The Destruction of Escherichia Coli Biofilms Using High-Intensity Focused Ultrasound

Bigelow, Timothy A.; Northagen, Trevor; Hill, Thomas M.; Sailer, Frances C.

doi:10.1016/j.ultrasmedbio.2008.12.001

Cited by 62 publications

(52 citation statements)

References 24 publications

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“…The coefficient of reflection for graphite was measured to be .65 in our preliminary study. The pressure of 13 MPa guarantees the ability of histotripsy to kill bacteria as indicated by Bigelow et al [4].…”

Section: Ultrasound Exposurementioning

confidence: 99%

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Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

Bigelow

Halverson

et al. 2012

AIP Conference Proceedings

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Medical implants are prone to colonization by bacterial biofilms, which are highly resistant to antibiotics. Normally, surgery is required to replace the infected implant. One promising non-invasive treatment option is to destroy the biofilm with high-intensity focused ultrasound (HIFU) exposure. In our study, Pseudomonas aeruginosa bacterial biofilms were grown on graphite disks in a flow chamber for three days prior to exposing them to ultrasound pulses of varying duration or burst period. The pulses were 20 cycles in duration at a frequency of 1.1 MHz from a spherically focused transducer (f/1, 63 mm focal length), creating peak compressional and rarefactional pressures at the disk surface of 30 and 13 MPa, respectively. P. aeruginosa were tagged with GFP and cells killed by HIFU were visualized using propidium iodide, which permeates membranes of dead cells, to aid determining the extent of biofilm destruction and whether cells are alive or dead. Our results indicate that a 30-s exposure and 6-ms pulse period or those combinations with the same number of pulses, were sufficient to destroy the biofilm and to kill the remaining cells. Reducing the number of pulses decreased biofilm destruction, leaving more dead and live bacteria on the surface. Abstract. Medical implants are prone to colonization by bacterial biofilms, which are highly resistant to antibiotics. Normally, surgery is required to replace the infected implant. One promising non-invasive treatment option is to destroy the biofilm with high-intensity focused ultrasound (HIFU) exposure. In our study, Pseudomonas aeruginosa bacterial biofilms were grown on graphite disks in a flow chamber for three days prior to exposing them to ultrasound pulses of varying duration or burst period. The pulses were 20 cycles in duration at a frequency of 1.1 MHz from a spherically focused transducer (f/1, 63 mm focal length), creating peak compressional and rarefactional pressures at the disk surface of 30 and 13 MPa, respectively. P. aeruginosa were tagged with GFP and cells killed by HIFU were visualized using propidium iodide, which permeates membranes of dead cells, to aid determining the extent of biofilm destruction and whether cells are alive or dead. Our results indicate that a 30-s exposure and 6-ms pulse period or those combinations with the same number of pulses, were sufficient to destroy the biofilm and to kill the remaining cells. Reducing the number of pulses decreased biofilm destruction, leaving more dead and live bacteria on the surface.

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Section: Ultrasound Exposurementioning

confidence: 99%

“…Bigelow et al [4] verified the ability of high intensity focused ultrasound (HIFU) to mechanically destroy Escherichia coli (E. coli) biofilms. In their study, peak rarefactional pressure was varied to test the effect of power level on bacteria viability.…”

Section: Introductionmentioning

confidence: 99%

Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

Bigelow

Halverson

et al. 2012

AIP Conference Proceedings

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“…The combined use of therapeutic ultrasound with antibiotics usually decreases bacterial viability in vitro and in vivo [106]. On the other hand, sonication at high frequency is unable to kill bacteria, though some damage to the surrounding tissue is produced [107].…”

Section: Mechanical Action On Biostructuresmentioning

confidence: 99%

Interplay Between Mechanochemistry and Sonochemistry

Cintas

Cravotto

Barge

et al. 2014

Topics in Current Chemistry

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“…Also, histotripsy is compatible with traditional ultrasound imaging and enables therapy to be monitored in real-time (Rabkin et al, 2005;Parsons et al, 2006), since temperature regulation is not as stringent in heating-based HIFU modality. Moreover, histotripsy is safe because of the narrow beam width in the focal plane (on the order of mm for the À3 dB zone which corresponds to larger than 50% peak intensity), and because of the sharply defined pressure threshold for bubble cloud generation in cavitation histotripsy (Bigelow et al, 2009;Gateau et al, 2011) or for tissue boiling within the acoustic burst in boiling histotripsy (Canney et al, 2010). Therefore, the damage is highly likely to remain at the targeted region.…”

Section: Introductionmentioning

confidence: 99%

Dependence of ablative ability of high-intensity focused ultrasound cavitation-based histotripsy on mechanical properties of agar

Bigelow

Davis

et al. 2014

The Journal of the Acoustical Society of America

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Cavitation-based histotripsy uses high-intensity focused ultrasound at low duty factor to create bubble clouds inside tissue to liquefy a region, and provides better fidelity to planned lesion coordinates and the ability to perform real-time monitoring. The goal of this study was to identify the most important mechanical properties for predicting lesion dimensions, among these three: Young's modulus, bending strength, and fracture toughness. Lesions were generated inside tissue-mimicking agar, and correlations were examined between the mechanical properties and the lesion dimensions, quantified by lesion volume and by the width and length of the equivalent bubble cluster. Histotripsy was applied to agar samples with varied properties. A cuboid of 4.5mm width (lateral to focal plane) and 6mm depth (along beam axis) was scanned in a raster pattern with respective step sizes of 0.75 and 3mm. The exposure at each treatment location was either 15, 30, or 60s. Results showed that only Young's modulus influenced histotripsy's ablative ability and was significantly correlated with lesion volume and bubble cluster dimensions. The other two properties had negligible effects on lesion formation. Also, exposure time differentially affected the width and depth of the bubble cluster volume. KeywordsMechanical Engineering, algae, bending strength, cavitation, elastic moduli, fracture, polysaccharides, tissue, ultrasonics, bubble clusters, high intensity focused ultrasound, lesion formation, real time monitoring, Young's Modulus, biomechanics Disciplines Electrical and Computer Engineering | Mechanical Engineering CommentsThe following article appeared in Journal of the Acoustical Society of America 136 (2014) Cavitation-based histotripsy uses high-intensity focused ultrasound at low duty factor to create bubble clouds inside tissue to liquefy a region, and provides better fidelity to planned lesion coordinates and the ability to perform real-time monitoring. The goal of this study was to identify the most important mechanical properties for predicting lesion dimensions, among these three: Young's modulus, bending strength, and fracture toughness. Lesions were generated inside tissue-mimicking agar, and correlations were examined between the mechanical properties and the lesion dimensions, quantified by lesion volume and by the width and length of the equivalent bubble cluster. Histotripsy was applied to agar samples with varied properties. A cuboid of 4.5 mm width (lateral to focal plane) and 6 mm depth (along beam axis) was scanned in a raster pattern with respective step sizes of 0.75 and 3 mm. The exposure at each treatment location was either 15, 30, or 60 s. Results showed that only Young's modulus influenced histotripsy's ablative ability and was significantly correlated with lesion volume and bubble cluster dimensions. The other two properties had negligible effects on lesion formation. Also, exposure time differentially affected the width and depth of the bubble cluster volume.

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The Destruction of Escherichia Coli Biofilms Using High-Intensity Focused Ultrasound

Cited by 62 publications

References 24 publications

Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

Mechanical destruction of pseudomonas aeruginosa biofilms by ultrasound exposure

Interplay Between Mechanochemistry and Sonochemistry

Dependence of ablative ability of high-intensity focused ultrasound cavitation-based histotripsy on mechanical properties of agar

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