Ibrahim Amar - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya
Shamsi A. Shamsi - Department of Botany (Microbiology Lab), Faculty of Science, Sebha University, Sebha, Libya
Ruqayah Saheem - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya
Amdallah Altawati - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya
Mohammed Abdulkarim - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya
Mabroukah Abdulqadir - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya
Ihssin Abdalsamed - Department of Chemistry, Faculty of Science, Sebha University, Sebha, Libya

Antibiotic-resistant pathogenic bacteria (e.g., multi-drug resistant bacteria, MDR) have been one of the major threats to human health. Nanoparticles, the newly emerging tools, hold the promise to solve the antibiotic resistance-related problems. This study aimed at evaluating the antibacterial activities of Ca-doped ceria nanoparticles (CDC) against the Gram-negative bacteria (Pseudomonas aeruginosa and Klebsiella pneumoniae) and Gram-positive bacteria (Staphylococcus aureus) using optical density measurement. Co-precipitation method was used to synthesize the Ca-doped ceria nanoparticles with and without addition of cetyltrimethylammonium bromide (CTAB, cationic surfactant). The prepared nanoparticles were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy. The XRD results demonstrated that, the CDC-CTAB nanoparticles (synthesized via CTAB-assisted co-precipitation method) had the smaller crystallite size (16.26 nm) and higher specific surface area (56.72 m2/g) compared to the CTAB-free synthesized sample (CDC nanoparticles). In addition, the CDC-CTAB nanoparticles exhibited a better inhibition percentage of bacteria growth (29.54-34.08%) against both the Gram-negative and Gram-positive bacteria. In terms of materials cost and toxicity, Ca-doped ceria nanoparticles can be considered as promising materials and, their biological activity might be evaluated against other microorganisms.

Cerium oxide nanoparticles, Surfactant, Co-precipitation method, Antibacterial Activity, Drug-resistance bacteria, Optical density measurement