Biofilm-Resistant Nanocoatings Based on ZnO Nanoparticles and Linalool.

Vera Alexandra Spirescu,Raluca Șuhan,Laurenţiu Mogoantă,Bogdan Ștefan Vasile,Cornelia Bejenaru,Ludovic Everard Bejenaru,George Dan Mogoşanu,Alexandra Cătălina Bîrcă,Alina Maria Holban,Ovidiu-Cristian Oprea,Irina Negut,Paul Cătălin Balaure,Adelina-Gabriela Niculescu,Valentina Grumezescu,Alexandru Mihai Grumezescu,Ecaterina Andronescu

doi:10.3390/nano11102564

Abstract

Biofilms represent an increasing challenge in the medical practice worldwide, imposing a serious threat to public health. As bacterial strains have developed antibiotic resistance, researcher’s attention has been extensively focused on developing more efficient antimicrobial strategies. In this context, the present study reports the synthesis, physicochemical characterization, ex vivo biodistribution, and in vitro evaluation of the capacity of nanostructured surfaces based on zinc oxide (ZnO) and biologically active molecules to modulate clinically relevant microbial biofilms. ZnO nanoparticles (NPs) were synthesized through a co-precipitation method without thermal treatment. The matrix-assisted pulsed laser evaporation (MAPLE) was applied for preparing nanostructured coatings based on ZnO NPs surface modified with linalool that were further characterized by X-ray diffraction (XRD), thermogravimetric analysis with differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM), transmission electron microscopy with selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FT-IR), and infrared microscopy (IRM). Histological analyses carried out at 7 days and 14 days after the intraperitoneal administration of linalool modified ZnO NPs revealed the absence of the latter from the brain, kidney, liver, lung, myocardium, and pancreas. Through in vitro assays on prokaryotic cells, it was proven that ZnO coatings hinder microbial biofilm formation of both Gram-positive and Gram-negative bacteria strains.

Highlights

A biofilm is a community of bacterial cells embedded in a self-derived extracellular polymeric substance (EPS) matrix attached to a biotic or abiotic surface
X-ray diffraction (XRD) patterns of prepared bare and surface-modified zinc oxide (ZnO) nanoparticles are plotted in Figure 1, respectively
Surface functionalization produces no changes in peak intensities, meaning that the crystalline structure of the nanopowders remains intact

Summary

Introduction

A biofilm is a community of bacterial cells embedded in a self-derived extracellular polymeric substance (EPS) matrix attached to a biotic or abiotic surface. Bacteria exhibit a series of striking features differentiating them from their planktonic freely suspended counterparts. Among these are the reduced growth rate and the altered gene expression. A study carried out recently by the European Centre for Disease Prevention, and Control (ECDC) estimated that 1 in 15 hospital patients acquire at least one healthcare-associated infection (HAI) in European Union (EU) and European Economic Area (EEA) countries daily. A total of 4.5 million HAIs were estimated to occur each year in European hospitals and an additional 4.4 million HAIs in long-term care facilities [8].

Methods

Results

Conclusion