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以直径1μm的脂质体为空化研究对象,从修正的Rayleigh空化方程入手,研究机械系数(MI)对300 kHz和1 MHz超声作用时空化效应的影响。脂质体的药物释放以超声作用前后脂质体中钙黄绿素的荧光强度为量度。模拟结果表明:在微泡振荡过程中,由超声波驱动产生的负向最大泡壁运动速度促使微泡半径从最大快速减小接近于零,微泡积聚到最大能量。对于300 kHz和1 MHz的激励超声,存在一个拐点(MI)值,当MI小于接近0.4时,1 MHz微泡半径变化幅度强于300 kHz;当MI>0.4时,300 kHz微泡半径变化幅度强于1 MHz。这一结果预示在此范围内,300 kHz的药物释放效果好于1 MHz。本研究为超声空化效应研究及超声药物释放应用提供了理论依据。
Taking the 1 μm diameter liposome as the cavitation object, the modified Rayleigh cavitation equation was used to study the effect of the mechanical coefficient (MI) on the cavitation effect at 300 kHz and 1 MHz ultrasound. The drug release of liposomes is measured as the fluorescence intensity of calcein in liposomes before and after sonication. The simulation results show that in the process of microbubble oscillation, the maximum negative wall velocity caused by ultrasonic driving causes the radius of the microbubble to decrease rapidly from maximum to zero and the microbubbles accumulate to the maximum energy. For 300 kHz and 1 MHz excitation ultrasound, there is a value of inflexion point (MI). When MI is less than 0.4, the radius of 1 MHz microbubble changes more than 300 kHz. When MI> 0.4, the amplitude of 300 kHz microbubble radius variation Stronger than 1 MHz. This result indicates that within this range, the drug release at 300 kHz is better than 1 MHz. This study provides a theoretical basis for the study of ultrasonic cavitation effect and the application of ultrasonic drug release.