Highly Efficient Red-Emitting Carbon Dots with Gram-Scale Yield for Bioimaging

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Carbon dots (CDs) are versatile photoluminescent nanomaterials with desirable properties like biocompatibility and eco-friendliness.
• Developing efficient red-emitting carbon dots (R-CDs) on a large scale remains a significant challenge, limiting their bioimaging applications.

Purpose of the Study:

• To synthesize gram-scale R-CDs with high quantum yield (QY) for enhanced bioimaging.
• To investigate the properties and potential applications of these novel R-CDs.

Main Methods:

• Gram-scale synthesis of R-CDs via thermal treatment of citric acid and ethylenediamine in formamide.
• Characterization of R-CDs' size, nitrogen content, photoluminescence (PL) properties, and stability.
• Evaluation of R-CDs' cytotoxicity and performance as fluorescence probes in vitro and in vivo.

Main Results:

• Successful synthesis of R-CDs on a gram scale with a high QY of 53%.
• R-CDs exhibit excitation-independent red emission at 627 nm, average size of 4.1 nm, and ~30% nitrogen content.
• Strong red fluorescence attributed to nitrogen- and oxygen-related surface states and nitrogen-derived core structures.
• Demonstrated good photostability, low cytotoxicity, and effective performance in bioimaging.

Conclusions:

• The developed R-CDs are highly efficient, scalable, and suitable for bioimaging.
• These R-CDs represent a significant advancement in red fluorescence probes for both in vitro and in vivo applications.