低强度超声促进关节软骨修复的物理机制及优化研究

It has been demonstrated that low intensity ultrasound is beneficial to promoting articular cartilage repair. How to effectively guide and control treatment behavior is in high demand in order to get the best clinical treatment result. The project is aimed to clarify the physical mechanism of ultrasound promoting articular cartilage's repair, and quantitative control of dynamical behavior under the effect of ultrasound. We will study the mechanism of stable cavitation in repairing articular cartilage, establish an experimental system of ultrasound sterile exposure and passive cavitation detection, investigate the relation between stable cavitation and chondrocyte bioeffect. Furthermore, we will theoretically and experimentally investigate the exact mechanism of acoustic streaming in ultrasound promoting cartilage repair. We will develop a theoretical model for acoustic streaming considering the interaction of heat conduction and cavitation nuclei, investigate the quantitative control of acoustic streaming field under ultrasonic exposure. For examining the theoretical analysis, we will measure the acoustic streaming field and the induced shear force based on the microscale PIV measuring system, discuss the effect of ultrasonic parameters on acoustic streaming velocity and structure, and improve further the theoretical model. The project will further promote the application of low intensity ultrasound in clinical treatment of osteoarthritis.

低强度超声有利于促进关节软骨修复，有效地对治疗行为进行指导与控制是获得优化的临床效果的关键。本项目旨在明确超声促进关节软骨修复的物理机制，并定量调控超声作用下的动力学行为。我们拟研究超声稳态空化效应在关节软骨修复中的作用机理，建立并实现体外兔软骨细胞超声无菌照射及被动空化检测实验系统，探讨稳态空化与软骨细胞生物效应的关系。我们还将理论及实验研究声流在超声促进软骨修复作用中的确切机制，一方面基于已有的声流理论模型，考虑超声在流体中传播时的热传导、空化核之间的相互作用，建立超声激励下的声流场理论模型，探讨声流场结构的超声调控；另一方面基于微尺度粒子速度成像系统，定量测量声流场及其产生的剪切力场，研究不同超声参数作用下声流流速及结构对软骨细胞及组织的影响，并进一步完善理论模型。本项目的研究将进一步促进低强度超声在骨关节炎临床治疗中的应用。

本项目按计划研究超声促进关节软骨修复及治疗中的超声生物效应，开展的工作包括：(1) 采用时域-频域混合法建立了冲击波形成的数值计算模型，进一步提出实验测量与理论计算相结合方式定征大张角强聚焦换能器非线性声场。(2) 建立了球形共振腔聚焦换能器实现亚波长聚焦，并建立了非线性声场计算模型。提出一种多通道的声学结构，实现超声平面波的亚波长聚焦。(3) 研究了藻酸钙三维支架材料的力学特性与氯化钙/藻酸钠的配比的关系，并提出采用低强度脉冲超声处理藻酸钙凝胶，基于超声空化效应增强藻酸钙凝胶孔隙率的新方法。.本项目共发表SCI论文4篇，EI论文2篇，申请发明专利1项。在项目的支持下，共有3名博士及3名硕士研究生从事该方向的研究，其中4名已毕业，2人获博士学位，2人获硕士学位。在本项目资助下，参加国际学术会议1人次。