Flame-Made Nanoparticles as Biological Drugs Nanocarriers Towards Effective Treatment of Bacterial Wounds Infections

Antibiotic-resistant bacterial infections have become a significant global concern, particularly in chronic wound cases. The prolonged inflammatory phase in wounds is often attributed to untreated bacterial infections, which impede proper skin healing, lowering patients' quality of life, and contributing to severe complications such as sepsis. This rise in resistance is placing immense burdens on healthcare systems and underscores the urgent need for innovative therapeutic solutions. Antimicrobial biological drugs, known as biologics, offer antibiotic-free alternatives and are being explored as a promising approach to combat this growing threat. Biologics, including peptides and enzymes, are expected to overcome antimicrobial resistance with minimal immunological risks. However, the delivery of biologics in wound sites faces significant challenges, such as their short circulation half-life and susceptibility to environmental factors.

Hybrid nanoformulations (HNs) based on inorganic nanoparticles (NPs) present a cutting-edge solution to these challenges. These nanosystems aim to stabilize and protect biologics from enzymatic degradation, preserving their structural integrity and enhancing their antimicrobial efficacy. By leveraging the unique properties combination of inorganic nanoparticles, such as high surface area and stability, HNs are well-suited to improve biologics drug delivery in infected wounds. Among the inorganic nanoparticles used in nanobiomedical applications, calcium phosphate (CaP) nanoparticles have garnered significant research attention due to their excellent biocompatibility, biodegradability, low toxicity, and tunable immunogenicity. Moreover, CaP NPs promote tissue repair in the injured area responding to the wounded environment by selectively releasing calcium ions.

In this work, we propose a novel approach involving the use of biocompatible CaP nanoparticles synthesized using Flame Spray Pyrolysis. This nanomanufacturing technique enables large-scale production for industrial use while ensuring reproducibility. These CaP NPs are engineered to serve as nanocarriers for biologics, specifically the antimicrobial peptide LL-37 and the enzyme Lysozyme. Both antimicrobial molecules are naturally present in the human body and exhibit high biocompatibility. Lysozyme is particularly effective against Gram-positive bacteria by hydrolyzing the peptidoglycan in their cell walls, while LL-37 exhibits broad-spectrum activity by disrupting bacterial cell membranes.

By forming a hybrid nanoformulation, the CaP NPs ensure the stability of biologics and facilitate their efficient delivery. This research involves optimizing the synthesis parameters, refining the design of the hybrid nanoformulations for biologics stabilization and delivery, and conducting extensive physicochemical characterization. The antimicrobial activity of LL-37 and Lysozyme in the HNs is evaluated both in vitro, using MRSA bacterial cultures, and ex vivo, in fresh human skin samples. This project aims to provide critical insights into the parameters for loading biologics onto CaP nanocarriers and to expedite their translation to clinical applications as therapeutic nanoplatforms.