细胞外基质的物理特性对超声导入技术发生机理及效果的影响

As a non-invasive, safe and targeted intracellular delivery technique, ultrasound and microbubble mediated drug and gene delivery has shown great potential for clinical applications. However, the relatively low delivery efficiency, and relatively low controllability of the outcomes, currently hinder its development and clinical translation. This is mainly due to the insufficient understanding of the underlying mechanisms and the dynamic process, especially at in vivo microenvironment...In this study, we propose to integrate the physiological and pathological relevant extracellular matrix properties into the mechanistic studies for ultrasound and microbubble mediated drug and gene delivery technique. By using advanced micro/nano fabrication techniques, we will fabricate the artificial biocompatible extracellular matrix with preciously defined physical properties, which match in vivo tissue (such as brain, cardiomyocyte, and bone) properties, and the relevant disease conditions (such as cancers). Experimental observations, and theoretical mathematic modelings and numerical simulations, will be deeply combined. By applying multiply methods, we will investigate the influence of the physical properties of extracellular matrix to the ultrasound and microbubble mediated drug and gene delivery technique, from the mechanisms to the outcomes. ..It has been demonstrated lately that the physical properties of extracellular matrix play an important role in regulating the physical properties, gene expression profile, functions and fate of the cells. Therefore, in this proposed study, we are expecting to obtain a series of groundbreaking new findings, thoroughly renew our understanding of this technique, and further promote the upgrading and clinic translation of this technique.

超声和微泡介导的药物和基因导入技术，是一项非侵入式的、安全性高的靶向给药技术，临床应用前景广泛。然而目前该技术的导入效率相对较低，导入效果的可控性相对较差。这主要是由于对其在细胞水平，特别是在体内环境中的，发生机理，认识尚不充分。本项目创新性地将仿生条件下的细胞外基质（简称“基质”），引入到超声导入技术的机理性研究中。利用先进的微纳制造技术，实现对基质物理特性的精准定义，使其符合体内不同组织（如脑、心肌、骨骼）、不同病理条件下（如癌变）的基质的物理特性。采取实验观测与理论研究高度结合的整体研究思路，综合运用多种研究方法，深刻揭示基质的物理特性对超声导入技术发生机理和效果的影响。细胞外基质的物理特性对细胞的物理特性、基因表达、功能和命运具有重要的调控作用。因此本项目的开展极有可能获得一系列突破性的研究成果，全面更新我们对超声导入技术发生机理的认知，推动该技术的革新和临床转化。

超声和微泡介导的药物和基因导入技术，是一项非侵入式的、安全性高的靶向给药技术，临床应用前景广泛。然而目前对技术的发生机理，特别是在（近）体内环境中的发生机理，认识尚不充分。以往研究中用于细胞培养的培养皿或玻璃基底比体内组织的硬度高出6-7个数量级。本项目将生理相关的细胞外基质的硬度，引入到超声导入技术的机理性研究中。我们使用水凝胶制备了硬度模拟软、硬组织的基质，在其上培养细胞，开展了实验和理论研究。结果显示基质的硬度对靶向微泡在细胞膜上的附着状态、微泡的声学动态响应和导入效果均有显著影响。我们利用PDMS弹性微柱阵列（其硬度为正常生理组织的硬度）测量了单细胞的细胞骨架收缩力。我们开发了高速相机记录微柱阵列明场图像结合记波图的图像分析法，以Khz的高时间分辨率揭示出在超声作用后存活细胞和永久受损细胞出现了完全不同的细胞骨架收缩力的响应：立即同时松弛，以及细胞内的逐渐发生的松弛波。我们建立了基于分子动力学的数学模型，探索了超声和靶向微泡作用后（发生声孔效应和无声孔效应发生两种情况下）细胞骨架收缩力响应的分子动力学机制，以及基质硬度对响应的影响，仿真计算结果与实验观测高度吻合。