2012|13 Annual Report Fraunhofer IGB

85 Dr. Michaela Müller Phone +49 711 970-4140 michaela.mueller@igb.fraunhofer.de Dr. Iris Trick Phone +49 711 970-4217 iris.trick@igb.fraunhofer.de References [1] Weber, C.; Burger-Kentischer, A.; Müller, M.; Trick, I.; Hirth, T. (2011) Bioﬁlmvermeidung durch natürliche Wirkstoffe – gezielte und langfristige Freisetzung durch ein PEG-basiertes Depotsys- tem, Biomaterialien 12: 2 Control of release and antimicrobial action The release characteristics were studied at room temperature and in a phosphate-buffered saline solution, which was regu- larly changed. Fig. 3 shows the quantity of lysozyme released over 100 days, depending on the network density. The largest amount is released within the ﬁrst days but output was still detected after even 100 days. At this point, 50 percent of the total lysozyme applied had been released. The release itself can be adjusted via the prepared network density. The systems described were investigated for their antimicrobi- al, bacteriostatic action with E. coli, P. aeruginosa and P. pseu- doalcaligenes. Their effect was examined in planktonic and bioﬁlm cells. Fig. 4 shows the statistically signiﬁcant reduction in the metabolic activity of the microorganisms studied, in comparison to the reference bioﬁlm, by the prepared systems. A statistically signiﬁcant reduction in the planktonic cell count was also achieved for hydrogels with lysozyme and LL-37. Outlook We were able to show that natural antimicrobial agents can be embedded in deposit layers, while retaining their function and their release can be controlled through the design of this layer. The prepared systems had an antimicrobial action in the microorganisms studied. Natural antimicrobial materials usual- ly have a narrow spectrum of action, so technical applications may require combinations of agents for the prevention of the undesirable microorganisms present. The deposit layer must thereby be matched to the agent to be released in each case. 1 Water ﬁlter clogged with bioﬁlm. 2 Coating of a hydrogel containing an anti- microbial agent to the surface of a material. 3 Release characteristics of an active agent from a hydrogel. 4 Reduction of the bioﬁlm by hydrogel loaded with active agent. 3 4 Contacts 6000 5000 4000 2000 1000 0 0 50 100 Concentrationofreleasedprotein [μg/500μlhydrogel] Release period (d) 10% PEG-DA, lysozyme 25% PEG-DA, lysozyme 200 150 100 50 0 Relativemetabolicactivityofbioﬁlm[%] Lysozyme LL-37Bioﬁlm DNAseHydrogel E.coli MG1655 P.pseudoalcaligenes DSM 7418 P.aeruginosa PAO1

2012|13 Annual Report Fraunhofer IGB

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