Controlled Cavitation for Ultrasound-Mediated Drug Delivery

9987698PrausnitzOne药物传递的最大挑战是将分子传递到体内的精确位置。我们实验室和其他实验室最近的研究表明，超声波可以暂时破坏生物膜，从而将蛋白质和DNA等大型化合物输送到细胞和组织中。通过使用超声波暂时破坏生物膜，化疗药物可以靶向肿瘤，从而减少癌症患者身体其他部位的副作用，胰岛素等药物可以通过皮肤传递，从而减少糖尿病患者忍受针刺的痛苦。本建议的重点是发展一种强有力的方法来控制空化，从而控制其生物效应。我们的方法是利用空化气泡发出的声学频谱（即声音）来表征空化，然后确定空化声学频谱特征与细胞生物效应之间的相关性。我们实验室使用牛红细胞和DU145前列腺癌细胞进行的初步工作表明，在一半驱动频率下测量的压力（已知与稳定空化有关的信号）和频谱峰之间的宽带噪声（已知与瞬态空化有关的信号）与在广泛的不同声学条件下测量的生物效应相关。这证实了声学频谱中基于空化的信号与生物效应相关的观点。本提案提出的中心问题是，在一定范围的实验条件下确定的这种相关性是否可以推广到包括更广泛的条件范围，从而可以作为一种普遍的相关性应用于任何物理场景，无论是在实验室还是在诊所。为了确定声谱特征与可用于实时反馈控制的生物效应之间是否存在普遍相关性，我们将在广泛的声学条件（包括频率范围）和广泛的环境条件（特别是不同数量和类型的空化核）下，将声谱特征与两种对药物递送（分子摄取和细胞活力）具有重要意义的生物效应相关联。然后，将这些数据与通过其他研究收集的其他数据相结合，我们将确定所有研究的许多不同实验条件是否存在“普遍”相关性。我们的实验将以DU145前列腺癌细胞为模型细胞系，钙黄蛋白和德州红标记牛血清白蛋白为荧光模型药物，碘化丙啶为活力染色剂。定制设计的仪器将在良好的控制和表征条件下应用超声波，并允许准确收集声学光谱。使用流式细胞术进行分析。

9987698PrausnitzOne of the greatest challenges in drug delivery is the delivery of molecules to precise locations in the body. Recent studies in our laboratory and in the laboratories of others have shown that ultrasound can temporarily disrupt biological membranes, thereby delivering large compounds such as proteins and DNA into cells and across tissues. By transiently disrupting biological membranes using ultrasound, chemotherapuetic agents could be targeted to tumors thereby reducing side effects elsewhere in the body of cancer patients and drugs like insulin could be delivered across the skin and thereby reduce the pain of needle-sticks endured by diabetics. The focus of this proposal is to develop a robust method to control cavitation and thereby control its bioeffects. Our approach is to use the acoustic spectrum (i.e. sounds) given off by cavitation bubbles to characterize the cavitation and then identify correlations between features of the cavitational acoustic spectrum and bioeffects on cells. Preliminary work in our lab using bovine red blood cells and DU145 prostate cancer cells have shown that both the pressure measured at one-half the driving frequency (a signal known to be associated with stable cavitation) and the broadband noise between peaks in the spectrum (a signal know to be associated with transient cavitation) correlate with measured bioeffects over a wide range of different acoustic conditions. This validates the idea that cavitation-based signals in the acoustic spectrum correlate with bioeffects. The central question posed in this proposal asks whether this correlation identified over a certain range of experimental conditions can be generalized to include a much broader range of conditions and thereby might serve as a universal correlation to apply in any physical scenario, whether in the laboratory or the clinic. To determine if there is a universal correlation between features of the acoustic spectrum and bioeffects which can be used for real-time feedback control, we will correlate features of the acoustic spectrum with two bioeffects of significance for drug delivery (molecular uptake and cell viability) over a broad range of acoustic conditions (including a range of frequencies) and a broad range of environmental conditions (notably, different numbers and types of cavitation nuclei). Then, using this data in combination with other data collected through other studies, we will determine if there is a "universal" correlation for all the many different experimental conditions studied. Our experiments will use DU145 prostate cancer cells as a model cell line, calcein and Texas Red-labeled bovine serum albumin as fluorescent model drugs, and propidium iodide as a viability stain. A custom-designed apparatus will apply ultrasound under well controlled and characterized conditions and permit accurate collection of acoustic spectra. Analysis will be done using flow cytometry.