Antibacterial Effect of 405 nm Diode Laser and the Shape of Silver Nanoparticles on Escherichia coli

Background: Silver nanoparticles (Ag-NPs) have gained significant attention for their unique properties and potential applications, particularly in the field of antibacterial activity. The synthesis of Ag-NPs through the laser ablation method in liquid allows for the production of different shapes, influencing their optical and biological properties. Objectives: The present study was aimed amount-dependent effects of different Ag-NP shapes on Escherichia coli . The evaluation of the impact of irradiation on the antibacterial activity of Ag-NPs was conducted by using a 405 nm laser. Materials and Methods: Laser ablation method in liquid was used to prepare Ag-NPs with varying shapes. Optical property analysis: UV–vis spectroscopy was performed to examine the optical properties of the synthesized Ag-NPs. Dynamic light scattering and transmission electron microscopy were employed to determine the size and morphology of the Ag-NPs. The impact of Ag-NPs on E. coli was studied, considering both concentration and shape dependencies. The antibacterial activity of irradiated and nonirradiated Ag-NPs was compared. Results: The results of the study revealed the following key findings. Shape dependency: the antibacterial activity of Ag-NPs was found to be shape-dependent, with rod-shaped Ag-NPs exhibiting complete inhibition of E. coli at a lower concentration (0.1 mL) compared to spherical-shaped Ag-NPs (1 mL). Irradiation effect: irradiated Ag-NPs using a 405 nm laser at 20 mW demonstrated higher antibacterial activity than their nonirradiated counterparts. Conclusions: This study explores the antibacterial potential of Ag-NPs and silver nanorods (Ag-NRs) against E. coli bacteria. Notably, the antibacterial efficacy is significantly heightened through the irradiation of Ag-NPs by a laser beam with a wavelength of 405 nm. Comparative analysis reveals that Ag-NPs exhibit superior antibacterial activity when compared to Ag-NRs against E. coli .