Multicolor Nitrogen-Doped Carbon Dots for Live Cell Imaging.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Nitrogen doping significantly enhances the fluorescence of carbon dots.
• The precise mechanism of nitrogen doping in carbon dots remains unclear.
• Carbon dots are promising nanomaterials for various applications due to their unique properties.

Purpose of the Study:

• To develop a facile synthesis method for photoluminescent nitrogen-doped carbon dots.
• To investigate the doping mechanism and structural characteristics of nitrogen-doped carbon dots.
• To evaluate the potential of these nitrogen-doped carbon dots as fluorescent probes for live cell imaging.

Main Methods:

• A bottom-up hydrothermal carbonization (HTC) process using glucose and glycine as precursors.
• Synthesis of mono-dispersed spherical nitrogen-doped carbon dots with a diameter of approximately 2.8 nm.
• Characterization of nitrogen configurations (pyridinic and pyrrolic) and internal structure.

Main Results:

• Successful synthesis of nitrogen-doped carbon dots with enhanced fluorescence.
• Nitrogen atoms incorporated into pyridinic and pyrrolic configurations, forming a new internal structure.
• Exhibited excitation wavelength-dependent multicolor photoluminescence.
• Demonstrated biocompatibility, efficient cellular uptake into A549 cancer cells, and localization within the cytoplasm and cell membrane.
• Showed no significant cytotoxicity.

Conclusions:

• The developed HTC method provides a facile route to synthesize photoluminescent nitrogen-doped carbon dots.
• Nitrogen doping introduces unique structural and optical properties, leading to multicolor fluorescence.
• These biocompatible nitrogen-doped carbon dots are suitable for multicolor live cell labeling, tracking, and imaging.