Formulation, characterization and cytocompatibility evaluation of novel core-shell solid lipid nanoparticles for the controlled and tunable delivery of a model protein

Lipid-based carriers have been extensively explored in the pharmaceutical industry showing superior advantages for topical applications over conventional colloidal carriers. Indeed, solid lipid nanoparticles (SLN) are effective carriers for the delivery of proteins or peptides. Yet, a system with high protein encapsulation capacity and sustained release profile remains a challenge. Herein, a hybrid release-controlled delivery system consisting of a suspension of core-shell nanocapsules was prepared. The nanocapsules are composed cationic SLN core and a bi-layered shell constructed via the layer-by-layer self-assembly of alternate coats of anionic alginate (AL) and cationic chitosan (CH). Compact, spherical, monodisperse, cytocompatible and stable SLN (AL- CH) nanocapsules (<150 nm) resulted. High cargo loading accompanied with modulated release of load (bovine serum albumin, as a model protein) dosages is demonstrated. The system offers compartments for protein entrapment including core and within the polyelectrolyte layers of shell. To the best of our knowledge, this is the first report describing the step-wise build-up of a tunable polymeric shell on a SLN core.