An Affordable Microsphere-Based Device for Visual Assessment of Water Quality.

Azra Rajwani,Nathan J Muller,Brendon Restall,Stephanie M Willerth,Scott Roebuck

doi:10.3390/bios7030031

Abstract

This work developed a prototype of an affordable, long-term water quality detection device that provides a visual readout upon detecting bacterial contamination. This device prototype consists of: (1) enzyme-releasing microspheres that lyse bacteria present in a sample, (2) microspheres that release probes that bind the DNA of the lysed bacteria, and (3) a detector region consisting of gold nanoparticles. The probes bind bacterial DNA, forming complexes. These complexes induce aggregation of the gold nanoparticles located in the detector region. The nanoparticle aggregation process causes a red to blue color change, providing a visual indicator of contamination being detected. Our group fabricated and characterized microspheres made of poly (ε-caprolactone) that released lysozyme (an enzyme that degrades bacterial cell walls) and hairpin DNA probes that bind to regions of the Escherichia coli genome over a 28-day time course. The released lysozyme retained its ability to lyse bacteria. We then showed that combining these components with gold nanoparticles followed by exposure to an E. coli-contaminated water sample (concentrations tested—106 and 108 cells/mL) resulted in a dramatic red to blue color change. Overall, this device represents a novel low-cost system for long term detection of bacteria in a water supply and other applications.

Highlights

The World Health Organization estimated that 842,000 deaths in lower to middle income countries are caused by inadequate water supplies, sanitation, and hygiene in 2014 [1]
We developed a novel prototype of an affordable, long-term water quality biosensing device uses microspheres to deliver both lysozyme and DNA probes in combination with gold nanoparticles that uses microspheres to deliver both lysozyme and DNA probes in combination with gold for detecting the presence of E. coli. in a water sample
The lysozyme breaks down the cell walls of the nanoparticles for detecting the presence of E. coli. in a water sample

Summary

Introduction

The World Health Organization estimated that 842,000 deaths in lower to middle income countries are caused by inadequate water supplies, sanitation, and hygiene in 2014 [1]. Developing affordable and rapid methods for detecting water quality that can be implemented in these regions could lead to a reduction in unsafe water consumption [2]. These systems could be applied in isolated regions of developed countries to quickly determine whether bacteria have contaminated a water source [3]. Such water quality testing plays an important role in preventing disease outbreaks caused by contaminated infrastructure [4].

Methods

Results

Conclusion