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Antimicrobial properties of Ag+ loaded zeolite polyester polyurethane and silicone rubber and long-term properties after exposure to in-vitro ageing
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.ORCID iD: 0000-0002-2139-7460
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
Department of Polymer Engineering, University of Miskolc.
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2010 (English)In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 95, no 9, 1456-1465 p.Article in journal (Refereed) Published
Abstract [en]

In biomedical applications, tubes (e.g. catheters etc.) are commonly produced from polyurethane (PU) and silicone rubber which are known to be biocompatible materials. Several studies have shown that tubes, which are connected to the body (invasive) (especially urinary, tracheotomy and central venous catheters) are associated with infections. The present study reports the development of a new method aiming at obtaining antibacterial properties for PU and silicone rubber by mixing respective material with a natural antibacterial agent (Ag+ loaded zeolite) in different weight fractions. The influence of the zeolite content on the antimicrobial properties were analysed by exposure to bacteria (ISO 22196) and mixtures of fungi (ISO 846). The materials were also subject to artificial body fluids (Artificial Lysosomal Fluid (ALF) and Gamble's solution) for periods up to three months and the subsequent changes in the chemical properties after in-vitro exposure were determined by Matrix Assisted Laser Deposition/Ionization Time Of Flight Mass Spectrometry (MALDI-TOF MS) and Attenuated Total Reflection Fourier Transform Infra Red spectroscopy (ATR-FTIR). It was established that the antimicrobial effect of the materials increased with the increase of the zeolite content. The wettability of the materials was found to decrease significantly during the in-vitro exposure, but this could not be correlated to the zeolite content. In the PU samples, the formation of free carbonyl and -OH groups was observed, which corresponds to oxidative degradation. In case of the silicone rubber the ratio of cyclic PDMS to linear PDMS (H, CH3 and dimethyl terminated) decreased, which indicates a change in the concentration of the compounds. The formation and increase of the O-H bond during the exposure was also confirmed by the infrared spectra of the material which corresponds to hydrolysis of the silicone rubber.

Place, publisher, year, edition, pages
2010. Vol. 95, no 9, 1456-1465 p.
Keyword [en]
Degradation, In-vitro, Silver zeolite, Antimicrobial, Polymer, MALDI-TOF MS
National Category
Polymer Chemistry
URN: urn:nbn:se:kth:diva-26717DOI: 10.1016/j.polymdegradstab.2010.06.024ISI: 000281369500003ScopusID: 2-s2.0-77955511183OAI: diva2:372658
QC 20101126Available from: 2010-11-26 Created: 2010-11-26 Last updated: 2011-05-11Bibliographically approved
In thesis
1. Antimicrobial Polymer Composites for Medical Applications
Open this publication in new window or tab >>Antimicrobial Polymer Composites for Medical Applications
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The current study and discuss the long-term properties of biomedical polymers in vitro and invivo and presents means to design and manufacture antimicrobial composites. Antimicrobialcomposites with reduced tendency for biofilm formation should lead to lower risk for medicaldevice associated infection.The first part analyse in vivo degradation of invasive silicone rubber tracheostomy tubes andpresents degradation mechanism, degradation products and the estimated lifetime of thematerials.. It was found that silicone tubes undergo hydrolysis during the long-term exposurein vivo, which in turn results in decreased stability of the polymer due to surface alterationsand the formation of low molecular weight compounds.The second part of the study presents the manufacturing of composites with single, binary andternary ion-exchanged zeolites as an antimicrobial agent. The ion distribution and release ofthe zeolites and the antimicrobial efficiency of the different systems showed that single silverion-exchanged zeolite was superior to the other samples. Antimicrobial composites wereprepared by mixing the above-mentioned zeolites and pure zeolite (without any ion) withdifferent fractions into polyether (TPU), polyether (PEU) polyurethane and silicone rubber.The antimicrobial efficiency of binary and ternary ion-exchanged samples was similar whichis thought to be due to the ion distribution in the crystal structure.The changes in the mechanical and surface properties of the composites due to the zeolitecontent demonstrated that the increasing zeolite content reduced the mechanical propertieswhile the surface properties did not change significantly. The antimicrobial tests showed thatthe silver-containing composite was the most efficient among all the other samples. Thebinary and ternary ion-exchanged composites expressed similar antimicrobial efficiency as itwas seen previously for the different zeolite systems. Biocompatibility was studied byexposure to artificial body fluids to simulate the degradation of the composites in the humanbody. Significant changes were observed in the morphology, the surface properties and the chemical structure.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. 79 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2011:19
medical polymers, antimicrobial, body fluids, degradation
National Category
Polymer Chemistry
urn:nbn:se:kth:diva-33393 (URN)978-91-7415-899-1 (ISBN)
Public defence
2011-05-13, F3, Lindstedtsvägen 23 KTH, Stockholm, 13:00 (English)
QC 20110511Available from: 2011-05-11 Created: 2011-05-05 Last updated: 2011-05-11Bibliographically approved

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