医用内窥式光致超声换能器研究

Compared with traditional piezoelectric ultrasound transducer, the optically-excited ultrasonic transducer is not only easier to realize miniaturization and array scale, but also it can produce more precision ultrasound with high intensity. Therefore, this kind of device is regarded as a promising candidate for endoscopic ultrasound imaging and therapy applications. Based on our previous work on optically-excited ultrasound materials, in this project, related researches on fundamental theoretical, experimental comparative analysis and integrated process will be conducted to enhance the performance of the device. In our plan, to improve the optic-ultrasound energy conversion coefficient of the inorganic/PDMS composite, the intrinsic properties and enhanced light absorptions of Carbon Nanofibers (CNF) and Black Phosphorus (BP) will be investigated; to increase the operational frequency of the endoscopic optically-excited transducer for ultrasound imaging, the influence of laser pulse width, heat conduction time, and thickness on the characterization of frequency response of the inorganic/PDMS composite will be analyzed; to enhance the acoustic pressure (negative pressure) of the endoscopic optically-excited transducer for ultrasound therapy, the inner link between the acoustic pressure and the composite’s thickness & transducer’s structure will be studied; Finally, the integrated optically-excited transducers for endoscopic ultrasound imaging and therapy of vulnerable plaque will be designed and fabricated. The success of this project will be of great significance for frontier scientific research on new-type ultrasound device and medical ultrasound technology.

同传统压电型超声换能器相比，光致超声换能器不仅更易小型化与阵列化，而且能产生更精准的高强声压，所以在内窥式超声诊断与治疗方面具有广阔的应用前景。本项目拟在前期工作基础之上，围绕光致超声材料，开展相关基础理论研究、实验对比分析和集成工艺探索，以提升光致超声换能器性能。主要研究内容包括：以碳纳米纤维和黑磷为研究对象，通过研究本征光声转换与增强型光吸收，以提高无机/有机复合材料的光声转化效率；通过研究激光脉宽、材料间热扩散时间和复合材料厚度对材料频率响应特性的影响，以提高用于内窥成像的光致超声换能器中心频率；通过研究复合材料厚度和声换能器结构与声压的内在联系，以提升用于介入式治疗的光致超声换能器声压/负压值；设计与研制出“面向血管内易损斑块诊疗一体化”的内窥式光致超声换能器。本项目的完成对新型声学器件和医学超声技术等前沿科学问题的深入研究有着重要的意义。

本项目通过本征光声转换研究与增强型光吸收研究，提高了无机/有机复合材料的光声转化效率；通过各项异性导热有机/无机复合结构构筑，实现了用于内窥成像的光致超声换能器中心频率提高；通过在器件结构中引入空气背衬和利用空气微腔改变几何聚焦曲率，实现了光致超声换能器的输出负压改善和动态聚焦；通过自修复光致超声换能器的研制和全光型超声成像系统的搭建，实现了光致聚焦超声溶栓和血管内光致超声成像，为诊疗一体化奠定了坚实的基础。项目研究的内容涉及声学、医学、光学、纳米材料等学科交叉，对于光声转化、血管内超声成像与治疗等前沿科学问题的深入研究具有重要的科学意义。本项目在Nature Communications、Nano Energy、Environment Energy Materials、Photoacoustics、IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,等国际权威期刊发表SCI学术论文12篇，其中两篇入选高被引论文和热点文章，获得授权中国发明专利3项。