Coumarin-Modified CQDs for Biomedical Applications-Two-Step Synthesis and Characterization.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Waste biomass, specifically lignin, is a sustainable precursor for synthesizing carbon quantum dots (CQDs).
• Carbon quantum dots offer superior luminescent properties, water solubility, and biocompatibility compared to traditional organic dyes.
• Advanced CQDs are crucial for developing novel diagnostic and cell visualization methods in medicine.

Purpose of the Study:

• To synthesize novel coumarin-modified carbon quantum dots (CQDs) using a hybrid approach.
• To characterize the synthesized CQDs for their chemical structure, morphology, and fluorescence properties.
• To evaluate the potential applications of these CQDs in biomolecule detection, bioimaging, and nanomedicine.

Main Methods:

• A two-step hybrid synthesis involving hydrothermal carbonization of waste biomass.
• Microwave-assisted surface modification of carbon quantum dots with coumarin derivatives (coumarin-3-carboxylic acid and 7-(Diethylamino) coumarin-3-carboxylate).
• Characterization of chemical structure and morphology, fluorescence spectroscopy, quantum yield determination, cytotoxicity assay (XTT), and real-time bioimaging.

Main Results:

• Successful synthesis of coumarin-modified carbon quantum dots with superior fluorescence characteristics.
• Achieved a high quantum yield of up to 18.40%.
• Demonstrated fluorescence quenching for biomolecule and ion detection, confirmed lack of cytotoxicity in L929 mouse fibroblasts, and showed applicability in real-time bioimaging.

Conclusions:

• The developed coumarin-modified carbon quantum dots offer enhanced fluorescence and sensing capabilities.
• These nanomaterials exhibit excellent biocompatibility and are suitable for in vitro applications like bioimaging.
• The surface-modified CQDs present a promising platform for advancements in nanomedicine and pharmaceutical applications.