Hydrogels are formed using various triggers, including light irradiation, pH adjustment, heating, cooling, or chemical addition. Here, a new method for forming hydrogels is introduced: ultrasound-triggered enzymatic gelation. Specifically, ultrasound is used as a stimulus to liberate liposomal calcium ions, which then trigger the enzymatic activity of transglutaminase. The activated enzyme catalyzes the formation of fibrinogen hydrogels through covalent intermolecular crosslinking. The catalysis and gelation processes are monitored in real time and both the enzyme kinetics and final hydrogel properties are controlled by varying the initial ultrasound exposure time. This technology is extended to microbubble-liposome conjugates, which exhibit a stronger response to the applied acoustic field and are also used for ultrasound-triggered enzymatic hydrogelation. To the best of the knowledge, these results are the first instance in which ultrasound is used as a trigger for either enzyme catalysis or enzymatic hydrogelation. This approach is highly versatile and can be readily applied to different ion-dependent enzymes or gelation systems. Moreover, this work paves the way for the use of ultrasound as a remote trigger for in vivo hydrogelation.

中文翻译：

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超声波引发的酶促凝胶化。

水凝胶是通过各种触发因素形成的，包括光照射、pH 调节、加热、冷却或化学添加。这里介绍了一种形成水凝胶的新方法：超声触发酶促凝胶化。具体来说，超声波被用作释放脂质体钙离子的刺激，然后触发转谷氨酰胺酶的酶活性。活化的酶通过共价分子间交联催化纤维蛋白原水凝胶的形成。实时监测催化和凝胶化过程，并且通过改变初始超声暴露时间来控制酶动力学和最终水凝胶特性。该技术扩展到微泡-脂质体缀合物，其对所施加的声场表现出更强的响应，并且也用于超声触发的酶促水凝胶化。据了解，这些结果是首次使用超声波作为酶催化或酶水凝胶的触发剂。这种方法用途广泛，可以轻松应用于不同的离子依赖性酶或凝胶系统。此外，这项工作为使用超声波作为体内水凝胶的远程触发器铺平了道路。