Tetracycline-loaded zirconium oxide nanoparticles synthesized by Lactobacillus rhamnosus effectively eradicate bacterial biofilms

Abstract

• Zirconium oxide nanoparticles (ZrO 2 NPs) were synthesized using the Lactobacillus rhamnosus. • ZrO 2 NPs were used as a carrier to improve the antibacterial activity of tetracycline (TCH). • TCH-loaded ZrO 2 NPs exhibited promising antibacterial and biofilm eradication activity. • TCH- ZrO 2 NPs did not show the toxicity in egg-CAM and RBC. The increase of drug-resistant bacterial populations causes a serious disaster in human beings. Also, improving the therapeutic efficiency of antibiotics without adverse effects is required. Hence, the present work prepared and characterized the tetracycline-loaded, Lactobacillus rhamnosus GG extract mediated ZrO 2 NPs for improved antibacterial activity. The preparation of TCH- ZrO 2 NPs consisted of two steps; (i) biogenic synthesis of ZrO 2 NPs using L. rhamnosus GG, and (ii) loading the TCH on ZrO 2 NPs through an absorption mechanism. The strong absorption peak at 282 nm in UV spectrophotometric spectrum indicated the synthesis of ZrO 2 NPs. The ZrO 2 NPs found to be polydisperse, amorphous-structured small pebbles, sized < 50 nm with the presence of Zr, O, C, and N indicated by FE-TEM and EDS analysis. The DLS analysis revealed the z-average size of 115.0 ± 1.23 d.nm with a PDI of 0.221 for ZrO 2 NPs and a z-average size of 186.00 ± 0.57 d.nm with a PDI of 0.190 for TCH-ZrO 2 NPs. Furthermore, the zeta potential was 12.54 ± 0.89 mV for TCH, −31.2 ± 1.2 mV for ZrO 2 NPs and 29.32 ± 2.15 mV for TCH-ZrO 2 NPs. XRD results confirmed the tetragonal and monoclinic phase of synthesized ZrO 2 NPs. The FTIR spectrum evidenced the overlapping of vibrational bonds from the TCH to TCH-ZrO 2 NPs. The ZrO 2 NPs and TCH-ZrO 2 NPs did not exhibit significant cytotoxicity in the HEK293 cell line. Furthermore, both ZrO 2 NPs and TCH-ZrO 2 NPs did not induce hemolysis and/or damage in egg CAM. TCH-ZrO 2 NPs exhibited the MIC and MBC were 7.81 μg/mL and 250.15 μg/mL for S. entrica while 7.85 and 500.17 for S. aureus respectively. Among the samples, the TCH-ZrO 2 NPs exhibited a strong bio-film eradication activity. These results prove that the loading of the TCH in ZrO 2 NPs reduces the toxicity of the TCH and improves its antibacterial efficiency.