Leila Cuttle1, JD Iljas2, Jacqui McGovern3, Benjawan Boonkaew4, Margit Kempf5, Roy Kimble6, Tony Parker7

1 Centre for Children’s Burns and Trauma Research, Centre for Children’s Health Research, Queensland University of Technology, Institute of Health and Biomedical Innovation at Centre for Children’s Health Research, South Brisbane, QLD 4101, leila.cuttle@qut.edu.au
2 Tissue Repair and Regeneration Program, Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, QLD; University Utrecht, Utrecht, The Netherlands, jd.iljas@gmail.com
3 Tissue Repair and Regeneration Program, Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, QLD Jacqui.mcgovern@qut.edu.au
4 Centre for Children’s Burns and Trauma Research, Centre for Children’s Health Research, University of Queensland, South Brisbane, QLD 4101 ben_ben981@hotmail.com
5 Centre for Children’s Burns and Trauma Research, Centre for Children’s Health Research, University of Queensland, South Brisbane, QLD 4101 kempfm@uq.edu.au
6 Pegg-Ledischtke Children’s Burns Centre, Lady Cilento Children’s Hospital, South Brisbane, QLD 4101 royk@uq.edu.au
7 Tissue Repair and Regeneration Program, Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane QLD, a.parker@qut.edu.au

Burns are treated with silver dressings because of their antimicrobial efficacy, however they have also been reported to be cytotoxic to cells and newly forming skin. We have studied the effects of common silver dressings (Acticoat, Mepilex Ag) on in vitro 2D cell culture, ex-vivo 3D reconstructed skin burns and in vivo porcine burns. In vitro exposure of HaCaT, primary keratinocytes and primary fibroblasts to silver dressings showed decreased cell viability in MTT assays at 24, 48 and 72h. Surprisingly, the most cytotoxic agent (Acticoat) was found to cause an increase in number/viability of fibroblasts and HaCaTs but not keratinocytes at 72h. An ex vivo skin reconstruct burn model was created from surgical skin discards to study silver particle localisation in the skin. Autometallography staining and Electron Microscopy of Acticoat treated burned skin showed silver complexes had penetrated into the dermis, but were only sitting on the surface of unburned skin. This was confirmed by Laser-Ablation inductively coupled mass spectrometry. Acticoat did not delay regrowth of neo-epidermis in the ex vivo burn model. When silver dressings were applied to a porcine contact burn wound model, they prevented colonisation/infection but did not delay wound healing or increase scarring. In conclusion: 1) HaCaT cells are not representative of primary keratinocytes; 2) we have created a new ex vivo 3D reconstructed skin burn model for testing treatments; 3) although silver dressings are cytotoxic to skin cells in vitro, they do not appear to delay burn wound healing in ex vivo or for in vivo burn wounds.

Key Words
Silver dressing, cytotoxicity, antimicrobial, ex vivo