Highly Selective, Aptamer-Based, Ultrasensitive Nanogold Colorimetric Smartphone Readout for Detection of Cd(II)

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Environmental Science

Background:

• Cadmium (Cd(II)) is a toxic heavy metal pollutant.
• Accurate detection of Cd(II) is crucial for environmental monitoring and food safety.
• Existing detection methods can be expensive and time-consuming.

Purpose of the Study:

• To develop a highly selective and sensitive method for Cd(II) detection.
• To integrate aptamers and gold nanoparticles (AuNPs) with a smartphone-based colorimetric readout.
• To validate the method's performance and applicability in real samples.

Main Methods:

• Optimization of experimental conditions including polydiene dimethyl ammonium chloride (PDDA) reaction time and dose, and aptamer incubation time and concentration.
• Utilized aptamer-functionalized gold nanoparticles (AuNPs) for Cd(II) recognition.
• Employed a smartphone for colorimetric readout of Cd(II) concentration.

Main Results:

• Achieved a linear detection range of 1-400 ng/mL for Cd(II).
• Established a low limit of detection (LOD) of 1 ng/mL.
• Demonstrated successful application in quantifying Cd(II) in water and rice samples, with results consistent with atomic absorption spectrometry.

Conclusions:

• The aptamer-AuNP colorimetric method offers a sensitive, selective, and low-cost approach for Cd(II) detection.
• Smartphone integration enables practical visual or quantitative analysis.
• The methodology shows potential for broader application in detecting other analytes.