In Brain Multi-Photon Imaging of Vaterite Drug Delivery Cargoes loaded with Carbon Dots

TL;DR

This paper demonstrates the use of biocompatible carbon dots loaded into vaterite nanoparticles for multi-photon brain imaging and drug delivery, showing potential for real-time in vivo tracking and imaging.

Contribution

It introduces a novel combination of carbon dots and vaterite nanoparticles for simultaneous imaging and drug delivery in brain tissues.

Findings

Carbon dots exhibit strong nonlinear optical properties suitable for multiphoton imaging.

Vaterite nanoparticles loaded with carbon dots enable effective in vivo brain vessel imaging.

The platform allows real-time monitoring of nanoparticle flow in live mouse brain.

Abstract

Biocompatible fluorescent agents, such as phenylenediamine carbon dots (CDs), are key contributors to the theragnostic paradigm, enabling real-time in vivo imaging of drug delivery cargoes. This study explores the optical properties of these CDs, demonstrating their potential for two-photon fluorescence imaging in brain vessels. Using an open aperture z-scan technique, we measured the wavelength-dependent nonlinear absorption cross-section of the CDs, achieving a peak value near 50 GM. This suggests the potential use of phenylenediamine CDs for efficient multiphoton excitation in the 775 - 895 nm spectral range. Mesoporous vaterite nanoparticles were loaded with fluorescent CDs to examine the possibility of a simultaneous imaging and drug delivery platform. Efficient one and two-photon imaging of the CD-vaterite composites, uptaken by macrophage and genetically engineered C6-Glioma cells, was demonstrated. For an in vivo scenario, vaterite nanoparticles loaded with CDs were directly injected into the brain of a living mouse, and their flow was monitored in real-time within the blood vessels. The facile synthesis of phenylenediamine carbon dots, their significant nonlinear responses, and biological compatibility show a viable route for implementing drug tracking and sensing platforms in living systems.