Porous silicon microparticles as efficient carriers for immunologic adjuvants

In this work we report a first -time combination of porous silicon (pSi) particles with the immunologic adjuvant Pam3CSK4, a TLR 1/2 agonist, as a tool for immunotherapy. pSi is a sponge-like biocompatible and biodegradable nanomaterial with high porosity, large surface-to-volume ratio and tunable surface, suitable for drug delivery applications. This study provides, by means of live-cell confocal microscopy, an insight about the time course of the interaction of free Pam3CSK4 vs vectorized by pSi microparticles with human dendritic cells (DCs). We found a delay in the ingestion of the agonist when carried by pSi microparticles. These findings were supported by the observation of the morphological changes related to the activation of DCs that occurred with a 5 h difference when treated with the vectorized ligand. These results provide the first demonstration of pSi as a conceivable candidate to deliver Pam3CSK4 to DCs paving the way towards immunotherapy practice.