Influence of sterilisation methods on collagen-based devices stability and properties

Abstract

Sterilisation is essential for any implantable medical device in order to prevent infection in patients. The selection of the most appropriate sterilisation method depends on the nature and the physical state of the material to be sterilised; the influence of the sterilisation method on the properties of the device; and the type of the potential contaminant. In this context, herein we review the influence of ethylene oxide, γ-irradiation, e-beam irradiation, gas plasma, peracetic acid and ethanol on structural, biomechanical, biochemical and biological properties of collagen-based devices. Data to-date demonstrate that chemical approaches are associated with cytotoxicity, whilst physical methods are associated with degradation, subject to the device physical characteristics. Thus, the sterilisation method of choice is device dependent.

Keywords::

• collagen biomaterials
• degradation rate
• mechanical properties
• sterilization
• structural stability
• tissue grafts

Financial & competing interests disclosure

This article was supported by the European Union Seventh Framework Programme (FP7/2007-2013), under agreement number 263289 (Green Nano Mesh); European Union Seventh Framework Programme (FP7/2007-2013), under grant agreement number 251385 (Tendon Regeneration); Science Foundation Ireland, Research Frontiers Programme, under the grant agreement number 09/RFP/ENM2483; Health Research Board, Health Research Awards Programme, under the grant agreement number HRA_POR/2011/84 and Tissue Regenix Group Plc. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• All sterilization methods affect differently structural, mechanical and biological properties of collagen-based devices.

• Ethylene oxide is associated with reduction in shrinkage temperature, reduction in mechanical properties and increase in cytotoxicity, if an effective aeration step is not completed.

• γ-Irradiation induces cleavage of collagen chains, decreases mechanical properties and increases enzymatic degradation rate.

• E-beam irradiation causes structural instability, reduction in mechanical properties and increases hydrolytic degradation.

• Preliminary results indicate that gas plasma is efficient for thin and moisture-free devices.

• The use of radioprotectants may improve stability of extracellular matrix-based devices during irradiation; however, more detailed studies are required.

• Peracetic acid and ethanol do not denature extracellular matrix-based devices; however, they affect porosity and biomechanical properties.

• Sterilization method of choice is ‘device dependent’ and rigorous clinical target-specific in vitro and in vivo analysis should be carried out prior to decision.