Quality Monitoring of Porous Zein Scaffolds: A Novel Biomaterial

Our previous studies have shown that zein has good biocompatibility and good mechanical properties. The first product from a porous scaffold of zein, a resorbable bone substitute, has passed the biological evaluation of medical devices (ISO 10993) by the China Food and Drug Administration. However, Class III medical devices need quality monitoring before being placed on the market, and such monitoring includes quality control of raw materials, choice of sterilization method, and evaluation of biocompatibility. In this paper, we investigated four sources of zein through amino acid analysis (AAA) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in order to monitor the composition and purity, and control the quality of raw materials. We studied the effect of three kinds of sterilization method on a porous zein scaffold by SDS-PAGE. We also compared the changes in SDS-PAGE patterns when irradiated with different doses of gamma radiation. We found that polymerization or breakage did not occur on peptide chains of zein during gamma-ray (γ-ray) sterilization in the range of 20–30 kGy, which suggested that γ-ray sterilization is suitable for porous zein scaffolds. Regarding cell compatibility, we found a difference between using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and a cell-counting kit-8 (CCK-8) assay to assess cell proliferation on zein film, and concluded that the CCK-8 assay is more suitable, due to its low background optical density.