Controlled Cavitation for Ultrasound-Mediated Drug Delivery

9987698Prausnitz药物输送的最大挑战之一是将分子输送到体内的精确位置。 我们实验室和其他实验室的最新研究表明，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。 通过使用超声波瞬时破坏生物膜，化疗剂可以靶向肿瘤，从而减少癌症患者身体其他部位的副作用，并且胰岛素等药物可以通过皮肤输送，从而减少糖尿病患者忍受的针刺疼痛。该提案的重点是开发一种强大的方法来控制空化，从而控制其生物效应。 我们的方法是使用空化气泡发出的声谱（即声音）来表征空化，然后确定空化声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DU 145前列腺癌细胞的初步工作表明，在一半驱动频率下测量的压力（已知与稳定空化相关的信号）和频谱峰值之间的宽带噪声（已知与瞬态空化相关的信号）与在广泛的不同声学条件下测量的生物效应相关。 这验证了声谱中基于气穴的信号与生物效应相关的想法。 该提案提出的核心问题是，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，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临床。 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，我们将声谱特征与对药物递送有意义的两种生物效应相关联（分子摄取和细胞活力）在广泛的声学条件下（包括一系列频率）和广泛的环境条件（特别是不同数量和类型的空化核）。 然后，将这些数据与通过其他研究收集的其他数据相结合，我们将确定是否存在一个“普遍”的相关性，为所有研究的许多不同的实验条件。 我们的实验将使用DU 145前列腺癌细胞作为模型细胞系，钙黄绿素和德克萨斯红标记的牛血清白蛋白作为荧光模型药物，碘化丙啶作为活力染色剂。 定制设计的装置将在良好控制和表征的条件下应用超声，并允许准确收集声学光谱。 将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.