Evaluation of Sterilisation Techniques for Regenerative Medicine Scaffolds Fabricated with Polyurethane Nonbiodegradable and Bioabsorbable Nanocomposite Materials.

Michelle Griffin,Alexander M Seifalian,Peter E M Butler,Deepak M Kalaskar,Naghmeh Naderi,Catherine A Thornton,Ash Mosahebi,Remzi Becer,Iain S Whitaker,Edward Malins

doi:10.1155/2018/6565783

Abstract

An effective sterilisation technique that maintains structure integrity, mechanical properties, and biocompatibility is essential for the translation of new biomaterials to the clinical setting. We aimed to establish an effective sterilisation technique for a biodegradable (POSS-PCL) and nonbiodegradable (POSS-PCU) nanocomposite scaffold that maintains stem cell biocompatibility. Scaffolds were sterilised using 70% ethanol, ultraviolet radiation, bleach, antibiotic/antimycotic, ethylene oxide, gamma irradiation, argon plasma, or autoclaving. Samples were immersed in tryptone soya broth and thioglycollate medium and inspected for signs of microbial growth. Scaffold surface and mechanical and molecular weight properties were investigated. AlamarBlue viability assay of adipose derived stem cells (ADSC) seeded on scaffolds was performed to investigate metabolic activity. Confocal imaging of rhodamine phalloidin and DAPI stained ADSCs was performed to evaluate morphology. Ethylene oxide, gamma irradiation, argon plasma, autoclaving, 70% ethanol, and bleach were effective in sterilising the scaffolds. Autoclaving, gamma irradiation, and ethylene oxide led to a significant change in the molecular weight distribution of POSS-PCL and gamma irradiation and ethylene oxide to that of POSS-PCU (p<0.05). UV, ethanol, gamma irradiation, and ethylene oxide caused significant changes in the mechanical properties of POSS-PCL (p<0.05). Argon was associated with significantly higher surface wettability and ADSC metabolic activity (p<0.05). In this study, argon plasma was an effective sterilisation technique for both nonbiodegradable and biodegradable nanocomposite scaffolds. Argon plasma should be further investigated as a potential sterilisation technique for medical devices.

Highlights

Synthetic biomaterials are being used to replace the extracellular matrix to restore damaged and failing tissues and organs [1]
The first authors of this paper have demonstrated that bleach may be useful for sterilising polyhedral oligomeric silsesquioxane (POSS)-PCL scaffolds compared to ethanol and autoclaving sterilisation [8]
The POSS-PCU samples were unaffected by the autoclaving process, the POSS-PCL samples were destroyed; it was not possible to examine the autoclaved POSS-PCL samples further

Summary

Introduction

Synthetic biomaterials are being used to replace the extracellular matrix to restore damaged and failing tissues and organs [1]. Polymeric scaffolds have gained significant popularity due to their ease of fabrication and versatility [1]. Polymeric scaffolds for tissue engineering are either manufactured aseptically or sterilised after processing. The challenge remains to determine an efficient and nondestructive sterilisation procedure for polymer scaffolds that preserves their structure and surface properties [3]. Sterilisation techniques may influence a material’s structural, chemical, and biological properties; it is important to ensure the modality implemented does not affect biocompatibility [3]. The success of an implant for sterilisation is dependent on the implant remaining sterile, and on achieving sterility without adversely affecting the material’s properties. Different sterilisation agents have shown that they can attack polymers causing hydrolysis, melting, or depolymerisation [5, 6]

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