Multi-targets detection via combination of multi-stimulus-response engineered bacteria and hydrogel-based separation...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Simultaneous, in situ quantification of multiple heavy metals remains a challenge.
• Existing methods like ICP-MS can be cumbersome and require sample pre-treatment.
• Need for convenient and accurate heavy metal detection in environmental monitoring.

Purpose of the Study:

• To develop a novel biosensor for simultaneous, convenient, and in situ detection of multiple heavy metals.
• To engineer Escherichia coli with specific sensing and fluorescence reporting elements for target heavy metals.
• To utilize a hydrogel-based separation platform for signal differentiation and quantification.

Main Methods:

• Engineered *Escherichia coli* with integrated sensing and fluorescence reporting elements for heavy metals (Cd(II), Hg(II), As(III), Pb(II)).
• Constructed a hydrogel-based separation platform to differentiate overlapping fluorescence signals.
• Optimized hydrogel adsorption strength to adjust detection limits and sensitivity.

Main Results:

• Achieved low detection limits for Cd(II) (1.249 μg/L), Hg(II) (0.380 μg/L), As(III) (3.917 μg/L), and Pb(II) (0.755 μg/L).
• Demonstrated successful application in detecting coexisting heavy metals in actual samples with high recovery rates (85.61-110.30%).
• Results showed strong agreement with classical ICP-MS detection, confirming accuracy and reliability.

Conclusions:

• The developed engineered bacteria and hydrogel platform provide an accurate and reliable method for simultaneous heavy metal detection.
• This biosensor system offers a convenient and in situ alternative for analyzing multiple heavy metals in environmental samples.
• The approach effectively overcomes challenges of signal overlap and quantification in complex samples.