The Impact of γ-Irradiation and EtO Degassing on Tissue Remodeling of Collagen-based Hybrid Tubular Templates

Abstract

Clinical implementation of novel products for tissue engineering and regenerative medicine requires a validated sterilization method. In this study, we investigated the effect of γ-irradiation and EtO degassing on material characteristics in vitro and the effect on template remodeling of hybrid tubular constructs in a large animal model. Hybrid tubular templates were prepared from type I collagen and Vicryl polymers and sterilized by 25 kGray of γ-irradiation or EtO degassing. The in vitro characteristics were extensively studied, including tensile strength analysis and degradation studies. For in vivo evaluation, constructs were subcutaneously implanted in goats for 1 month to form vascularized neo-tissue. Macroscopic and microscopic appearances of the γ- and EtO-sterilized constructs slightly differed due to additional processing required for the COL-Vicryl-EtO constructs. Regardless of the sterilization method, incubation in urine resulted in fast degradation of the Vicryl polymer and decreased strength (<7 days). Incubation in SBF was less invasive, and strength was maintained for at least 14 days. The difference between the two sterilization methods was otherwise limited. In contrast, subcutaneous implantation showed that the effect of sterilization was considerable. A well-vascularized tube was formed in both cases, but the γ-irradiated construct showed an organized architecture of vasculature and was mechanically more comparable to the native ureter. Moreover, the γ-irradiated construct showed advanced tissue remodeling as shown by enhanced ECM production. This study shows that the effect of sterilization on tissue remodeling cannot be predicted by in vitro analyses alone. Thus, validated sterilization methods should be incorporated early in the development of tissue engineered products, and this requires both in vitro and in vivo analyses.

Effect of High Hydrostatic Pressure on Human Trabecular Bone Regarding Cell Death and Matrix Integrity

“…The temperatures of 1,000°C and more used in industry for thermal processing of allografts lead to an irreversible denaturation of proteins due to polypeptide chain break up ( Lambri et al, 2016 ; Botiss-dental, 2021 ). Gamma irradiation causes either polypeptide chain scissions due to direct ionization or changes in crosslinking through the formation of highly reactive hydroxyl radicals, which both lead to a loss of protein integrity ( Sloff et al, 2018 ; Silva Aquino, 2012 ). In both cases, the primary structure of proteins is destroyed.…”

The effect of source animal age, decellularization protocol, and sterilization method on bovine acellular dermal matrix as a scaffold for wound healing and skin regeneration

“…Moreover, the scission of pre‐existed intermolecular crosslinks increases the effective size of ECM domains that can unfold and thus elevate the denaturation enthalpy. On the contrary, degradation of collagen molecules reduces denaturation temperature and enthalpy 72 . The summation of these events and their magnitude determines the ultimate thermal stability of the irradiated ECM.…”

“…On the contrary, degradation of collagen molecules reduces denaturation temperature and enthalpy. 72 The summation of these events and their magnitude determines the ultimate thermal stability of the irradiated ECM. However, sterilization with EO was shown to have no apparent effect on the thermal stability of collagen-based constructs compared to untreated samples.…”

Natural Polymers and Their Processing: Bottlenecks to Overcome Their Limitations in Medical Applications

“…Hydrogen peroxide gas plasma is not recommended for porous biomaterials, H 2 O 2 may adsorb into the surface [126]. Ethylene oxide should be used when it is possible to remove all toxic residues after sterilization and it does not significantly affect the biopolymers properties [127]. The study from Gelinsky et al [128] indicated that mechanical properties of biopolymers were less compromised by scCO 2 compared to classical sterilization methods.…”