1：Experimental Design and Method Selection:

The study employed a co-precipitation method for synthesizing Mg-doped ZnO nanoparticles (MgZnO NPs) with varying Mg concentrations (x = 0.000, 0.001, 0.003, 0.005, and 0.010 M). This method was chosen for its simplicity, cost-effectiveness, and scalability. Various characterization techniques were used to analyze the properties of the synthesized NPs.

2：000, 001, 003, 005, and 010 M). This method was chosen for its simplicity, cost-effectiveness, and scalability. Various characterization techniques were used to analyze the properties of the synthesized NPs. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples were prepared with specific Mg doping concentrations. Bacterial strain Escherichia coli - DH5α was purchased from the Korean Culture Center of Microorganisms.

3：List of Experimental Equipment and Materials:

Chemicals included zinc nitrate hexahydrate, magnesium nitrate hexahydrate, sodium hydroxide, polyethylene glycol (PEG, Mn 3,350), dimethyl sulfoxide (DMSO), Whatman filter paper (No: 42, pore size = 2.5 μm), ethanol, MacConkey agar, and nutrient broth. Equipment included a TGA 4000 thermogravimetric analyzer, UV–visible spectrophotometer (Shimadzu - UV 2600), FT-IR spectrometer (PerkinElmer Spectrum 65), X-ray diffractometer (Bruker D8 Advance), SEM (Quanta FEG 250), EDS (AMETEK Inc.), XPS instrument (K-Alpha, Thermo Fisher Scientific), TEM (Tecnai G2 Spirit), and electrochemical impedance analyzer (CHI6131D).

4：5 μm), ethanol, MacConkey agar, and nutrient broth. Equipment included a TGA 4000 thermogravimetric analyzer, UV–visible spectrophotometer (Shimadzu - UV 2600), FT-IR spectrometer (PerkinElmer Spectrum 65), X-ray diffractometer (Bruker D8 Advance), SEM (Quanta FEG 250), EDS (AMETEK Inc.), XPS instrument (K-Alpha, Thermo Fisher Scientific), TEM (Tecnai G2 Spirit), and electrochemical impedance analyzer (CHI6131D). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis involved dissolving PEG in distilled water, adding zinc and magnesium nitrate solutions, adding NaOH drop-wise, stirring, heating, washing, grinding, and calcining at 600 °C. Characterization included TGA, UV–vis DRS, FT-IR, XRD, SEM with EDX, XPS, TEM, and cyclic voltammetry. Antibacterial activity was tested via disk diffusion against E. coli under light and dark conditions, with statistical analysis using ANOVA and Tukey's test.

5：Data Analysis Methods:

Data were analyzed using Scherrer's equation for crystallite size, UV–vis DRS for band gap calculation, and statistical methods (mean ± SE, ANOVA, Tukey's HSD test) for antibacterial activity.