刺激離體細胞用低強度脈衝超音波實驗平台之開發

Development of a Low-Intensity Pulsed Ultrasound Experimental Platform for Stimulation of In Vitro Cells

黃鈺媞(Yu-Ti Huang)

指導教授 ： 胡威志 ； 陳景欣

中原大學/工學院/生物醫學工程研究所/碩士(2020年)

https://doi.org/10.6840/cycu202000720

摘要

本研究主要解決低強度脈衝超音波 (low-intensity pulsed ultrasound , LIPUS)刺激離體細胞的實驗技術上所存在的三個主要問題:一是調整超音波換能器相對放置位置，以降低細胞汙染的風險；二是解決超音波傳遞路徑中，因為傳遞介質的設計不佳和/或嚴重的聲能衰減；三是提供一均質聲壓場以解決培養皿上的細胞承受不均的超音波壓力場作用。就此精準量化超音波參數與提升LIPUS與細胞反應之間的對應關係。
因此，本研究開發一套專用於刺激離體細胞之LIPUS實驗平台，以期降低細胞汙染機率、減少駐波發生與聲能衰減，並產出均質之聲壓場。平台系統中，平面超音波換能器的規格與參數為孔徑5 cm之圓盤壓電晶片、中心頻率為1 MHz、脈衝重複頻率為200 Hz，工作週期為10%。
水中聲場測試結果顯示，超音波換能器能夠在距離換能器表面7 cm處產生均質的聲壓場，此均質聲壓場定義為聲壓峰值 - 3 dB面積，其面積大小為13.44 cm2 ，將細胞培養皿製成密封式細胞培養皿以避免換能器直接接觸培養基造成細胞汙染，穿過培養皿後的均質聲場為7.16 cm2 ，且聲壓衰減1.57 dB，再者，細胞存活率為99.98±0.04%，細胞死亡率為1.84±0.16%。本研究所開發的LIPUS實驗平台能夠提供刺激離體細胞之均質聲壓且具備低汙染風險。

關鍵字

低強度脈衝超音波 ； 離體細胞 ； 3T3-L1 ； 生物效應

並列摘要

This research solves three major problems in the experimental technology of low-intensity pulsed ultrasound (LIPUS) stimulation of in vitro cells. The first one is the reducing risk of cell contamination while adjust the relative position of the ultrasound transducer, the second one is solving the attenuation of acoustic energy due to the poor transmission medium as part of ultrasonic transmission path, and, the third is providing the homogeneous ultrasonic pressure field affect cells on the culture medium. In these ways, we could be quantifying the correspondence between ultrasonic parameters and cells response accurately.
Thus, we develop a LIPUS experimental platform to stimulate in vitro cells in this research to reduce the contamination of cells, the occurrence of standing waves and the attenuation of acoustic energy, and also produce a homogeneous ultrasonic pressure field for cells. In our experimental platform, we have a planar ultrasonic transducer with 5-cm diameter disc piezoelectric, 1-MHz center frequency, 200 Hz pulse repetition frequency (PRF) and 10% duty cycle.
The test result of the underwater sound field shows that the planar ultrasonic transducer can generate a homogeneous sound pressure field at a distance of 7-cm from the surface of transducer. This homogeneous sound pressure field is defined as the -3dB area of the sound pressure peak, and its area is 13.44 cm2. Then we seal the culture medium to prevent cell contamination from directly contacting of transducer. The homogeneous sound pressure field after passing through the culture medium is 7.16 cm2 , and the sound pressure is attenuated 1.57dB. Furthermore, the cell survival rate is 99.98±0.04%, and the cell death rate is 1.84±0.16%. The LIPUS experimental platform we develop in this research can provide a homogeneous sound pressure that stimulates in vitro cells and reduce the risk of contamination.

並列關鍵字

low-intensity pulsed ultrasound ； in vitro cells ； 3T3-L1 ； biological effects

參考文獻

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