In-Brain Multiphoton Imaging of Vaterite Cargoes Loaded with Carbon Dots

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Biocompatible fluorescent agents are crucial for theranostic applications, enabling real-time in vivo imaging.
• Carbon dots (CDs) offer unique optical properties for bioimaging.
• Developing safe and effective imaging platforms is essential for advanced medical diagnostics.

Purpose of the Study:

• To explore the optical properties of phenylenediamine carbon dots (CDs).
• To evaluate the potential of CD-loaded mesoporous vaterite nanoparticles as a biocompatible imaging platform.
• To demonstrate the utility of this platform for in vitro and in vivo fluorescence imaging.

Main Methods:

• Characterization of phenylenediamine carbon dots (CDs) optical properties, including nonlinear absorption.
• Loading CDs into mesoporous vaterite nanoparticles to create a composite imaging agent.
• In vitro imaging of CD-vaterite composites in various cell types using one- and two-photon microscopy.
• In vivo imaging of CD-vaterite composite circulation in mouse brain blood vessels via cranial window.

Main Results:

• Phenylenediamine carbon dots exhibited a nonlinear absorption cross-section near 50 Goeppert-Mayer (GM) units.
• Efficient excitation of CDs was achieved in the 775-895 nm spectral range.
• CD-vaterite composites demonstrated efficient one- and two-photon imaging in diverse cells.
• In vivo monitoring of CD-vaterite composite flow in mouse cerebral vasculature was successful.

Conclusions:

• Phenylenediamine carbon dots integrated with vaterite nanoparticles form a promising biocompatible platform for high-brightness fluorescence imaging.
• The developed platform shows potential for advanced theranostic applications, including simultaneous sensing and drug delivery.
• This study highlights the utility of CD-vaterite composites for both cellular and in vivo imaging of biological systems.