The impact of the design of MoO3 nanorods on the bactericidal performance

Abstract

Our work evaluates the impact of crystallization rate during the synthesis of α-MoO₃ nanorods and their bactericidal performance against Gram (+) S. aureus and Gram (−) E. coli. For this purpose, α-MoO₃ nanorods were synthesized by varying the crystallization times to 12, 24, and 48 h. XRD patterns reveal that crystallization time changes crystal size. The growth of α-MoO₃ does not show chemical modifications. However, SEM and TEM reveal the characteristic nanorods morphology, where the crystallization times affect the diameter. Crystal growth also changes the atomic percentage of Mo/O, which is determined by XPS. The above was reflected in the antibacterial performance of α-MoO₃, evaluated at different nanoparticle concentrations (0.5–4 mg/mL). The α-MoO₃ is an efficacious antibacterial for both pathogens by the enhanced crystal size, with higher bactericidal performance against Gram-positive bacteria, indicating that the rod architecture improves their interaction through electrostatic attraction with the peptidoglycan structure of S. aureus bacteria. In addition, electrochemical measurements indicate that the electroactive area of α-MoO₃ plays a key role in the nanoparticle/bacteria interaction. As a result, the intrinsic characteristics of α-MoO₃ nanorods, including crystal size, morphology, nanorod diameter, oxygen vacancies, and EASA, influence the antibacterial activity, generating materials with potential biomedical applications.