Photodegradation of Ciprofloxacin-Zinc Complexes Produced at the Interface of ZnO and Cu-Doped ZnO Crystals

Aryane Tofanello,Adrianne M M Brito,Elisângela Belleti,Iseli L Nantes-Cardoso

doi:10.1590/1980-5373-mr-2021-0198

Aryane Tofanello, Adrianne M M Brito + Show 2 more

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https://doi.org/10.1590/1980-5373-mr-2021-0198

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Journal: Materials Research	Publication Date: Jan 1, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Universidade Federal do ABC

Abstract

Abstract Ciprofloxacin hydrochloride (CIPRO) is considered an emerging pollutant in aquatic environments with the capacity to disseminate antibiotic resistance. Considering the pro-oxidant potential of ZnO and Cu-doped ZnO (Cu-ZnO) wurtzite crystals, the potential Ciprofloxacin photodegradation by these materials was investigated. CIPRO titration with ZnO and Cu-ZnO promoted the formation of zinc complexes and ~4% antibiotic adsorption. The carboxylic groups of CIPRO can complex Zn2+ by promoting the nanoetching of ZnO and Cu-ZnO crystallite surfaces. The alkaline interfaces provided by ZnO create a microenvironment favorable for Zn2+ chelation by CIPRO carboxylates. The photodegradation degree was similar for CIPRO and CIPRO-Zn under UV light, as revealed by UV-visible spectroscopy and FTIR. Therefore, the ZnO and Cu-ZnO crystals contributed to the formation of CIPRO-Zn rather than the photo-oxidative degradation of the antibiotic. Considering that CIPRO-Zn chelates disfavor bacterial selection for resistance, the treatment of CIPRO-contaminated effluents with ZnO and Cu-ZnO can facilitate desirable metal chelation without impairing photodegradation.

Highlights

Ciprofloxacin (CIPRO) is a third-generation fluoroquinolone antibiotic that is widely used to treat a broad variety of bacterial infections[1]
The incorporation of copper ions in the precursor solution altered the mechanisms governing the nucleation, growth, and ripening rates of ZnO, and further the incomplete growth of the 1D rods. This may be because the dopant insertion into the reaction environment may have formed new Cu-Zn complexes, which may act as unwanted seeds for the subsequent controlled growth of rice grain-like ZnO microrods
No pronounced peaks corresponding to CuO or Cu2O were observed in the assynthesized Cu-doped ZnO (Cu-ZnO) using the hydrothermal route (Figure 3A, green line), except for the low-intensity diffraction peak at 39.1° belonging to the monoclinic phase CuO indicated by the arrow[38]

Summary

Introduction

Ciprofloxacin (CIPRO) is a third-generation fluoroquinolone antibiotic that is widely used to treat a broad variety of bacterial infections[1]. The occurrence of the intersystem crossing of the singlet electronically excited state of quinolones after light absorption is reported in literature[3,4,5]. Studies of BaniYaseen et al.[6] assigned quinolone moiety as responsible for most of fluoroquinolones properties of absorption and fluorescence spectra. The photoexcitation of CIPRO produces triplet excited states that can trigger reactions leading to photosensitivity in patients undergoing antibiotic treatment[7,8]. The photophysical properties of CIPRO are involved in its photodegradation in diverse environments exposed to light[9,10]. The widespread use of CIPRO has promoted pollution in aquatic environments[11,12,13]

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