Miniaturized Flexible Piezoresistive Pressure Sensors: Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Copolymers Blended with Graphene Oxide for Biomedical Applications

Abstract

Piezoresistive pressure sensors have garnered significant attention because of their wide applications in automobiles, intelligent buildings, and biomedicine. For in vivo testing, the size of pressure sensors is a vital factor to monitor the pressure of specific portions of a human body. Therefore, the primary focus of this study is to miniaturize piezoresistive pressure sensors with graphene oxide (GO)-incorporated poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) composite films on a flexible substrate for biomedical applications. Prior to the fabrication of pressure sensors, a comprehensive material analysis was applied to identify the horizontal placement of GO flakes within the PEDOT:PSS copolymers, revealing a reduction in variable range hopping distance and an enhancement in carrier mobility. For devices scaled to 0.2 cm, the sensitivity of PEDOT:PSS pressure sensors was conspicuously decreased owing to the late response, which can be effectively solved by GO incorporation. Using technology computer-aided design simulations, the current crowded at the PEDOT:PSS film surface and in the vicinity of an indium–tin–oxide electrode corner was found to be responsible for the changes in piezoresistive behaviors of the scaled devices. The miniaturized flexible piezoresistive pressure sensors with PEDOT:PSS/GO composite films are capable of monitoring the brain pressure of intracranial surgery of a rat and discerning different styles of music for a potential application in hearing aids.

Recent Advances in Flexible Sensors and Their Applications

“…The flexible sensors with high sensitivity would play a promising role in weak signal monitoring, and also has future prospect in the medical field. Jer-Chyi Wang et al fabricated flexible pressure sensor composite film [119]. During intracranial surgery, this miniaturized pressure sensor could rapidly monitor the pressure of a rat's brain by the implantation of a sensor in the rat skull.…”

Real-Time Intraoperative Pressure Monitoring to Avoid Surgically Induced Localized Brain Injury Using a Miniaturized Piezoresistive Pressure Sensor

“…After that, part A and part B were combined and packaged together to form a sandwich structure of the pressure sensing device. For the detailed device fabrication method, we refer to our previous work, where we have introduced device miniaturization for pressure sensors . The schematic diagram of the fabricated pressure sensor with the sandwich structure is shown in Figure a.…”

“…A composite film of poly­(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) doped with graphene oxide (GO) has been used as a sensing material for this study. PEDOT:PSS is an excellent candidate for pressure sensing applications − because of its high electrochemical and thermal stability, high conductivity, favorable optical properties, and high transparency. , GO was doped into PEDOT:PSS to enhance the pressure sensing characteristics of the miniaturized piezoresistive pressure sensor as reported in our previous study . A flexible polyethylene terephthalate (PET) substrate coated with indium tin oxide (ITO) was used to fabricate the device using an interdigitated electrode (IDE) structure.…”

“…51,52 GO was doped into PEDOT:PSS to enhance the pressure sensing characteristics of the miniaturized piezoresistive pressure sensor as reported in our previous study. 53 A flexible polyethylene terephthalate (PET) substrate coated with indium tin oxide (ITO) was used to fabricate the device using an interdigitated electrode (IDE) structure. IDE structures, with feature size in the nanometer scale, have been previously implemented in various devices, including surface acoustic wave (SAW) sensors, chemical sensors, microelectromechanical systems, biosensors, and semiconducting nanowires.…”

Wearable Intracranial Pressure Monitoring Sensor for Infants

“…Although these pressure sensors have advantages of high sensitivity, linearity, and accuracy, their use in biomedical applications, particularly for wearable types, have been limited largely due to their low stress strength. To overcome such limitations, flexible sensors have become of interest to both academics and industries [23][24][25][26][27][28][29][30]. Liquid metals are a special family of materials that simultaneously possess the properties of both metals and liquids [31][32][33].…”