Development of Polythiourethane/ZnO-Based Anti-Fouling Materials and Evaluation of the Adhesion of Staphylococcus aureus and Candida glabrata Using Single-Cell Force Spectroscopy.

Sophie Klemm,Haoyi Qiu,Claire Tendero,Anna Gapeeva,Rainer Adelung,Mickaël Castelain,Zibin Nan,Martina Baum,Miguel Cacho Teixeira,Etienne Dague,Cécile Formosa-Dague,Mafalda Cavalheiro

doi:10.3390/nano11020271

Abstract

The attachment of bacteria and other microbes to natural and artificial surfaces leads to the development of biofilms, which can further cause nosocomial infections. Thus, an important field of research is the development of new materials capable of preventing the initial adhesion of pathogenic microorganisms. In this work, novel polymer/particle composite materials, based on a polythiourethane (PTU) matrix and either spherical (s-ZnO) or tetrapodal (t-ZnO) shaped ZnO fillers, were developed and characterized with respect to their mechanical, chemical and surface properties. To then evaluate their potential as anti-fouling surfaces, the adhesion of two different pathogenic microorganism species, Staphylococcus aureus and Candida glabrata, was studied using atomic force microscopy (AFM). Our results show that the adhesion of both S. aureus and C. glabrata to PTU and PTU/ZnO is decreased compared to a model surface polydimethylsiloxane (PDMS). It was furthermore found that the amount of both s-ZnO and t-ZnO filler had a direct influence on the adhesion of S. aureus, as increasing amounts of ZnO particles resulted in reduced adhesion of the cells. For both microorganisms, material composites with 5 wt.% of t-ZnO particles showed the greatest potential for anti-fouling with significantly decreased adhesion of cells. Altogether, both pathogens exhibit a reduced capacity to adhere to the newly developed nanomaterials used in this study, thus showing their potential for bio-medical applications.

Highlights

Hospital-acquired microbial infections, called nosocomial infections, are nowadays a leading cause of death on all continents [1]
Our analyses show that PTU/ZnO composites have a decreased roughness compared to PDMS, an increased stiffness, they have a lower Water Contact Angle (WCA) and are hydrophilic, and they present a more negatively charged surface
We demonstrate the development and characterization of new anti-fouling materials based on PTU filled with ZnO particles

Summary

Introduction

Hospital-acquired microbial infections, called nosocomial infections, are nowadays a leading cause of death on all continents [1]. Such infections are often caused by pathogenic bacteria and yeast, which are able to form biofilms on medical devices such as catheters, pacemakers or prosthetic joints. It is followed by a transition from reversible to irreversible microbial adhesion where physico-chemical bonds are strengthened [5] and chemical forces, such as hydrophobic or hydrophilic forces [6], can be involved After these adhesion steps, cells undergo important changes (cell wall deformation, production of exopolysaccharides, gene expression etc.) that lead to the formation of a mature biofilm [5]

Methods

Results

Conclusion