Environmentally exploitable biocide/fluorescent metal marker carbon quantum dots

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Metal-based nanostructures pose environmental and health risks.
• Carbon quantum dots (CQDs) offer a safer, eco-friendly alternative due to their low toxicity and biocompatibility.
• Developing green synthesis methods for CQDs is crucial for sustainable environmental applications.

Purpose of the Study:

• To develop a simple, green synthesis for biocide and fluorescent marker carbon quantum dots (CQDs).
• To evaluate the efficacy of synthesized CQDs as fluorescent probes for environmental pollutant detection (Zn2+ and Hg2+).
• To assess the antimicrobial properties of CQDs against common bacterial and fungal pathogens.

Main Methods:

• Synthesized CQDs using a green technique involving alkaline fragmentation and hydrothermal re-polymerization of natural biopolymers.
• Purified CQDs via dialysis, achieving a size distribution of 1.5-6.5 nm.
• Characterized CQDs for fluorescence properties and evaluated their performance in detecting Zn2+ and Hg2+ ions and their antimicrobial activity.

Main Results:

• Achieved a 20-fold increase in fluorescence intensity after dialysis.
• Successfully utilized CQDs as fluorescent markers for sensitive detection of Zn2+ and Hg2+.
• Demonstrated significant antimicrobial potency against Bacillus cereus, Escherichia coli, and Candida albicans with a minimal inhibitory concentration of 350-450 μL mL-1.

Conclusions:

• The presented green synthesis offers a scalable, cost-effective method for producing biocide/fluorescent CQDs.
• These CQDs are a promising, non-toxic alternative to metal-based nanostructures for environmental monitoring and antimicrobial applications.
• The study highlights the potential of biopolymer-derived CQDs in addressing environmental challenges safely and sustainably.