Fluorometric aptasensor for cadmium(II) by using an aptamer-imprinted polymer as the recognition element

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Cadmium (Cd(II)) is a toxic heavy metal pollutant with significant environmental and health concerns.
• Accurate and sensitive detection methods for Cd(II) in complex matrices are crucial for environmental monitoring and food safety.

Purpose of the Study:

• To develop a highly selective and sensitive fluorometric sensor for the determination of Cd(II) in environmental and agricultural samples.
• To utilize a dual-recognition system combining molecularly imprinted polymers (MIPs) and aptamers for enhanced Cd(II) detection.

Main Methods:

• Fabrication of a sensor using aptamer-modified MIP on a sulfur and nitrogen co-doped carbon quantum dots/gold nanoparticle (SN-CQD/Au) modified electrode.
• Utilizing the fluorescence quenching effect of Cd(II) for detection, with excitation/emission peaks at 370/430 nm.
• Validation of the sensor's performance with real-world environmental and agricultural samples.

Main Results:

• The sensor exhibited high selectivity for Cd(II) through the dual-recognition mechanism of the aptamer-MIP system.
• A linear response range for Cd(II) was observed from 20 pM to 12 nM, with a low detection limit of 1.2 pM.
• Successful recovery rates (82.1–113.9%) were achieved for Cd(II) in spiked water, soil, and vegetable samples.

Conclusions:

• The developed SN-CQD/Au-based aptamer-MIP sensor offers a promising platform for sensitive and selective fluorometric determination of Cd(II).
• This sensor demonstrates practical applicability for monitoring cadmium contamination in environmental and agricultural settings.