Medical catheters, which are widely used in medical treatment and biopsy, are slender and rod-shaped mainly for use in fine tubular tissues such as blood vessels and bronchi.However, when it is desired to impart various functions, a manufacturing method is adopted in which functions are integrated layer by layer.There has been a demand for a catheter manufacturing technique that achieves both multifunctionality and a practical size reduction that is compatible with the target body site, which is different from the conventional manufacturing method of multi-layer integration.

　Under these circumstances, this research focused on the hot drawing process, which is similar to the manufacturing method of "Kintaro-ame".It is also used in the manufacture of optical communication fibers. By heating and stretching a molded product with the required structure and function, it can be scaled down while maintaining its structure and function, and is as thin as a human hair. Fiber can be made.Furthermore, by introducing a shape memory alloy wire inside the fiber, we succeeded in fabricating a multifunctional catheter that has an actuator function for bending motion and an electrochemical sensing function for detecting neurotransmitters.

　Assuming that this catheter will be applied to blood vessels and bronchi, we tested the sensor function in an experimental system modeled on the bifurcation structure of blood vessels. It was confirmed that the measurement is possible.

　In this way, by discovering a technology that can integrate a variety of functions into fibers as thin as several hundred microns, actuators, chemical sensing, microchannels, optical paths, camera functions, etc. have all been integrated into practical applications. It is expected that the development of new multifunctional catheters with high performance will progress.

Paper information:[ACS Applied Engineering Materials] Shape-memory-alloys enabled actuatable fiber sensors via the preform-to-fiber fabrication