Institute of Robotics and Intelligent Systems, ETH Zürich, Tannenstrasse 3, Zurich, CH-8092, Switzerland.
Department of Chemistry, Materials and Chemical Engineering, Politecnico di Milano, Milan, 20131, Italy.
Adv Sci (Weinh). 2022 Jan;9(1):e2103277. doi: 10.1002/advs.202103277. Epub 2021 Oct 31.
Variable stiffness catheters are typically composed of an encapsulated core. The core is usually composed of a low melting point alloy (LMPA) or a thermoplastic polymer (TP). In both cases, there is a need to encapsulate the core with an elastic material. This imposes a limit to the volume of variable stiffness (VS) material and limits miniaturization. This paper proposes a new approach that relies on the use of thermosetting materials. The variable stiffness catheter (VSC) proposed in this work eliminates the necessity for an encapsulation layer and is made of a unique biocompatible thermoset polymer with an embedded heating system. This significantly reduces the final diameter, improves manufacturability, and increases safety in the event of complications. The device can be scaled to sub-millimeter dimensions, while maintaining a high stiffness change. In addition, integration into a magnetic actuation system allows for precise actuation of one or multiple tools.
变刚度导管通常由封装的芯体组成。该芯体通常由低熔点合金（LMPA）或热塑性聚合物（TP）组成。在这两种情况下，都需要用弹性材料对芯体进行封装。这就对变刚度（VS）材料的体积施加了限制，限制了其微型化。本文提出了一种新的方法，依赖于使用热固性材料。本工作中提出的变刚度导管（VSC）不需要封装层，而是由一种独特的、具有嵌入式加热系统的生物相容性热固性聚合物制成。这显著减小了最终直径，提高了制造的可行性，并在发生并发症时增加了安全性。该设备可以缩小到亚毫米尺寸，同时保持高的刚度变化。此外，集成到磁致动系统中可以实现一个或多个工具的精确致动。
