Biodegradable Near-Infrared Fluorescent Nanobiomarkers: Preparation, Characterization and In-Vitro Release
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 stable, biodegradable, biocompatible, and nontoxic near infrared fluorescent nanobiomarkers. Various formulations of poly(dl-lactic-co-glycolic acid) (PLGA) nanoparticles were engineered to efficiently entrap near-infrared fluorescent dye Indocyanine green (ICG) and characterized to achieve an optimum formulation. In-vitro release profiles of nanoparticles were determined.
PLGA nanoparticles entrapping ICG were prepared by a modified spontaneous emulsification solvent diffusion method. In an attempt to optimize the nanoparticle formulation, the influence of formulation parameters such as amount of ICG and polymer used during preparation were investigated. The ICG entrapment in nanoparticles, nanoparticle size and zeta potential were determined. Atomic Force Microscopy (AFM) was used for surface characterization and release of ICG from nanoparticles was determined by a new continuous fluorescence monitoring technique.
All PLGA nanoparticles formulations were found to have the mean diameter within the range of 300 nm to 410 nm and ICG entrapment up to 74%. All nanoparticles formulation were found to have almost similar ICG content and showed increase in ICG entrapment with increase in amount of polymer. AFM images indicate that the nanoparticles are almost spherical in shape and have numerous pores on their surface. The release pattern consists of an initial release phase releasing 60% of ICG (within 7-8 hrs) followed by a relatively slow release phase.
Efficient entrapment of ICG in PLGA nanoparticles (74 %) was obtained and optimum formulation parameters were determined. The increase in the amount of polymer in the formulation leads to higher ICG entrapment. Nanoparticles formed were spherical and had porous surface and exhibit the characteristic release pattern of a monolithic matrix based system.