Towards a targeted Escherichia coli fluorescent biosensor using quantum-dot-decorated geothermal silica nanoparticles

Area of Science:

• Nanotechnology
• Environmental Science
• Biotechnology

Background:

• Water quality monitoring is crucial for public health, with Escherichia coli (E. coli) being a key indicator of fecal contamination and a cause of waterborne diseases.
• Current detection methods for E. coli can be time-consuming and lack the sensitivity required for rapid public health interventions.

Purpose of the Study:

• To develop a highly sensitive and rapid fluorescent biosensor for the detection of E. coli in water samples.
• To utilize quantum-dot-modified silica nanoparticles functionalized with antibodies for enhanced specificity and sensitivity.

Main Methods:

• Synthesis of silica nanoparticles (SiNP) and modification with amine-CdSe quantum dots (QD) to create SiNP@QD.
• Immobilization of E. coli antibodies onto SiNP@QD to form the SiNP@QD-Ab biosensor.
• Characterization of nanoparticles using BET, FESEM, and XRD; detection of E. coli using fluorescence spectrophotometry.

Main Results:

• The SiNP@QD-Ab biosensor demonstrated high sensitivity with a limit of detection (LOD) of 1.6 CFU mL⁻¹ for E. coli.
• Optimal detection was achieved with a 15-minute incubation time.
• The biosensor showed specific fluorescence detection in the 400-800 nm range upon excitation at 360 nm.

Conclusions:

• The developed SiNP@QD-Ab biosensor provides a swift, accurate, and highly sensitive method for E. coli detection.
• This platform holds significant potential for improving water safety, environmental monitoring, and public health surveillance.