Antimicrobial photodynamic inactivation (aPDI) represents a promising alternative strategy for combating bacterial infections. This study investigates the potential of curcumin-loaded chitosan nanoparticles (CurChNPs) as novel nanoenabled photosensitizer agents for bacterial photoinactivation. CurChNPs were synthesized using an innovative dual synthesis approach by combination of nanoprecipitation and ionic gelation methods; their physicochemical properties were also characterized. The nanoparticles exhibited excellent solubility in aqueous solutions, high curcumin encapsulation efficiency (96%), and controlled release profile. Photoinactivation assays were conducted against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) to evaluate the efficacy of CurChNPs in aPDI. The nanoparticles exhibited significant photobactericidal activity when irradiated with blue light (450 nm, 28.84 mW·cm^-2). Mechanistic studies confirmed the generation of reactive oxygen species (ROS) as the primary mode of photoinactivation. Microscopy analyses revealed structural damage to bacterial cell membranes, culminating in cell lysis. These findings highlight the synergistic effects of the photodynamic activity of curcumin and the antimicrobial activity of chitosan, demonstrating that CurChNPs are a promising platform for the eradication of bacterial infections. This work contributes to the development of sustainable, nanotechnology-based approaches for addressing bacterial infections, particularly against resilient Gram-negative pathogens. Future studies may explore the potential of CurChNPs against antibiotic-resistant bacterial strains.

The aim of this work was to investigate the potential of a new 3,6-O,O'-dimyristoyl derivative amphiphilic chitosan (DMCh), in improving the solubility of camptothecin (CPT), a hydrophobic anticancer drug, and its potential oral delivery. FTIR, 1H NMR and solid-state 13C NMR spectroscopy were used to characterize DMCh and to determine its average degree of substitution (DS¯=6.8%). DMCh/CPT micelles size ranged from (281-357nm), zeta potential (+32-50mV) of encapsulation efficiency of 42-100%. The in vitro cell viability showed that DMCh/CPT micelles were able to reduce the toxicity of CPT. The in vitro permeability of CPT through Caco-2 and Caco-2/HT29-MTX intestinal models was increased up to ten fold when formulated into DMCh micelles, underlining the mucoadhesive properties of the nanocarrier. DMCh/CPT micelles are able to enhance CPT solubility and bioavailability while reduce its cytotoxicity, showing the great potential for intestinal delivery of hydrophobic drugs.