Beekman, J1, Wang, Y 2, Suarez, F3, Fathi, A4, van Zuijlen, P5, Maitz, P6, Li, Z7

1 Burns Research, ANZAC Research Institute, Concord Repatriation General Hospital, Gate 3, Hospital Rd, Concord NSW 2139, joanneke.beekman@sydney.edu.au
2 Burns Research, ANZAC Research Institute, Concord Repatriation General Hospital, Gate 3, Hospital Rd, Concord NSW 2139, yiweiwang@anzac.edu.au
3 Burns Research, ANZAC Research Institute, Concord Repatriation General Hospital, Gate 3, Hospital Rd, Concord NSW 2139,
20160914@my.nd.edu.au
4 Bioengineering and Biophysics, Chemical Engineering Building – J01, University of Sydney, Cnr Shepherd Street and Lander Street, Darlington, NSW, 2006, ali.fathi@sydney.edu.au
5 Burns Unit, Red Cross Hospital, Vondellaan 13, 1942 LE Beverwijk, Netherlands, pvanzuijlen@rkz.nl
6 Burns Unit & ANZAC Research Institute, Concord Repatriation General Hospital, Gate 3, Hospital Rd, Concord NSW 2139, peter.maitz@sydney.edu.au
7 Burns Unit & ANZAC Research Institute, Concord Repatriation General Hospital, Gate 3, Hospital Rd, Concord NSW 2139, zhe.li@sswahs.nsw.gov.au

Abstract
Introduction
MatriDerm, a non-cross-linked dermal template, is commonly used in full thickness wounds to accelerate dermal regeneration and improve scar tissue quality. Cross-linking the fibres together could potentially enhance the stability, strength and performance of the dermal scaffold.

Aim
The aim is to investigate the effects of cross-linking on MatriDerm degradation and wound contraction using established cell culture and mouse models.

Method
MatriDerm was cross-linked with glutaraldehyde vapour (2.5%) and characterized in comparison with non-cross-linked MatriDerm. Scaffold properties, stability and elasticity were assessed through scanning electron microscopy, measurement of protein loss with an assay kit, and tensile testing, respectively. The scaffold degradation and its impact on wound contraction was studied in an animal model. Cell-scaffold interaction and cell migration was examined using human dermal fibroblasts.

Results
After cross linking, MatriDerm displayed a significant but slightly reduced pore size, a significant delay in total protein loss and a 3 fold increase of elasticity. In the mouse model, non-cross-linked MatriDerm was almost completely biodegraded at day 14 but cross-linked MatriDerm remained intact with cell infiltration. Interestingly, in-vivo study showed no significant difference in wound contraction between cross-linked and non-cross-linked MatriDerm. Initial data shows a similar host response in angiogenesis and elastin production in both scaffolds. Analyses in cell culture models are still being performed.

Conclusion
Cross-linked MatriDerm showed a significant increase in stability and elasticity compared to non-cross-linked MatriDerm. Although wound contraction was found comparable, cross-linked MatriDerm in the mouse models showed a reduced biodegradation rate and a similar host response.

Key Words
MatriDerm, cross-linking, wound contraction, scaffold degradation