Antimicrobial peptides (AMPs) have recently gained attention as a viable solution for combatting antibiotic resistance due to their numerous advantages, including their broad-spectrum activity, low propensity for inducing resistance, and low cytotoxicity. Unfortunately, their clinical application is limited due to their short half-life and susceptibility to proteolytic cleavage by serum proteases. Indeed, several chemical strategies, such as peptide cyclization, N-methylation, PEGylation, glycosylation, and lipidation, are widely used for overcoming these issues. This review describes how lipidation and glycosylation are commonly used to increase AMPs’ efficacy and engineer novel AMP-based delivery systems. The glycosylation of AMPs, which involves the conjugation of sugar moieties such as glucose and N-acetyl galactosamine, modulates their pharmacokinetic and pharmacodynamic properties, improves their antimicrobial activity, and reduces their interaction with mammalian cells, thereby increasing selectivity toward bacterial membranes. In the same way, lipidation of AMPs, which involves the covalent addition of fatty acids, has a significant impact on their therapeutic index by influencing their physicochemical properties and interaction with bacterial and mammalian membranes. This review highlights the possibility of using glycosylation and lipidation strategies to increase the efficacy and activity of conventional AMPs.

Chronic lung infections in cystic fibrosis (CF) patients are triggered by multidrug-resistant bacteria such as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Stenotrophomonas maltophilia. The CF airways are considered ideal sites for the colonization and growth of bacteria and fungi that favor the formation of mixed biofilms that are difficult to treat. The inefficacy of traditional antibiotics reinforces the need to find novel molecules able to fight these chronic infections. Antimicrobial peptides (AMPs) represent a promising alternative for their antimicrobial, anti-inflammatory, and immunomodulatory activities. We developed a more serum-stable version of the peptide WMR (WMR-4) and investigated its ability to inhibit and eradicate C. albicans, S. maltophilia, and A. xylosoxidans biofilms in both in vitro and in vivo studies. Our results suggest that the peptide is able better to inhibit than to eradicate both mono and dual-species biofilms, which is further confirmed by the downregulation of some genes involved in biofilm formation or in quorum-sensing signaling. Biophysical data help to elucidate its mode of action, showing a strong interaction of WMR-4 with lipopolysaccharide (LPS) and its insertion in liposomes mimicking Gram-negative and Candida membranes. Our results support the promising therapeutic application of AMPs in the treatment of mono- and dual-species biofilms during chronic infections in CF patients.

Numerous supramolecular platforms inspired by natural self-assembly are exploited as drug delivery systems. The spontaneous arrangement of single building blocks into inorganic and organic structures is determined and controlled by noncovalent forces such as electrostatic interactions, π-π interactions, hydrogen bonds, and van der Waals interactions. This review describes the main structures and characteristics of several building blocks used to obtain stable, self-assembling nanostructures tailored for numerous biological applications. Owing to their versatility, biocompatibility, and controllability, these nanostructures find application in diverse fields ranging from drug/gene delivery, theranostics, tissue engineering, and nanoelectronics. Herein, we described the different approaches used to design and functionalize these nanomaterials to obtain selective drug delivery in a specific disease. In particular, the review highlights the efficiency of these supramolecular structures in applications related to infectious diseases and cancer.

Antimicrobial peptides (AMPs) represent a powerful support to conventional antibiotics in addressing the global challenge of antimicrobial resistance (AMR). Their broad-spectrum antimicrobial activity and unique mechanisms of action enable diverse potential applications, including combating multidrug-resistant pathogens, immune modulation, and cancer therapy. Their clinical implementation is hindered by challenges such as toxicity, instability, and high production costs. Recent advances in AMP design, optimization, and delivery mechanisms such as nanoparticle conjugation and rational engineering have enhanced their efficacy, stability, and specificity. Integrating AMPs into precision medicine and combining them with existing therapies promises to overcome current limitations. With ongoing advancements, AMPs have the potential to redefine infection management and possibly other medical problems.

Innovative drug delivery platforms are redefining the landscape of modern therapeutics, from dendrimers and liposomes to polymeric systems and metallic nanoparticles. The development of carrier systems that combine safety, biocompatibility and therapeutic efficacy is being focused upon in research. In this study, we designed and functionalised liposomes for the delivery of small interfering RNA (siRNA) that specifically targets and silences EGFR in triple-negative breast cancer (TNBC) cells characterized by EGFR overexpression. DOPE/TAP/R9-based liposomes conjugated with therapeutic siRNA directed against EGFR were investigated to assess their potential as a targeted delivery platform. The study focused on evaluating the biophysical properties of liposome:siEGFR complexes, intracellular trafficking capacity and effective change in EGFR expression at the gene and protein level. A suite of analytical techniques, including fluorescence polarisation, circular dichroism, dynamic light scattering, ζ-potential measurements, gel retardation assays and electrophoresis in the presence of nucleases, demonstrated that DOPE/TAP/R9-Chol liposomes form stable and protective complexes with siRNA. Subsequent cellular uptake studies, using flow cytometry and confocal microscopy, confirmed that there was efficient intracellular delivery into the MDA-MB-231 cell line and RT-PCR and western blot proved the effectiveness of gene silencing by transported siRNA. The results identified an optimal liposome:siRNA formulation and mark a promising step toward the development of a safe and effective siRNA delivery system for biomedical applications.

Understanding the physicochemical factors that govern siRNA nanocarrier assembly is essential for the rational design of effective delivery systems. By optimizing various lipid compositions, cholesterol content and PEG length we created a peptide-functionalized cationic liposomal platform made of DOPE/TAP lipids with cholesterol-anchored nona-arginine (R9-Chol) for siRNA complexation, intracellular transport and effective silencing of the target EGFR gene. Analysis of ζ-potential and dynamic light scattering allowed to rationally design formulation of stable, monodisperse nanoscale lipoplexes with a positive surface charge. With fluorescence polarization, circular dichroism and agarose gel electrophoresis we found an optimal siRNA:liposome complexation ratio of 1:77, which protected siRNA from ribonuclease-mediated degradation. Morphological imaging confirmed a shift from discrete vesicular structures to organized multilamellar lipoplexes, consistent with electrostatically driven self-assembly. In cellular studies, the optimized nanocarrier promoted efficient uptake of fluorescent siRNA in MDA-MB-231 cells and achieved functional delivery of anti-EGFR, leading to substantially reduced expression of the target gene at both transcript and protein levels. This work offers mechanistic understanding of peptide-assisted lipid:siRNA assembly and positions R9-functionalized DOPE/TAP liposomes as a promising platform for siRNA delivery.