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Ultra-sensitive detection of malathion using quantum dots-polymer based fluorescence aptasensor.

Rajni Bala¹, Anuradha Swami², Ilja Tabujew³

¹Department of Chemistry & Centre for Advanced Studies in Chemistry, Panjab University, Sector 14, Chandigarh 160014, India.

Biosensors & Bioelectronics

|January 7, 2018

Summary

A new nanoprobe using quantum dots (QDs) and aptamers offers highly specific and sensitive detection of the pesticide malathion. This fluorescence-based assay achieves a low detection limit, enabling accurate quantification in agricultural samples.

Keywords:

Aptamer Core shell quantum dots Fluorescence quenching Guanidinium-containing polymers Malathion

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Area of Science:

Nanotechnology
Analytical Chemistry
Environmental Science

Background:

Malathion is a widely used organophosphate pesticide with significant environmental and health implications.
Accurate and sensitive detection methods are crucial for monitoring malathion levels in agricultural and environmental samples.
Existing detection methods may lack specificity or require complex procedures.

Purpose of the Study:

To develop a novel, highly specific, and sensitive fluorescence-based detection platform for malathion.
To utilize cadmium telluride/cadmium sulfide core/shell quantum dots (CdTe@CdS QDs) functionalized with a malathion-specific aptamer and a cationic polymer.
To establish a quantitative assay for malathion with a low detection limit and high selectivity.

Main Methods:

Fabrication of a nanoprobe incorporating CdTe@CdS QDs, poly(N-(3-guanidinopropyl)methacrylamide) (PGPMA), and a malathion-specific aptamer.
Exploitation of fluorescence quenching mechanism: aptamer-malathion interaction in the presence of PGPMA leads to fluorescence quenching of QDs.
Characterization of the assay's sensitivity, selectivity, and quantitative range using fluorescence spectroscopy.

Main Results:

The developed nanoprobe demonstrated high specificity for malathion detection.
An excellent sensitivity was achieved with a detection limit as low as 4 picomolar (pM).
A logarithmic correlation between fluorescence signal and malathion concentration was observed over a wide range (0.01 nM to 1 μM), indicating quantitative potential.
The probe showed high selectivity, unaffected by the presence of other common agricultural pesticides.

Conclusions:

The novel aptamer-functionalized QD nanoprobe provides a sensitive and selective platform for malathion detection.
The fluorescence quenching mechanism offers a reliable basis for quantitative analysis of malathion in complex matrices.
This assay holds significant promise for environmental monitoring and food safety applications.