Development of electrochemical paper-based analytical device for detection of Pseudomonas aeruginosa in water and saliva samples

Pseudomonas aeruginosa is a versatile and opportunistic human pathogen with an exceptional resistance to a wide range of antibiotics. Currently, it is one of the major human pathogens associated with serious illnesses – hospital-acquired infections.1 Usually, the bacterial infection is detected by lab-based methods like culturing the microorganisms on agar plates followed by standard biochemical identifications (Polymerase Chain Reaction, imunoassays, etc)2, that are laborious and time consuming. So, it is extremely relevant the development of portable, simple and rapid analytical tools to assist in the detection and monitoring of this kind of bacterial infection, especially in centers lacking laboratory infrastructure and with high clinical demand. In this work, we demonstrate the fabrication of portable electrochemical paper-based analytical device (ePAD) using two graphite leads and conductive silver ink as working, auxiliary and pseudo-reference electrode, respectively. The devices were fabricated in filter paper and patterned by wax-printing method. The monitoring of P. aeruginosa was conducted indirectly by Pyocyanin (PYO), a major metabolite used as key biomarker3. PYO is a redox active compound that exhibit two reversible electrochemical processes closed zero volts, providing a selective detection. The analytical method was performed using square wave voltammetry in 0.1 M phosphate buffer pH = 7.0 for clinical (simulated saliva) and water analyses. Our ePAD is simple, inexpensive and offer fast detection of bacterial infection caused by P. aeruginosa with suitable repeatability (~5%), and great sensitivity (nanomolar range). These analytical features allow indicate the potential use of this device to remote places or resource-limited settings.