Comparative Study of Physicochemical and Antibacterial Properties of ZnO Nanoparticles Prepared by Laser Ablation of Zn Target in Water and Air.

Ekaterina A Gavrilenko,Anna L Nemoykina,Ivan N Lapin,Sergei A Kulinich,Ali A Aljulaih,Valery A Svetlichnyi,Daria A Goncharova,Neli Mintcheva

doi:10.3390/ma12010186

Abstract

Here, we report on ZnO nanoparticles (NPs) generated by nanosecond pulsed laser (Nd:YAG, 1064 nm) through ablation of metallic Zn target in water and air and their comparative analysis as potential nanomaterials for biomedical applications. The prepared nanomaterials were carefully characterized in terms of their structure, composition, morphology and defects. It was found that in addition to the main wurtzite ZnO phase, which is conventionally prepared and reported by others, the sample laser generated in air also contained some amount of monoclinic zinc hydroxynitrate. Both nanomaterials were then used to modify model wound dressings based on biodegradable poly l-lactic acid. The as-prepared model dressings were tested as biomedical materials with bactericidal properties towards S. aureus and E. coli strains. The advantages of the NPs prepared in air over their counterparts generated in water found in this work are discussed.

Highlights

Because of their unique physicochemical properties, nanomaterials have recently attracted a lot of research interest as materials and components for various applications
This is consistent with previous reports on Zinc oxide (ZnO) NPs prepared via pulsed laser ablation (PLA) in liquids [5,6,10,15,16], confirming that highly active Zn species generated by laser pulse react with oxygen and/or water molecules, giving rise to ZnO nanomaterial
This observation is in agreement with previous studies as small amounts of metallic phase inclusion was previously reported by different groups for various ZnO NPs produced in liquids [6,14,16]

Summary

Introduction

Because of their unique physicochemical properties, nanomaterials have recently attracted a lot of research interest as materials and components for various applications. One attractive method to produce so-called “pure” ZnO nanostructures (i.e., with surface free of any impurities or stabilizers) for biomedical use is based on pulsed laser ablation (PLA) of metallic Zn target in different media (mainly in liquids) [4,5,6,7,8,9,10]. The method uses pulsed lasers (with different pulse energy and pulse width) to ablate zinc target and produce species which react with the surrounding liquid and form ZnO NPs. The formation mechanisms are quite complex, depending on laser pulse parameters and composition of liquid medium, and involve several fast stages that overlap and compete with each other, such as: absorption of irradiation, melting and evaporation on the target, expansion of the formed plasma/vapor, chemical reactions and quenching by the liquid, formation of clusters and primary NPs, and secondary irradiation of the formed NPs by laser beam, just to name the main ones.

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Conclusion