Development of a low-cost electrochemical sensor array for rapid detection of waterborne pathogens in drinking water.

Project Abstract

This study reports the design, fabrication, and validation of a low-cost electrochemical sensor array capable of rapid detection of waterborne pathogens in drinking water. The sensor platform integrates a miniaturized multi-electrode array (MEA) with screen-printed carbon electrodes functionalized by selective biorecognition elements, enabling simultaneous multiplexed detection of bacterial, viral, and protozoan targets commonly associated with drinking water contamination. The core sensing mechanism relies on impedimetric and voltammetric interrogation, where binding events between target pathogens and immobilized aptamers and antibodies induce measurable changes in charge transfer resistance and peak currents. A three-tier data acquisition strategy combines high-sensitivity differential measurements with a reference channel to compensate for matrix effects inherent to natural water samples, such as varying ionic strength, pH, and organic matter content. Fabrication of the sensor array emphasizes accessibility and cost-efficiency, employing screen-printed substrates, minimal-use of noble metals, and scalable surface chemistry protocols that preserve selectivity while reducing manufacturing variability. To enhance practicality in resource-limited settings, the device is paired with a low-power, battery-operated potentiostat and a compact microcontroller-based readout unit, enabling field deployment and real-time analysis. The study introduces a robust sample preparation workflow that integrates lightweight filtration and pre-concentration steps to improve target capture without compromising speed, yielding results within 20–30 minutes from sample collection. The detection limit achieved for representative pathogens—including Escherichia coli O157H7, Salmonella spp., Norovirus, and Giardia lamblia—meets regulatory thresholds for rapid screening in drinking water, with linear dynamic ranges spanning several orders of magnitude to accommodate both trace contamination and moderate contamination scenarios. Analytical performance is validated through spiked water samples, simulated groundwater, and municipal water matrices, with emphasis on selectivity against non-target microorganisms and common interferents such as humic acids and chlorinated species. Cross-reactivity studies demonstrate high specificity afforded by the combined use of aptamer- and antibody-based recognition elements and optimized surface passivation. The sensor array demonstrates reproducibility across multiple fabrication batches, with inter-electrode variability minimized through standardized printing and surface chemistry protocols. A calibration framework based on machine learning-assisted pattern recognition of the multiplexed electrochemical signals is developed to translate raw impedimetric data into actionable concentration estimates with quantified uncertainty. Field validation is conducted at several community water sources, comparing sensor outputs against gold-standard culture-based assays and molecular methods (qPCR). Results indicate strong concordance with established methods, while delivering significantly shorter turnaround times and reduced operational costs. The study also assesses durability under varying environmental conditions, including temperature fluctuations and prolonged usage, demonstrating acceptable sensor stability over typical field deployment windows. The final system presents a pathway for scalable deployment in water quality monitoring networks, with potential integration into Internet of Things (IoT) architectures for centralized surveillance, rapid response, and decision-making in public health protection.

Project Overview

What This Project Is About

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A straightforward, hands-on study of a small, affordable sensor array that can detect common waterborne pathogens in drinking water. The project explores building a set of sensors that respond to the presence of bacteria or other microbes and turning those responses into a simple signal we can measure and interpret.

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The Problem It Addresses

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Drinking water can be contaminated by disease-causing organisms, but rapid, on-site testing is often expensive or slow. This project aims to create a low-cost alternative that provides quick, actionable results to improve water safety and public health.

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Objectives of the Project

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1. Understand how electrochemical sensing works in simple terms.
2. Design a small sensor array that can detect multiple common pathogens.
3. Develop a low-cost data interface to read sensor signals.
4. Evaluate the sensitivity and specificity of the sensors with real water samples.
5. Identify practical limitations and propose improvements for field use.

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What You Will Do Step by Step

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1) Learn basic sensor concepts and safety; 2) Assemble inexpensive sensor components; 3) Calibrate sensors using known samples; 4) Test with various water samples and record readings; 5) Analyze data to assess detection accuracy; 6) Compare results to standard methods; 7) Document design, results, and limitations; 8) Suggest practical deployment steps for real-world use.

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Expected Outcome

A functional, low-cost sensor array capable of indicating the presence of waterborne pathogens with clear readouts, plus a report detailing performance, limitations, and potential deployment scenarios.