Liu Hang, Ding Shuchen, Lin Xinyi, Wang Suhao, Wang Yue, Feng Zhiyun, Song Jizhou
Department of Engineering Mechanics, Soft Matter Research Center, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, State Key Laboratory of Brain-Machine Intelligence, Zhejiang University, Hangzhou 310027, China.
Center of Orthopedics, The 903rd Hospital of People's Liberation Army, Hangzhou Zhejiang 310003, China.
ACS Nano. 2024 Jul 15. doi: 10.1021/acsnano.4c02426.
Ultrasound treatment has been recognized as an effective and noninvasive approach to promote fracture healing. However, traditional rigid ultrasound probe is bulky, requiring cumbersome manual operations and inducing unfavorable side effects when functioning, which precludes the wide application of ultrasound in bone fracture healing. Here, we report a stretchable ultrasound array for bone fracture healing, which features high-performance 1-3 piezoelectric composites as transducers, stretchable multilayered serpentine metal films in a bridge-island pattern as electrical interconnects, soft elastomeric membranes as encapsulations, and polydimethylsiloxane (PDMS) with low curing agent ratio as adhesive layers. The resulting ultrasound array offers the benefits of large stretchability for easy skin integration and effective affecting region for simple skin alignment with good electromechanical performance. Experimental investigations of the stretchable ultrasound array on the delayed union model in femoral shafts of rats show that the callus growth is more active in the second week of treatment and the fracture site is completely osseous healed in the sixth week of treatment. Various bone quality indicators (e.g., bone modulus, bone mineral density, bone tissue/total tissue volume, and trabecular bone thickness) could be enhanced with the intervention of a stretchable ultrasound array. Histological and immunohistochemical examinations indicate that ultrasound promotes osteoblast differentiation, bone formation, and remodeling by promoting the expression of osteopontin (OPN) and runt-related transcription factor 2 (RUNX2). This work provides an effective tool for bone fracture healing in a simple and convenient manner and creates engineering opportunities for applying ultrasound in medical applications.
超声治疗已被公认为促进骨折愈合的一种有效且无创的方法。然而，传统的刚性超声探头体积庞大，操作繁琐，且在工作时会产生不利的副作用，这限制了超声在骨折愈合中的广泛应用。在此，我们报道了一种用于骨折愈合的可拉伸超声阵列，其特征在于采用高性能的1-3型压电复合材料作为换能器，采用桥岛图案的可拉伸多层蛇形金属薄膜作为电互连，采用软弹性体膜作为封装，并采用低固化剂比例的聚二甲基硅氧烷（PDMS）作为粘合层。所得的超声阵列具有大拉伸性的优点，便于与皮肤整合，有效作用区域易于与皮肤对齐，且具有良好的机电性能。对大鼠股骨干延迟愈合模型上的可拉伸超声阵列进行的实验研究表明，在治疗的第二周骨痂生长更为活跃，在治疗的第六周骨折部位完全骨性愈合。通过可拉伸超声阵列的干预，可以提高各种骨质量指标（如骨模量、骨矿物质密度、骨组织/总组织体积和小梁骨厚度）。组织学和免疫组织化学检查表明，超声通过促进骨桥蛋白（OPN）和 runt 相关转录因子 2（RUNX2）的表达来促进成骨细胞分化、骨形成和重塑。这项工作以简单方便的方式为骨折愈合提供了一种有效的工具，并为超声在医学应用中的应用创造了工程机会。
