Layer-by-layer assembly of poly(lactic acid) nanoparticles: a facile way to fabricate films for model drug delivery.

Layer-by-layer (LBL) films of poly(lactic acid) nanoparticles (PLA NPs) and poly(ethyleneimine) (PEI) were fabricated as a novel drug-delivery system. The PLA NPs, which encapsulated pyrene as a model drug, were prepared by nanoprecipitation methods. The assembly process of PLA NPs/PEI LBL films was monitored by UV-vis spectroscopy, and the load of pyrene in the multilayer films was verified by fluorescence spectroscopy. The morphology of the PLA NPs/PEI LBL films was observed by SEM. The release profile of pyrene from the LBL films in PBS solutions was further studied, and the result indicated that the PLA NPs/PEI films were capable of sustainably releasing pyrene as expected. The fabrication of PLA NPs/PEI LBL films provides a new facile method for drug delivery and paves the way for loading multiple types of drugs into a single LBL film.