Dual-Mode Fluorescence/Ultrasound Imaging with Biocompatible Metal-Doped Graphene Quantum Dots

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Ultrasound imaging is a cost-effective, non-invasive diagnostic tool with deep tissue penetration.
• Current ultrasound lacks high-precision imaging, necessitating complementary techniques.
• Development of ultrasound-trackable drug delivery vehicles is crucial for targeted therapies.

Purpose of the Study:

• To develop novel metal-doped nitrogen-containing graphene quantum dots (NGQDs) for combined ultrasound and fluorescence imaging.
• To evaluate the theranostic potential of these NGQDs for enhanced diagnostic and therapeutic applications.

Main Methods:

• Synthesis of various metal-doped NGQDs (Fe, Ag, Tm, Nd, Ce, MoS2) from glucosamine precursors.
• Characterization of NGQD properties including ultrasound contrast, fluorescence imaging (visible/NIR), cell viability, and cellular uptake.
• Assessment of ultrasound signal enhancement in phantoms and animal tissues.

Main Results:

• Metal-doped NGQDs exhibited high-contrast ultrasound properties and visible/NIR fluorescence.
• Synthesized NGQDs showed low in vitro toxicity (>80% cell viability at 2 mg/mL) and effective cell internalization (<50 nm).
• Significant 10-fold ultrasound signal enhancement was observed in various phantoms and tissues at 0.5-1.6 mg/mL concentrations.

Conclusions:

• Metal-doped NGQDs offer a promising platform for advanced theranostic applications by combining ultrasound and fluorescence imaging.
• These NGQDs demonstrate excellent biocompatibility, water solubility, and potential for drug conjugation.
• The developed NGQDs significantly enhance ultrasound imaging capabilities, paving the way for improved diagnostic precision.