Biological Properties Of Geopolymer Carriers In Novel Composite Resins

To produce a new biocompatible antimicrobial resin with geopolymer as the carrier of nano-zinc oxide without compromising the mechanical properties. We mixed metakaolin powder and 1% (wt/wt) nano zinc oxide with phosphoric acid and sodium silicate-sodium hydroxide solutions respectively, further solidified at 60°C for 24h to obtain acid and alkali-activated geological polymers. After a 2-hour-sterilization in 75% ethanol, the samples were soaked in medium at 0.2 g/mL as standard, incubated at 37°C and 5% CO2 in a humidified environment for 24 h and adjusted the pH to 7.4. We seeded MC3T3-E1 into 96-well plates and incubated with the extract for 24 h, using CCK-8 to evaluate the biocompatibility based on survival rate. We grinded geopolymer into nano-scale and silanized with γ-MPS at a ratio of 50:1 (wt/wt), mixing with resin matrix. After ultraviolet-curing, we evaluated the biocompatibility and messured the antibacterial (Streptococcus mutans) activity by the bacteriostatic zone method. Z350 resin was used as the control group to compare the flexural strength and compressive strength. Compared with the cell survival rate of acid-activated geopolymers (65%,slight toxicity), alkali-activated geopolymers reached 89.4%(non-cytotoxic), exhibiting a better biocompatibility. The biocompatibility and antimicrobial properties of the new resin need to be further studied. These results confirmed that geopolymer-modified nano-zinc resin has good biocompatibility, especially alkali-activated,having a possibility for clinical application as an antibacterial novel resin.