Ligands dissociation induced gold nanoparticles aggregation for colorimetric Al³⁺ detection

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Materials Science

Background:

• Aluminum (Al3+) is a critical analyte requiring sensitive detection methods.
• Existing colorimetric sensors based on gold nanoparticles (AuNPs) often rely on interparticle crosslinking for aggregation.
• A novel mechanism for Al3+ detection using AuNPs is needed to expand sensor design principles.

Purpose of the Study:

• To develop a novel colorimetric sensor for Al3+ detection using gold nanoparticles (AuNPs).
• To elucidate the aggregation mechanism of AuNPs induced by Al3+.
• To demonstrate the practical application of the developed sensor in real-world samples.

Main Methods:

• Synthesis of AuNPs using catechols as reductants and capping agents.
• Investigation of Al3+-induced AuNPs aggregation mechanism via ligand dissociation.
• Testing the sensor's sensitivity, selectivity, and application in river water and food samples.

Main Results:

• AuNPs prepared with catechols showed high sensitivity and selectivity for Al3+ detection without post-modification.
• Mechanistic studies revealed Al3+ induces aggregation by dissociating capping ligands from the AuNPs surface, not through interparticle crosslinks.
• Dopamine-derived AuNPs (AuNPs/DA) exhibited the highest sensitivity with a detection limit of 0.81 μM.
• The sensor successfully analyzed Al content in river water and food samples.

Conclusions:

• A novel mechanism for Al3+-induced AuNPs aggregation, based on ligand dissociation, was discovered.
• This work expands the design principles for developing AuNPs-based colorimetric sensors.
• The developed sensor demonstrates practical applicability for Al3+ determination in environmental and food samples.