High-Throughput Volumetric Photoacoustic Imaging of Living Vascularized Organoids

摘要 在过去的十年中，开发中的治疗化合物数量增加了62 癌症、糖尿病、神经退行性疾病和心血管疾病，总支出 几乎翻了一番。尽管投资巨大，但食品和药物管理局批准的新药平均数量 自20世纪90年代以来，美国食品药品监督管理局（FDA）已经下降，主要是由于人类临床试验的成功率低。 试验以及与候选药物相关的疗效不足和/或过度不良（毒性）反应。 用于药物测试的平面细胞培养物和动物模型通常不能准确地反映人体生理学和 病理基于三维（3D）人体细胞的器官芯片模型，结合先进的 血管化和微流体技术，已越来越多地用于改善药物测试， 概括了体内人类对应物的重要生理参数。但 用纯光学成像方法表征3D血管化类器官培养物具有挑战性， 仅小深度（~1 mm）和/或缺乏功能成像能力。所有类器官可达2-3 mm 尺寸，并且不同位置处的细胞对药物治疗的响应可能由于以下原因而显著不同： 不均匀的组织性质、有限的分子扩散和不均匀的血管分支。解决 这些问题，我们建议开发一种新的集成成像生物反应器平台，结合了小型化 光声断层扫描（mini-PAT）系统（Aim 1）和人血管化器官芯片生物反应器 (Aim 2）。Mini-PAT可以直接集成到生物反应器上，并提供关键的解剖和功能 关于3D类器官的发育、脉管系统功能和代谢的信息。作为概念的证明， 我们将应用集成平台进行芯片上、纵向和体积成像， 肝细胞癌（HCC）类器官，它们的多尺度血管化，以及它们对抗- 血管生成药物（Aim 3）。最重要的是，mini-PAT和生物反应器都是高度紧凑和低成本的 （每单位约200美元），因此它们可以很容易地多路复用，以并行监测大量类器官。的 因此，高度异质性的药物-类器官相互作用可以同时以统计学上有意义的方式进行研究。 方式最终，该提案将为各种应用程序提供平台技术， 在人体组织模型上进行高通量病理学测试。更令人兴奋的是，这将为 使用一系列源自患者的疾病模型进行个性化药物筛选。

Abstract Over the last decade, there has been a 62% rise in the number of therapeutic compounds under development for cancers, diabetes, neurodegenerative diseases, and cardiovascular diseases, and the total expenditure has nearly doubled. Despite the significant investment, the average number of new drugs approved by the Food and Drug Administration (FDA) has declined since the 1990s, mainly due to the low success rate of human clinical trials and the insufficient efficacy and/or excessive adverse (toxic) reactions associated with the candidate drugs. Planar cell cultures and animal models used in drug testing often fail to accurately reflect human physiology and pathology. Three-dimensional (3D) human cell-based organ-on-a-chip models, combined with advanced vascularization and microfluidics technologies, have been increasingly used to improve drug testing, by recapitulating important physiological parameters of their in vivo human counterparts. However, the characterization of 3D vascularized organoid cultures is challenging with pure optical imaging methods that reach only small depths (~1 mm) and/or lacks functional imaging capability. The organoids can reach 2–3 mm in all dimensions, and the response to the drug treatment by cells at different locations may significantly vary due to non-uniform tissue properties, limited molecular diffusion, and heterogeneous vascular arborization. To address these issues, we propose to develop a novel integrated imaging-bioreactor platform that combines a miniaturized photoacoustic tomography (mini-PAT) system (Aim 1) and a human vascularized organ-on-a-chip bioreactor (Aim 2). Mini-PAT can be directly integrated onto the bioreactor and provide critical anatomical and functional information about the 3D organoid’s development, vasculature function and metabolism. As proof of concept, we will apply the integrated platform for on-chip, longitudinal, and volumetric imaging of the progression of hepatocellular carcinoma (HCC) organoids, their multiscale vascularization, and their response to anti- angiogenic drugs (Aim 3). Most importantly, both the mini-PAT and bioreactor are highly compact and low-cost (~$200 per unit), so they can be readily multiplexed for monitoring a large array of organoids in parallel. The highly heterogeneous drug-organoid interactions can thus be simultaneously studied in a statistically meaningful manner. Ultimately, this proposal will provide a platform technology for a variety of applications that require high-throughput pathological testing on human tissue models. More excitingly, it would pave the way for personalized medicine screening using an array of patient-derived disease models.