Enhanced Intracellular Uptake of Indocyanine Green by Incorporation into Polymeric Nanoparticles
Vishal Saxena, Drug Delivery & Biotechnology Laboratory, College of Pharmacy and Health Sciences
Mostafa Sadoqi, Department of Physics, St. John’s College of Liberal Arts and Sciences
Jun Shao, Department of Pharmacy and Administrative Sciences, College of Pharmacy and Health Sciences
The objective of this study is to develop a biodegradable, biocompatible, nontoxic and targetable third generation photosensitizer. For this poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles were engineered by entrapping near-infrared photodynamic agent, Indocyanine green (ICG) and the intracellular uptake and cytotoxicity of these nanoparticles were evaluated.
PLGA (50:50) nanoparticles entrapping ICG were prepared by a modified spontaneous emulsification solvent diffusion method. The ICG entrapment in nanoparticles was determined and physicochemical characterization of nanoparticles was performed. The intracellular uptake and cytotoxicity of these nanoparticles was evaluated on C-33A cervix carcinoma cell line in comparison with the free drug. The influence of drug concentration was investigated for uptake efficiency and cytotoxicity.
PLGA nanoparticles with mean diameter of 357 ~ 21 nm and ICG entrapment of about 74% were obtained. With both ICG formulations tested, the ICG intracellular uptake increased cell with increasing concentration. The enhanced ICG uptake of nanoparticles compared to free drug was prominent at drug concentrations up to 0.022 ~M. The cytotoxicity with ICG solution showed no cytotoxicity up to 50 ~M concentrations. The nanoparticles formulation also showed no evident cytotoxicity for the concentrations studied.
This investigation demonstrated that the encapsulation of ICG into nanoparticles should be considered as an effective strategy for delivering ICG to tumor cells. The efficient intracellular ICG uptake and no cytotoxicity by these formulations indicate their potential for imaging and photo-sensitizing purposes.