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An innovative biotechnology development offers a new approach to detecting and destroying dangerous E. coli bacteria directly in drinking water, which could fundamentally change global methods for ensuring safe water.
Problems with traditional approaches
Current methods for detecting bacteria in water have significant limitations. Culturing and polymerase chain reaction (PCR) are time-consuming and require specialized equipment. These methods also require skilled personnel to perform the tests and interpret the results.
Although existing biosensors are faster, they rely on external power sources and their efficiency decreases over time due to degradation of biological components. The new biosensor overcomes these obstacles thanks to a unique three-link system.
Innovative three-link system
The first component is an enzymatic biofuel cell (EBFC), which provides autonomous power. It uses the enzyme glucose oxidase to break down glucose, resulting in the production of electrons and hydrogen peroxide. This process essentially converts biochemical energy into electrical energy.
To prevent the enzyme from degrading, the researchers developed a protective shell. They encapsulated glucose oxidase in a hollow metal-organic framework called ZIF-8, which protects the enzyme from external damage and maintains its stability.
The second element is an aptamer-based detection system. These specialized short DNA strands can specifically bind to components of the outer shell of E. coli. The aptamers are linked to silver nanoparticles that block glucose from reaching the enzyme.
When E. coli is introduced into the water, a chain reaction occurs. The aptamers bind to the bacteria, which initiates an interaction with the silica barrier. This opens a path for glucose to reach the enzyme, triggering an oxidation reaction. The resulting electrical signal confirms the presence of the bacteria.
The third component is a system for destroying detected bacteria. This elimination mechanism uses hydrogen peroxide, a byproduct of the biofuel cell. Peroxide oxidizes silver nanoparticles, releasing silver ions, which are known for their powerful antibacterial properties.
Advantages of an innovative biosensor
The developed biosensor demonstrates extraordinary sensitivity, detecting E. coli even at a concentration of 3 CFU/mL. The detection accuracy is enhanced by a catalytic hairpin assembly mechanism that forms double-stranded DNA structures to amplify the electrical signal.
Testing showed high specificity of the biosensor – it clearly distinguishes E. coli from other bacteria, such as Staphylococcus aureus and Salmonella. The device retains functionality with repeated use and after long-term storage. In real seawater samples, the detection accuracy ranged from 91,06% to 101,9%.
The antibacterial component of the biosensor is impressive in its effectiveness – silver ions destroy 99,9% of detected bacteria within a few hours. This makes the technology not only a diagnostic tool, but also an active means of water purification.
Prospects and caveats
Despite the promising results, the researchers acknowledge that further study is needed. The question of whether the technology can be scaled up for widespread use remains open. There is also concern about the potential accumulation of silver ions in the environment.
Although silver ions are effective in killing pathogenic bacteria, they can have negative effects on beneficial microorganisms. Therefore, it is necessary to develop mechanisms for controlled release of silver ions to minimize environmental impact while maintaining antimicrobial efficacy.
Despite these caveats, the new biosensor represents a significant step forward in water purification technologies. Its ability to autonomously detect and destroy pathogens makes it a potentially revolutionary tool for ensuring safe drinking water worldwide.
Scientists Create Autonomous Sensor to Purify Drinking Water appeared first on Curiosity.
