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Fluorescently Labeled PLGA Nanoparticles for Visualization In Vitro and In Vivo: The Importance of Dye Properties
Vasilisa Zhukova1, Nadezhda Osipova1, Aleksey Semyonkin1
1Drug Delivery Systems Laboratory, D. Mendeleev University of Chemical Technology of Russia, Miusskaya pl. 9, 125047 Moscow, Russia.
Pharmaceutics
|August 28, 2021
Summary
Dye leakage from fluorescent nanoparticles can distort biodistribution studies. This research shows covalently bound dyes offer reliable tracking, preventing misinterpretation of nanoparticle delivery, unlike encapsulated dyes that may detach.
Area of Science:
- Nanotechnology
- Biomedical Engineering
- Materials Science
Background:
- Fluorescently labeled nanoparticles are crucial for in vivo tracking.
- Dye leakage from nanoparticles can lead to inaccurate biodistribution data.
- Understanding dye-nanoparticle-environment interactions is vital for reliable imaging.
Purpose of the Study:
- To investigate the stability of different fluorescent dyes (coumarin 6, rhodamine 123, DiI, Cy5.5) associated with PLGA nanoparticles.
- To determine how dye encapsulation or covalent binding affects dye retention in biological environments.
- To assess the impact of dye leakage on the interpretation of in vivo nanoparticle imaging results.
Main Methods:
- PLGA nanoparticles were labeled with four dyes via encapsulation or covalent binding.
- Dye stability was assessed in aqueous and lipophilic environments, including albumin and liposomes.
- Computational modeling was used to predict dye-polymer and dye-lipid affinities.
- In vivo neuroimaging of rat retinas was performed using double-labeled nanoparticles (Cy5.5/Cou6).
Main Results:
- DiI exhibited high stability in both aqueous and lipophilic conditions.
- Coumarin 6 showed rapid release in the presence of albumin and liposomes.
- Computational modeling correlated dye affinity with observed stability (log PDPPC/PLGA: DiI-2.3, Cou6-0.7).
- In vivo imaging revealed rapid leakage of encapsulated Cou6, while covalently bound Cy5.5 remained localized.
Conclusions:
- The method of dye attachment (encapsulation vs. covalent binding) significantly impacts nanoparticle tracking reliability.
- Encapsulated dyes like coumarin 6 are prone to leakage, potentially leading to false conclusions about nanoparticle penetration.
- Covalently bound dyes provide a more accurate representation of nanoparticle localization, crucial for applications like drug delivery and diagnostics.
