Cell-based detection of microbial biomaterial contaminations

Issue title: Special issue: Advanced Functional Polymers in Medicine (AFPM): Liège, Belgium, May 2014; Guest-Editors: Christine Jérôme and Andreas Lendlein

Article type: Research Article

Authors: Roch, Toralf^{a; b; *} | Ma, Nan^{a; b; c} | Kratz, Karl^{a; b} | Lendlein, Andreas^{a; b; c; d}

Affiliations: [a] Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Teltow, Germany | [b] Helmholtz Virtual Institute – Multifunctional Biomaterials for Medicine, Teltow and Berlin, Germany | [c] Department of Biology, Institute of Chemistry and Biochemistry, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany | [d] Institute of Chemistry, University of Potsdam, Potsdam, Germany

Correspondence: [*] Corresponding author: Toralf Roch, Institute of Biomaterial Science, Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany. Tel.: +49 3328 352459; Fax: +49 3328 352452; toralf.roch@hzg.de

Abstract: A major challenge in biomaterial synthesis and functionalization is the prevention of microbial contaminations such as endotoxins (lipopolysaccharides (LPS)). In addition to LPS, which are exclusively expressed by Gram negative bacteria, also other microbial products derived from fungi or Gram positive bacteria can be found as contaminations in research laboratories. Typically, the Limulus amebocyte lysate (LAL)-test is used to determine the endotoxin levels of medical devices. However, this test fails to detect material-bound LPS and other microbial contaminations and, as demonstrated in this study, detects LPS from various bacterial species with different sensitivities. In this work, a cell-based assay using genetically engineered RAW macrophages, which detect not only soluble but also material-bound microbial contaminations is introduced. The sensitivity of this cell-line towards different LPS species and different heat-inactivated microbes was investigated. As proof of principle a soft hydrophobic poly(n-butyl acrylate) network (cPnBA), which may due to adhesive properties strongly bind microbes, was deliberately contaminated with heat-inactivated bacteria. While the LAL-test failed to detect the microbial contamination, the cell-based assay clearly detected material-bound microbial contaminations. Our data demonstrate that a cell-based detection system should routinely be used as supplement to the LAL-test to determine microbial contaminations of biomaterials.

Keywords: Biomaterials, polymers, endotoxins, microbial contaminations, immuno-compatibility

DOI: 10.3233/CH-151939

Journal: Clinical Hemorheology and Microcirculation, vol. 60, no. 1, pp. 51-63, 2015