Wearable flexible pH sensor for biomedical applications

Abstract

In this project, a screen-printed flexible chemiresistive sensor based on polyaniline emeraldine salt (PANI (ES)) and single-walled carbon nanotubes (SWCNT) on PET substrates is presented. Smart Bandages with embedded sensors can help determine the health of damaged tissue cells and the status of the bandage itself by detecting the pH of the fluid analyte from the wound. One of the most important parameters that changes in wounds in different states is pH, which could help bring added value to patients and health actioners in identifying the onset of infection. Chemiresistive sensors operate in the presence of a chemical target based on electrical changes in resistance. An optimised solution of SWCNTs/PANI (ES) (60/40 wt%) solution was drop-casted on top of flexible silver electrodes screen printed on a polyethylene terephthalate substrate. The sensor was annealed at an optimised temperature of 90 C for 1 hour with a subsequent PANI (ES) drop-casted and annealing step. The developed chemiresistive pH sensor achieved high signal stability, sensitivity of 2.72 pH, linearity in the pH range of 2–10, and response times of 70 seconds. The pH sensitivity of the SWCNTs/PANI nanocomposite depends on the protonation/deprotonation process. The chemiresistive sensor can monitor the changes in the resistance of nanocomposite films (SWCNT, PANI) in different ranges of pH. By using printed electronic fabrication methods, we can develop chemiresistive sensors, which will be a key component of our smart medical bandage system. They also have the potential for differentapplications, such as agriculture, industries, food packaging, and water monitoring.

Date	8 Apr 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Ricardo Izquierdo (Supervisor)