Inorganic gold and polymeric poly(lactide-co-glycolide) nanoparticles as novel strategies to ameliorate the biological properties of antimicrobial peptides

Cationic antimicrobial peptides (AMPs) are an interesting class of gene-encoded molecules endowed with a broad-spectrum of anti-infective activity and immunomodulatory properties. They represent promising candidates for the development of new antibiotics, mainly due to their membrane-perturbing mechanism of action that very rarely induces microbial resistance. However, bringing AMPs into clinical field is hampered by some intrinsic limitations, encompassing low peptide bioavailability at the target site and high peptide susceptibility to proteolytic degradation. In this regard, nanotechnologies represent an innovative strategy to circumvent these issues. According to the literature, a large variety of nanoparticulate systems has been employed for drug-delivery, bioimaging, biosensors or as nanoantibiotics. The possibility of conjugating different types of molecules, including AMPs, to these systems, allows the production of nanoformulations able to enhance the biological profile of the compound, while reducing its cytotoxicity and prolonging its residence time. In this mini-review, inorganic gold nanoparticles (NPs) and biodegradable polymeric NPs made of poly(lactide-co-glycolide) are described with particular emphasis on examples of conjugation of AMPs to them, to highlight the great potential of such nanoformulations as alternative antimicrobials.