Bertoldi Serena, Farè Silvia, Haugen Håvard Jostein, Tanzi Maria Cristina
Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133, Milan, Italy,
J Mater Sci Mater Med. 2015 May;26(5):182. doi: 10.1007/s10856-015-5509-0. Epub 2015 Apr 17.
Porous polyurethane (PU) structures raise increasing interest as scaffolds in tissue engineering applications. Understanding the effects of sterilization on their properties is mandatory to assess their potential use in the clinical practice. The aim of this work is the evaluation of the effects of two innovative sterilization techniques (i.e. plasma, Sterrad(®) system, and ozone) on the morphological, chemico-physical and mechanical properties of a PU foam synthesized by gas foaming, using water as expanding agent. In addition, possible toxic effects of the sterilization were evaluated by in vitro cytotoxicity tests. Plasma sterilization did not affect the morphological and mechanical properties of the PU foam, but caused at some extent degradative phenomena, as detected by infrared spectroscopy. Ozone sterilization had a major effect on foam morphology, causing the formation of new small pores, and stronger degradation and oxidation on the structure of the material. These modifications affected the mechanical properties of the sterilized PU foam too. Even though, no cytotoxic effects were observed after both plasma and ozone sterilization, as confirmed by the good values of cell viability assessed by Alamar Blue assay. The results here obtained can help in understanding the effects of sterilization procedures on porous polymeric scaffolds, and how the scaffold morphology, in particular porosity, can influence the effects of sterilization, and viceversa.
多孔聚氨酯（PU）结构作为组织工程应用中的支架越来越受到关注。了解灭菌对其性能的影响对于评估其在临床实践中的潜在用途至关重要。这项工作的目的是评估两种创新灭菌技术（即等离子体、Sterrad®系统和臭氧）对以水为发泡剂通过气体发泡合成的PU泡沫的形态、化学物理和机械性能的影响。此外，通过体外细胞毒性试验评估了灭菌可能产生的毒性作用。等离子体灭菌不影响PU泡沫的形态和机械性能，但通过红外光谱检测发现，在一定程度上会引起降解现象。臭氧灭菌对泡沫形态有较大影响，导致形成新的小孔，并对材料结构产生更强的降解和氧化作用。这些改性也影响了灭菌后PU泡沫的机械性能。尽管如此，通过Alamar Blue法评估的良好细胞活力值证实，等离子体和臭氧灭菌后均未观察到细胞毒性作用。这里获得的结果有助于理解灭菌程序对多孔聚合物支架的影响，以及支架形态，特别是孔隙率，如何影响灭菌效果，反之亦然。
