Cytotoxicity of three-dimensional paper-based models from a three-dimensional paper-based printer

Abstract

Objective: Our study aimed to determine the possibility of using models created with a low-cost, paper based 3D printer in an operating room. Therefore influence of different methods of sterilization on models was tested and cytotoxicity of generated models was determined. 
Material and methods: 30 cuboids divided into three groups were used for verification of shape stability after sterilization. Each group was sterilized either with: Ethylene oxide in temperature 55˚C, Hydrogen peroxide gas plasma in temperature 60˚C or Gamma irradiation at 21˚C, 25kGy. Each cuboid was measured using calliper three times before and three times after sterilization. Results were analysed statistically in Statgraphics Plus. Statistical significance was determined as p< 0.05. Sixty cylinders divided into six groups were used for cytotoxicity tests. Three of those groups were covered before sterilization with 2-octyl-cyanoacrylate. Each group was sterilized with one of the previously described methods. Cytotoxicity was tested by Nanostructural and Molecular Biophysics Laboratory in Technopark Lodz using normal adult human dermal fibroblasts. Survival of cells was tested using spectrophotometry with XTT and was defined as ratio of absorbency of tested probe to absorbency of control probe. Calcein/Ethidium dyeing test was performed according to LIVE/DEAD Viability/Cytotoxicity Kit protocol. Observation was done under Olympus GX71 fluorescence microscope. Results: There was no statistically significant difference for established statistical significance p=0.05 in cuboids dimensions before and after sterilization regardless of sterilization method. In XTT analysis all samples showed higher cytotoxicity against normal, human, adult dermal fibroblast culture when compared to positive control. ANOVA statistical analysis confirmed that 2-octyl cyanoacrylate coating of paper model improved biological behaviour of the material. It decreased cytotoxicity of the model independently of sterilization method. In calcein/ethidium dyeing test due to the high fluorescence of the background caused by cylinders of analysed substance it was impossible to perform the exact analysis of the number of marked cells. 
Conclusions: Acquired results allow to conclude that Mcor Technology Matrix 300 3D paper-based models can be used in operating room only if covered with cyanoacrylate tissue adhesive. 
Nemesis relevance: We found no statistically significant difference in cuboids dimensions before and after sterilization regardless of sterilization method. Three-dimensional paper-based models present with high cytotoxicity without coating.