IADR Abstract Archives
An Environment for Exposing Cells to Defined Doses of Ultrasound
Objectives: Several studies reporting the effects of ultrasound on cells have ill-defined ultrasound parameters due to usage of standard cell culture platforms causing standing waves and delivery of unknown dosage of ultrasound, unsuitable for development of bone healing strategies. Here we report development of a well-defined ultrasound exposure set up for controlled cell experiments in a cell culture cassette.
Methods: The acoustic pressure fields of in-house manufactured 25 and 45 kHz piezoelectric transducers (continuous wave) were analysed in a glass tank (60cm x 30cm x 30cm, filled with degassed water, lined with low frequency ultrasonic absorbers) using a 4mm diameter needle hydrophone. Transverse scans (8mm x 105mm, perpendicular scan of a beam profile) at 5mm and further two scans at 25mm distance with or without the insertion of cell culture cassette were analysed. Longitudinal scans (25mm x 85mm, in direction of wave propagation) at 5mm distance perpendicular to the transducer were analysed. The relationship between the driving current of the transducer and negative peak pressure values was assessed using point measurements.
Results: The transverse and longitudinal scans showed absence of standing waves and combined with the point peak pressure values there was no significant effect on ultrasound propagation due to insertion of a cassette(fig.1). Regression analysis confirmed a linear relationship between the driving current and the pressure generated in water (R2 values of 0.9937 and 0.9739 for 25 kHz and 45 kHz frequencies at 5mm distance) where the cells would be located during experimentation, and effects of varying pressure and intensity of ultrasound could be assessed more reliably.
Conclusions: An ultrasound exposure system has been developed that does not generate standing waves due to the presence of acoustic absorbers and allows delivery of known parameters of ultrasound to cells for experimentation for bone healing applications.
Methods: The acoustic pressure fields of in-house manufactured 25 and 45 kHz piezoelectric transducers (continuous wave) were analysed in a glass tank (60cm x 30cm x 30cm, filled with degassed water, lined with low frequency ultrasonic absorbers) using a 4mm diameter needle hydrophone. Transverse scans (8mm x 105mm, perpendicular scan of a beam profile) at 5mm and further two scans at 25mm distance with or without the insertion of cell culture cassette were analysed. Longitudinal scans (25mm x 85mm, in direction of wave propagation) at 5mm distance perpendicular to the transducer were analysed. The relationship between the driving current of the transducer and negative peak pressure values was assessed using point measurements.
Results: The transverse and longitudinal scans showed absence of standing waves and combined with the point peak pressure values there was no significant effect on ultrasound propagation due to insertion of a cassette(fig.1). Regression analysis confirmed a linear relationship between the driving current and the pressure generated in water (R2 values of 0.9937 and 0.9739 for 25 kHz and 45 kHz frequencies at 5mm distance) where the cells would be located during experimentation, and effects of varying pressure and intensity of ultrasound could be assessed more reliably.
Conclusions: An ultrasound exposure system has been developed that does not generate standing waves due to the presence of acoustic absorbers and allows delivery of known parameters of ultrasound to cells for experimentation for bone healing applications.
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