Cyclodextrins in metal oxide nanoparticles (NPs) serve as stabilizing, dispersing, and functionalizing agents that enhance antimicrobial performance through better nanoparticle stability, synergistic action, and potential controlled release mechanisms, making them ideal for advanced biomedical and environmental antimicrobial applications. In this study, NPs of vanadium pentoxide (V₂O₅) were obtained by the precipitation method, and, following a supramolecular assembly, were synthesized using the impregnation method via addition of β-cyclodextrin (BCD) and its derivatives, such as hydroxypropyl-β-cyclodextrin (HCD) and methyl-β-cyclodextrin (MCD). The formation of the V₂O₅:CDs was driven by non-covalent host–guest interactions, leading to a stable supramolecular structure with enhanced physicochemical properties. Morphological analysis using scanning electron microscopy (SEM) revealed uniformly distributed V₂O₅ NPs within the CD matrix. Structural characterization was further supported by proton nuclear magnetic resonance (NMR) spectroscopy, which confirmed the inclusion interactions between V₂O₅ and CDs. The synthesized NPs demonstrated significant antimicrobial activity against Gram-positive and fungal strains, indicating a synergistic enhancement in bioactivity due to the supramolecular architecture. This work highlights the potential of CD-assisted V₂O₅ NPs as promising antimicrobial agents for biomedical and environmental applications.

The electrochromic (EC) behavior of tungsten oxide (WO₃) is strongly influenced by its nanoscale architecture and local chemical environment, which determine the efficiency of ion–electron transport during switching. Here, a systematic polyvinylpyrrolidone (PVP)–Manganese (Mn) synergistic engineering approach was developed using bare WO₃ (WO), PVP-assisted WO₃ (P-WO), Mn-doped WO₃ (Mn-WO), and PVP-assisted Mn-doped WO₃ (P-Mn-WO) to clarify the individual and combined effects of PVP and Mn on EC performance. All films retained the amorphous WO₃ structure, while morphological evolution revealed a transition from compact nanoparticle assemblies to an interconnected porous architecture in P-Mn-WO. The optimized P-Mn-WO film exhibited enhanced Li⁺ transport, with diffusion coefficients of 0.45 × 10⁻¹⁰ and 4.08 × 10⁻¹⁰ cm²/s for oxidation and reduction, respectively. This favorable transport environment enabled 75.8% optical modulation at 635 nm, a coloration efficiency of 142.63 cm²/C, and 92.59% charge reversibility, with only 5.24% degradation during repeated switching. At the device level, P-Mn-WO delivered 82.30% bleached transmittance, 12.02% colored transmittance, and 70.28% optical modulation, while showing only 4.5% degradation over 2000 s of continuous operation. These results demonstrate that coupling PVP-assisted growth with Mn doping provides effective control over WO₃ morphology, Li⁺ transport, charge utilization, and optical switching, establishing a promising route toward a durable, high-contrast WO₃-based EC smart-window.