Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl₂ solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), gas permeability and water contact angle measurements. Ultrasonic treatment aids the interactions between the calcium ions and silk molecular chains which leads to increased amounts of intermolecular β-sheets and α-helix. This unique structural change caused the silk film to be highly insoluble in water while also inducing a hydrophilic swelling property. The ultrasound-regulated silk materials also showed higher thermal stability, better biocompatibility and breathability, and favorable mechanical strength and flexibility. It was also possible to tune the enzymatic degradation rate and biological response (cell growth and proliferation) of protein materials by changing ultrasound parameters. This study provides a unique physical and non-contact material processing method for the wide applications of protein-based biomaterials.

超声因其效率高、操作简便、无需化学处理、重复性好、控制水平高等优点可应用于生物材料领域。在这项工作中，我们证明超声波能够在溶液组装阶段快速调节蛋白质结构，以获得基于蛋白质的材料的设计特性。溶解在甲酸-CaCl ₂溶液系统中的丝素蛋白在超声波中以不同的时间和功率进行处理。通过改变这些变量，可以对丝绸的物理性质和结构进行微调，并通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、差示扫描量热法（DSC）对结果进行研究）、热重分析（TGA）、动态力学分析（DMA）、透气性和水接触角测量。超声波处理有助于钙离子和丝分子链之间的相互作用，从而导致分子间β折叠和α螺旋数量增加。这种独特的结构变化导致丝膜高度不溶于水，同时还具有亲水溶胀特性。超声调节的丝材料还表现出更高的热稳定性、更好的生物相容性和透气性以及良好的机械强度和柔韧性。还可以通过改变超声参数来调节蛋白质材料的酶降解速率和生物反应（细胞生长和增殖）。该研究为蛋白质基生物材料的广泛应用提供了一种独特的物理、非接触式材料加工方法。