Chemometric and Electrochemical Evaluation of ZnO–Cellulose Composites for Antibacterial and Photocatalytic Applications

The growing concern over antibiotic-resistant bacteria has increased the demand for advanced nanomaterials with antibacterial and photocatalytic properties. Nanostructured zinc oxide (ZnO) is of great interest due to its ability to generate ROS and release Zn²⁺ ions, which underlie its dual functionality. However, its colloidal instability and variable ion release require integrated synthesis and characterization strategies. Here, a two-level factorial Design of Experiments (DoE) was used1 to study the effects of Zn precursor concentration, KCl concentration, and reaction time on material performance2,3. SEM, XRD, and reflectance spectroscopy were used to evaluate morphological and optical properties, while photocatalytic activity was monitored via methylene blue degradation under simulated solar light. Principal Component Analysis (PCA) helped identify optimal synthesis conditions in terms of both photocatalytic efficiency and antibacterial potential against various bacterial strains. To quantify Zn²⁺ ions released into solution, anodic stripping voltammetry (ASV) was employed, supporting the hypothesis that antibacterial activity is linked to Zn²⁺ ion internalization. ZnO was combined into composite materials using cellulose-based supports (ethylcellulose, APTES-functionalized cellulose, microcrystalline cellulose) to further enhance performance4. Electrochemical impedance spectroscopy (EIS) enabled in situ analysis of these supports, revealing surface charge and functionalization degree. Ongoing work focuses on tailoring ZnO surface asymmetry to enable microscale motion for applications in active materials and micro-nano robotics. Financial support from MIUR is acknowledged: grants PRIN 2022 "2022WZK874 - Smart biopolymeric ZnO Nanowires composites for enhanced antibacterial activity (Soteria)", PRJ-1310, CUP: B53D23015730006 and PNRR “Network 4 Energy Sustainable Transition – NEST”, code PE0000021, CUP B73C22001280006, Spoke 1, Mission 4, by EU – NextGenerationEU.