium:yttrium-aluminum-garnet (holmium:YAG) laser lithotripsy to break urinary stones, urologists frequently see flashes of light. As infrared laser pulses are invisible, what is the source of light? Here we studied the origin, characteristics, and some effects of flashes of light in laser lithotripsy. Methods: Ultrahigh-speed video-microscopy was used to record single laser pulses at 0.2-1.0 J energy lasered with 242 µm glass-core-diameter fibers in contact with whole surgically retrieved urinary stones and hydroxyapatite (HA)-coated glass slides in air and water. Acoustic transients were measured with a hydrophone. Visible-light and infrared photodetectors resolved temporal profiles of visiblelight emission and infrared-laser pulses. Results: Temporal profiles of laser pulses showed intensity spikes of various duration and amplitude. The pulses were seen to produce dim light and bright sparks with submicrosecond risetime. The spark produced by the intensity spike at the beginning of laser pulse generated a shock wave in the surrounding liquid. The subsequent sparks were in a vapor bubble and generated no shock waves. Sparks enhanced absorption of laser radiation, indicative of plasma formation and optical breakdown. The occurrence and number of sparks varied even with the same urinary stone. Sparks were consistently observed at laser energy >0.5 J with HA-coated glass slides. The slides broke or cracked by cavitation with sparks in 63 ± 15% of pulses (1.0 J, N = 60). No glass-slide breakage occurred without sparks (1.0 J, N = 500). Conclusion: Unappreciated in previous studies, plasma formation with freerunning long-pulse holmium:YAG lasers can be an additional physical mechanism of action in laser procedures.

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Experimental observations and numerical modeling of lipid-shell microbubbles with calcium-adhering moieties for minimally-invasive treatment of urinary stones

Cited by 7 publications

References 40 publications

High-speed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone

High-speed video microscopy and numerical modeling of bubble dynamics near a surface of urinary stone

Dynamic properties of surfactant-enhanced laser-induced vapor bubbles for lithotripsy applications

Plasma formation in holmium:YAG laser lithotripsy

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