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

초록

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 ZrO2 NPs for improved antibacterial activity. The preparation of TCH-ZrO2 NPs consisted of two steps; (i) biogenic synthesis of ZrO2 NPs using L. rhamnosus GG, and (ii) loading the TCH on ZrO2 NPs through an absorption mechanism. The strong absorption peak at 282 nm in UV spectrophotometric spectrum indicated the synthesis of ZrO2 NPs. The ZrO2 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 ZrO2 NPs and a z-average size of 186.00 +/- 0.57 d.nm with a PDI of 0.190 for TCH-ZrO2 NPs. Furthermore, the zeta potential was 12.54 +/- 0.89 mV for TCH,-31.2 +/- 1.2 mV for ZrO2 NPs and 29.32 +/- 2.15 mV for TCH-ZrO2 NPs. XRD results confirmed the tetragonal and monoclinic phase of synthesized ZrO2 NPs. The FTIR spectrum evidenced the overlapping of vibrational bonds from the TCH to TCH-ZrO2 NPs. The ZrO2 NPs and TCH-ZrO2 NPs did not exhibit significant cytotoxicity in the HEK293 cell line. Furthermore, both ZrO2 NPs and TCH-ZrO2 NPs did not induce hemolysis and/or damage in egg CAM. TCH-ZrO2 NPs exhibited the MIC and MBC were 7.81 mu g/mL and 250.15 mu g/mL for S. entrica while 7.85 and 500.17 for S. aureus respectively. Among the samples, the TCH-ZrO2 NPs exhibited a strong bio-film eradication activity. These results prove that the loading of the TCH in ZrO2 NPs reduces the toxicity of the TCH and improves its antibacterial efficiency.

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