Department of Mechanical Engineering, University of Minnesota, Minneapolis, USA.
Department of Urology, University of Minnesota, Minneapolis, MN, 55455, USA.
Ann Biomed Eng. 2021 Jan;49(1):149-161. doi: 10.1007/s10439-020-02528-7. Epub 2020 May 6.
This paper develops a novel instrumented urethral catheter with an array of force sensors for measuring the distributed pressure in a human urethra. The catheter and integrated portions of the force sensors are fabricated by the use of 3D printing using a combination of both soft and hard polymer substrates. Other portions of the force sensors consisting of electrodes and electrolytes are fabricated separately and assembled on top of the 3D-printed catheter to create a soft flexible device. The force sensors use a novel supercapacitive (iontronic) sensing mechanism in which the contact area between a pair of electrodes and a paper-based electrolyte changes in response to force. This provides a highly sensitive measure of force that is immune to parasitic noise from liquids. The developed catheter is tested using a force calibration test rig, a cuff-based pressure application device, an extracted bladder and urethra from a sheep and by dipping inside a beaker of water. The force sensors are found to have a sensitivity of 30-50 nF/N, which is 1000 times larger than that of traditional capacitive force sensors. They exhibit negligible capacitance change when dipped completely in water. The pressure cuff tests and the extracted sheep tissue tests also verify the ability of the sensor array to work reliably in providing distributed force measurements. The developed catheter could help diagnose ailments related to urinary incontinence and inadequate urethral closure pressure.
本文开发了一种新颖的带力传感器阵列的仪器化尿道导管，用于测量人体尿道中的分布式压力。导管和力传感器的集成部分是通过使用 3D 打印技术制造的，该技术结合了软聚合物和硬聚合物基底。力传感器的其他部分由电极和电解质组成，单独制造并组装在 3D 打印导管的顶部，形成一个柔软灵活的装置。力传感器采用一种新颖的超级电容（离子电子）传感机制，其中一对电极和纸质电解质之间的接触面积会响应力而发生变化。这提供了一种对力的高度敏感的测量方法，不受液体寄生噪声的影响。开发的导管通过力校准测试台、基于袖带的压力施加装置、从绵羊中提取的膀胱和尿道以及浸入烧杯中的水进行了测试。发现力传感器的灵敏度为 30-50 nF/N，比传统的电容式力传感器大 1000 倍。当完全浸入水中时，它们的电容变化可忽略不计。压力袖带测试和提取的绵羊组织测试也验证了传感器阵列在提供分布式力测量方面可靠工作的能力。开发的导管可帮助诊断与尿失禁和尿道闭合压不足相关的疾病。
