Superior visible light antimicrobial performance of facet engineered cobalt doped TiO2 mesocrystals in pathogenic bacterium and fungi

Ayat N El-Shazly,Mahmoud A Hamza,Nageh K Allam,Aiat H Hegazy,E T El Shenawy,Rasha M Fathy,Gharieb S El-Sayyad

doi:10.1038/s41598-021-84989-x

Abstract

Pristine and Co-doped TiO2 mesocrystals have been synthesized via a simple sol–gel method and their antimicrobial activity has been investigated. The antimicrobial performance was evaluated in terms of zone of inhibition, minimum inhibitory concentration (MIC), antibiofilm activity, and effect of UV illumination in liquid media. The Co-doped TiO2 mesocrystals showed very promising MIC of 0.390 μg/mL and 0.781 μg/mL for P. mirabilis and P. mirabilis, respectively. Additionally, the material showed an MIC of 12.5 μg/mL against C. albicans, suggesting its use as antifungal agent. Upon the addition of 10.0 µg/mL of Co-doped TiO2 mesocrystals, the biofilm inhibition% reaches 84.43% for P. aeruginosa, 78.58% for P. mirabilis, and 77.81% for S. typhi, which can be ascribed to the created active oxygen species that decompose the tested microbial cells upon illumination. Thus the fabricated Co-doped TiO2 mesocrystals exhibit sufficient antimicrobial features under visible light, qualifying them for use as antimicrobial agents against pathogenic bacteria and fungi and subsequently inhibit their hazardous effects.

Highlights

Pristine and Co-doped TiO2 mesocrystals have been synthesized via a simple sol–gel method and their antimicrobial activity has been investigated
No diffraction peaks for cobalt or cobalt oxide were detected in the Co-doped T iO2 sample, which may be related to the low cobalt content[33]
Unique multi-doped T iO2 mesocrystals have been synthesized via a facile sol–gel approach

Summary

Introduction

Pristine and Co-doped TiO2 mesocrystals have been synthesized via a simple sol–gel method and their antimicrobial activity has been investigated. Mesocrystals were proposed to form upon the addition of highly oriented small particles, the resulting larger crystals would have single-crystal orientation[4] Their positive effects in improving charge carriers separation made them good candidates for many applications, such as photocatalysis[5], sensing, and energy storage and conversion[6]. Upon irradiated by UV light, the anatase phase of T iO2 can oxidize and reduce oxygen and water to produce reactive oxygen species (ROS), such as superoxide radicals and hydroxyl radicals[11] These ROS play a key role in destroying pathogenic bacteria and fungi by damaging their critical molecular components[12,13]. Bandgap, enhancing the concentration of reactive radical s pecies[25], and enhancing visible light absorption[24] In this regard, identifying a one-step synthesis method of multi-doped T iO2 is extremely desirable, which remains a challenge to be realized. The innovative points of this research include the one-pot synthesis with controlled amount of dopants, the defective structures and how defects played a role in the antibacterial properties as well as the superior dual bacterial and fungi inhibition functions

Methods

Results

Conclusion