Protein Encapsulation into PLGA Nanoparticles by a Novel Phase Separation Method Using Non-Toxic Solvents

Nanoparticles of biocompatible and biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) are widely used as drug delivery systems for the administration of biomolecules like proteins. The purpose of this work is to validate a novel formulation method by a phase separation phenomenon using the non-toxic solvent glycofurol (GF) in order to encapsulate proteins into PLGA nanoparticles. Nanoprecipitates of a model protein (lysozyme) and a therapeutic protein (TGF-β1) were formed to ensure their stability upon subsequent encapsulation into PLGA nanoparticles. Good encapsulation efficiency was obtained with preservation of the structure integrity and protein bioactivity after encapsulation. PLGA nanoparticles were then characterized in terms of size, zeta potential and morphology. Moreover, residual solvent was quantified and in vitro release study of the encapsulated proteins was performed to demonstrate the efficacy of our encapsulation method in drug sustained release. Finally, cytocompatibility study of nanoparticles was performed. Thus, we developed an effective method based on the preliminary step of protein precipitation for the formulation of PLGA nanoparticles as protein carriers for biomedical applications. PLGA nanoparticles by a novel phase separation method called nanoprecipitation using glycofurol as polymer solvent [38]. In the present work, in addition to the encapsulation of lysozyme as a model protein, TGF-β1 was chosen to be loaded into these nanoparticles due to its important role in cell proliferation, differentiation and extracellular matrix metabolism [43]. Therefore, controlled release of TGF-β1 might be of great interest in cartilage tissue engineering [44,45]. Proteins were firstly precipitated using GF or a mixture of GF and DMI to ensure their stability and were then encapsulated into the nanoparticles. Physicochemical properties of these nanoparticles were investigated and solvent residual content was quantified. Moreover, different techniques were performed to confirm the protein integrity and bioactivity upon the encapsulation. Besides, in vitro release of the proteins from PLGA nanoparticles was presented to ensure the utility of these carriers in drug sustained release. Furthermore, cytotoxicity of nanoparticles was assessed as preliminary evaluation of the cytocompatibility of these systems which will be used in cartilage tissue engineering application. This work is involved in a global project which aims to conceive novel biomaterials composed of implantable synthetic extracellular matrices combined with TGF-β1-loaded particles for cartilage regeneration. However, the application of obtained polymeric systems might be extended to any domain requiring protein encapsulation. Materials and Methods Materials Lysozyme (14 kDa) from chicken egg-white, Micrococcus Citation: Swed A, Cordonnier T, Fleury F, Boury F (2014) Protein Encapsulation into PLGA Nanoparticles by a Novel Phase Separation Method Using Non-Toxic Solvents. J Nanomed Nanotechnol 5: 241. doi: 10.4172/2157-7439.1000241