Carbon Nanotubes and Polymer Based Pressure Micro-Sensor for Manometric Catheters

摘要

In this paper we investigate the fabrication process of a novel polymer based pressure micro-sensor for use inmanometric measurements in medical diagnostics. Review and analysis of polymer materials properties and polymerbased sensors has been carried out and has been reported by us elsewhere [1]. The interest in developing a novel polymerbased flexible pressure micro-sensor was motivated by the numerous problems inherent in the currently availablemanometric catheters used in the hospitals. The most critical issue regarding existing catheters was the running andmaintenance costs [2]. Thus expensive operation costs lead to reuse of the catheters, which increase the risk for diseasetransmission. The novel flexible polymer based pressure micro-sensor was build using SU-8, which is a special kind ofnegative photoresist. Single-walled carbon nanotubes (SWCNTs) and aluminum are used as the sensing material andcontacting electrodes respectively. The pressure sensor diaphragm was first patterned on top of an oxidized silicon waferusing SU-8, followed by aluminum deposition to define the electrodes. The carbon nanotube is then deposited usingdielectrophoresis (DEP) process. Once the carbon nanotubes are aligned in between these electrodes, the remaining ofthe sensor structure is formed using SU-8. Patterning of SU-8 and release from the substrate make the device ready forfurther testing of sensing ability. This research not only investigates the use of polymeric materials to build pressuresensors, but also explores the feasibility of full utilization of polymeric materials to replace conventional siliconmaterials in micro-sensors fabrication for use in medical environments. The completed sensor is expected to form anintegral part of a large versatile sensing system. For example, the biocompatible artificial skin, is predicted to be capableof sensing force, pressure, temperature, and humidity, and may be used in such applications as medical and roboticsystem.