Preliminary Study on the Simulation of a Radiation Damage Analysis of Biodegradable Polymers

Abstract

In this study, biodegradable poly(L-lactide-co-ε-caprolactone) (PLCL) and poly(L-co-d,l lactide) (PLDLA) were evaluated using Geant4 (G4EmStandardPhysics_option4) for damage simulation, in order to predict the safety of these biodegradable polymers against gamma ray sterilization. In the PLCL damage model, both chain scission and crosslinking reactions appear to occur at a radiation dose in the range 0–200 kGy, but the chain cleavage reaction is expected to be relatively dominant at high irradiation doses above 500 kGy. On the other hand, the PLDLA damage model predicted that the chain cleavage reaction would prevail at the total irradiation dose (25–500 kGy). To verify the simulation results, the physicochemical changes in the irradiated PLCL and PLDLA films were characterized by GPC (gel permeation chromatography), ATR-FTIR (attenuated total reflection Fourier transform infrared), and DSC (difference scanning calorimetry) analyses. The Geant4 simulation curve for the radiation-induced damage to the molecular weight was consistent with the experimentally obtained results. These results imply that the pre-simulation study can be useful for predicting the optimal irradiation dose and ensuring material safety, particularly for implanted biodegradable materials in radiation processing.

Evaluation of the sterilization effect on biphasic scaffold based on bioactive glass and polymer honeycomb membrane

“…Furthermore, FTIR spectra were recorded pre-and postirradiation, and no significant difference could be evidenced (data not shown). This agrees with a study by Shim et al 16 who reported that, at gamma-rays doses ranging from 25 to 500 kGy, no significant difference in the polymer chain, and notably the polymer functional groups, before and after irradiation could be seen. In addition, Pérez Davila et al reported a 99.8% similarity in FTIR spectra recorded pre-and postirradiation (25 kGy) of PLA 3D scaffolds.…”

“…However, the Mw of the polymer decreases from ≈350.000 to ≈175.000 g/mol after irradiation, independently of the BG composition. A similar decrease in Mw of polymer was reported by Nugroho et al 42 and Shim et al 16 and can be related to random chain scission. Furthermore, FTIR spectra were recorded pre-and postirradiation, and no significant difference could be evidenced (data not shown).…”

“…However, it is generally accepted that high dose of gamma radiation leads to a decrease in the average molecular weight (Mw) of the PLDLA through chain scission. 16 Studies have shown that such effect typically occurs at dose greater than 25 kGy. However, already at 25 kGy, simulations have shown that the Mw of PLDLA 96/4 was decreased by almost 50%.…”

“…However, already at 25 kGy, simulations have shown that the Mw of PLDLA 96/4 was decreased by almost 50%. 16 In the case of our biphasic material, it is therefore crucial to assess the change in average Mw as well as to ensure that the interface between the BG and the membrane remains stable postirradiation.…”

“…[5], is made of PLDLA. However, it is generally accepted that high dose of gamma radiation leads to a decrease in the average molecular weight (Mw) of the PLDLA through chain scission 16 . Studies have shown that such effect typically occurs at dose greater than 25 kGy.…”