Substantiation of 25 kGy radiation sterilization dose for banked air dried amniotic membrane and evaluation of personnel skill in influencing finished product bioburden

Abstract

Preparation of amniotic membrane (AM) by air drying method followed by radiation sterilization is simple and valuable approach; sterility and quality of the final AM product are depending on the quality management system at the tissue bank. Validation and substantiation of radiation sterilization dose (RSD) for tissue allografts is an essential step for the development and validation of the standard operating procedures (SOP). Application of SOP is perfectly relying on trained staff. Skills differences among personnel involved in AM preparation could have an effect on microbiological quality of the finished product and subsequently on the RSD required. AM were processed by four different couples of the tissue bank technicians. The AM grafts were randomly selected and subjected to bioburden test to validate and substantiate the 25 kGy RSD. Bioburden test for AM grafts were also useful to evaluate the skill of the tissue bank technicians and thus, to validate the current SOP for air dried AM. Moreover, the effect of placental source on bioburden counts on AM grafts was assessed. Substantiation of the 25 kGy RSD at a sterility assurance level of 10−1, and sample item portion = 1, was carried out using Method VDmax25 of the International Organization for Standardization, document no. 11137-2 (ISO in Sterilization of healthcare products—radiation—part 2: establishing the sterilization dose, Method VDmax—substantiation of 25 kGy or 15 kGy as the sterilization dose, International Standard Organization, 2006). The results showed that there were no significant differences in the bioburdens of the four batches (α = 1 %), this means no significant differences in the skill of the four couples of the tissue bank technicians in terms of their ability to process AM according to the air dried AM SOP. The 25 kGy RSD was validated and substantiated as a valid sterilization dose for the AM prepared with the current established SOP at the Biotechnology Research Center experimental tissue bank. The donor’s type of delivery, normal or caesarean, showed no significant effect on the levels of microbial counts on the tested AMs (α = 1 %).

A review of decellurization methods caused by an urgent need for quality control of cell‐free extracellular matrix' scaffolds and their role in regenerative medicine

“…For reasons of biological security, decellularized tissues and organs need a final sterilization [143][144][145][146][147] prior to clinical application. The use of sterilization procedures, such as the exposure of the material to ethylene oxide, gamma, or electron beam radiation, may significantly influence the structure of the ECM and may negatively affect mechanical properties of the biomaterial.…”

Effects of Chemical and Radiation Sterilisation on the Biological and Biomechanical Properties of Decellularised Porcine Peripheral Nerves

“…PAA solution, gamma radiation, E Beam and ethylene oxide were initially selected as candidate sterilisation methods due to their proven efficacy in terms of bioburden reduction, demonstrated either through the existence of a relevant standard (e.g., ISO 11137 for ionising radiations), or via prior data indicating that a sterility assurance level equivalent to that stipulated in BS EN 556-1 can be achieved through the application of a given method (e.g., ISO 14160 and ISO 11135). In addition, there is an established evidence base for the use of PAA (e.g., decellularised human dermis), gamma radiation (e.g., allogeneic amniotic membrane, decellularised human dermis, decellularised porcine superflexor tendon), and E Beam (e.g., decellularised porcine superflexor tendon, human flexor digitorum superficialis tendon) indicating possible compatibility with soft tissue grafts ( Singh et al, 2004 , 2016 ; Wei et al, 2013 ; Marsit et al, 2014 ; Hogg et al, 2015 ; Edwards et al, 2017 ; Gabriel and Maxwell, 2018 ). Ethylene oxide was considered for inclusion as a candidate sterilisation method due to its efficacy (in terms of bioburden reduction) and previous history of use in tissue banking, particularly with bone allografts ( Prolo et al, 2013 ).…”

Obtaining of Xenogenic Vascular Scaffolds

“…The irradiation energy was up to 10 MEV, and the average current was 1 mA [4]. A dose of 25 kGy was chosen as the minimum required to ensure the sterility of medical materials [5].…”