A pH-based biosensor for detection of arsenic in drinking water

Arsenic contamination in water remains a major public health issue, particularly in regions like Bangladesh and West Bengal. Previous research has highlighted the scale of the problem, but no single solution has yet met the needs of affordability and accuracy in field settings. Existing methods often require costly equipment or specialized training. A portable, user-friendly device is still needed to detect low levels of arsenic in drinking water. Visual detection methods have been explored, but sensitivity and reliability have remained challenges. This gap motivated the development of a new approach using biological systems to detect arsenic. The focus has been on creating a system that can be used without laboratory infrastructure. The goal is to provide a tool that can be deployed in remote or resource-limited areas.

The aim of this work is to refine a previously developed biosensor for arsenic detection in drinking water. The sensor relies on a pH change as a measurable output, which can be observed through a color shift using a pH indicator. The study seeks to improve the sensitivity and accuracy of the biosensor to detect arsenate at levels below 10 ppb. A key objective is to enable static overnight incubation, reducing the need for continuous monitoring. The researchers also aim to develop a high-throughput system for monitoring multiple samples simultaneously. The goal is to make the system affordable and easy to use in the field. The study tests the feasibility of storing and distributing the biosensor in air-dried or freeze-dried forms. The ultimate purpose is to create a device suitable for field trials in affected regions.

The biosensor is based on a biological system that produces a pH change in the presence of arsenate. The pH change is visualized using a pH indicator that changes color. The system was optimized to detect arsenate at concentrations below 10 ppb. Static overnight incubation was used to simplify the detection process. A high-throughput setup was developed to monitor 50 samples simultaneously over time. The system allows for continuous monitoring of pH changes in multiple assays. The biosensor cells were prepared in both air-dried and freeze-dried forms for storage and distribution. Field testing was conducted using groundwater samples from the South East region of Hungary.

The improved biosensor detected arsenate at concentrations below 10 ppb using static overnight incubation. The color change was clearly visible and correlated with the arsenate concentration. The high-throughput system successfully monitored up to 50 samples simultaneously. Continuous monitoring over time showed consistent and reliable results. Air-dried and freeze-dried cells remained stable and functional for the biosensor. The system was tested on real groundwater samples from Hungary, confirming its effectiveness. The results suggest the biosensor is suitable for field use. The method offers a cost-effective and accurate alternative to traditional testing methods.

The biosensor provides a sensitive and accurate method for detecting arsenate in drinking water. The use of a pH indicator allows for visual detection without specialized equipment. Static overnight incubation simplifies the process for field use. The high-throughput system supports monitoring multiple samples at once. Air-dried and freeze-dried cells enable easy storage and distribution. Field testing in Hungary confirmed the system's reliability. The biosensor is a promising tool for field trials in arsenic-affected regions. The authors propose further development to refine the device for widespread deployment.