Deep Red Emissive Carbonized Polymer Dots with Unprecedented Narrow Full Width at Half Maximum

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Imaging

Background:

• Developing carbon dots (CDs) for deep-tissue bioimaging requires emission beyond 660 nm (deep red).
• Achieving narrow full width at half maximum (FWHM) and high emission yield simultaneously in deep red CDs remains a significant challenge.

Purpose of the Study:

• To synthesize novel deep red emissive carbonized polymer dots (CPDs) with improved photophysical properties.
• To evaluate the potential of these CPDs as efficient probes for deep-tissue bioimaging applications.

Main Methods:

• Synthesis and purification of deep red emissive carbonized polymer dots (CPDs).
• Characterization of CPDs' photophysical properties, including quantum yield (QY) and full width at half maximum (FWHM).
• Assessment of CPDs' biocompatibility, toxicity, and in vivo excretion pathways.

Main Results:

• Synthesized CPDs exhibit unprecedented narrow FWHM of 20 nm.
• High quantum yields (QY) of 59% (413 nm excitation) and 31% (660 nm excitation) were recorded in the deep red region.
• CPDs demonstrated low toxicity, good biocompatibility, and rapid excretion via renal and hepatobiliary systems.

Conclusions:

• The unique polymer structure and conjugated π system of CPDs enable efficient deep red emission with narrow FWHM.
• CPDs are promising candidates for advanced one-photon and two-photon bioimaging due to their spectral properties and biocompatibility.
• Rapid in vivo clearance suggests a favorable safety profile for biomedical applications.