• Rengaraj, Saravanan
• Scott, Janet L.
• Lorenzo, Mirella Di
• Cruz-Izquierdo, Alvaro

Abstract

<p>According to the World Health Organisation, worldwide waterborne diseases are responsible for nearly two million human deaths annually. Rapid and at-site screen of pathogenic microorganisms in drinking water can help to markedly reduce this number. Here we report an innovative, simple and low-cost, paper-based probe for detection of bacteria in water, fabricated by screen printing carbon electrodes onto hydrophobic paper. Electrochemical characterization of the printed electrodes confirmed fast-electron transfer, with an estimated electroactive surface area of 0.25 cm². The electrode surface was functionalised with carboxyl groups, prior to covalent immobilization of the lectin Concanavalin A (Con A), used as the biorecognition element. The system was then tested as an impedimetric sensor for bacteria in water. A linear increase in the probe charge transfer resistance was observed for bacterial concentrations ranging from 10³ to 10⁶ CFU mL⁻¹, with an estimated lower detection limit of 1.9 × 10³ CFU mL⁻¹. Considering its remarkable simplicity, cost-effectiveness and biodegradability, the sensor here reported could be an attractive solution for portable testing kits that address the challenges of traditional time-consuming and expensive lab-based analyses.</p>

Topics

• surface
• Carbon