Gamma irradiation of electrospun poly(ε‐caprolactone) fibers affects material properties but not cell response

Abstract

Fabrication of electrospun fibrous scaffolds as future medical devices is being widely researched, with particular emphasis given to their material properties and effect on cell response and differentiation. However, the vast majority of these scaffolds are sterilized via nonmedically approved methods, including submersion in ethanol and exposure to UV light. Although these techniques are adequate for laboratory-based research, they are not sufficient for human implantation. In this case, regulatory approved, medical grade sterilization is required. In this study, we report the effects of gamma irradiation, a regulatory approved technique, on electrospun poly(ecaprolactone) fibers. Fabricated fibers were separately subjected to different dosages of irradiation ranging from 0 to 45 kGy and then assessed for their physicochemical properties. Gamma irradiation affected fiber properties irrespective of dosage. A dose-dependent decrease in polymer molecular weight was observed and an increase in melting point and crystallinity reported. Similarly, irradiation had a significant effect on mechanical properties with greatest decrease in tensile strength (68%) for fibers exposed to 40 kGy. The method of sterilization had no effect on cell response. Seeded tenocytes attached to all fibers and elongated parallel to the underlying fiber direction. The results demonstrate the importance of incorporating medical grade sterilization procedures early in the research projects time line to assist translation from bench to clinic.

Dose-Dependent Effects of Gamma Irradiation on the Materials Properties and Cell Proliferation of Electrospun Polycaprolactone Tissue Engineering Scaffolds

“…Thus the higher irradiation dose resulted in inferior tensile properties. Maximum elongation achieved by the gamma irradiated membranes, did not show significant differences compared with the unirradiated PCL membranes which is in agreement with the previous studies [20].…”

“…The highest percentage of crystallinity among the studied samples was 69.62 which were obtained for sample irradiated with 35 kGy. The results show that exposure to lower gamma dose results into the enhancement of crystallinity, which leads to the ordering in the polymer chains [20].…”

“…XRD results reflected that the amorphous character of the polymer decreases and crystallinity increases with increase in irradiation dose. This might be due to scissioning of the polymer chains and the possible spatial rearrangement that occurred in the polymer [20]. Highly crystalline polymers show superior tensile properties than amorphous one.…”

Effect of Sterilization Methods on Electrospun Poly(lactic acid) (PLA) Fiber Alignment for Biomedical Applications

“…Instead, on fibre aligned substrates, cells were consistently aligned along the longitudinal axis of the polymer fibres, with an elongated morphology, with no detectable differences being observed for both substrate irradiation methods (figure 8b and d). A similar behaviour has been reported for PCL electrospun fibres treated by -radiation for doses up to 45 kGy, in which despite affecting polymer thermal and mechanical properties, did not impaired the cellular behaviour 41 . Figure 8 -Scanning electron micrographs of MG63 osteoblastic-like cells seeded on electrospun PLA membranes after sterilization treatments: (a) random fibre membranes sterilized by UV radiation, (b) aligned fibre membranes sterilized by UV radiation (c) random fibre membranes sterilized by -rays radiation (d) aligned fibre membranes sterilized by -rays radiation.…”

Travelling along the Clinical Roadmap: Developing Electrospun Scaffolds for Tendon Repair

“…It is important that the sterilisation technique is determined early in the project's timeline, as years of research could be wasted if the properties of the device change drastically or the material is unable to achieve sterility. A recent study conducted on our electrospun fibres proved that gamma irradiation had a significant impact on their tensile properties [14]. Irrespective of gamma dose, both Young's modulus and tensile strength were more than halved compared to the virgin scaffold.…”