Biocompatibility of Asiga Dental Resins Using a Low-Cost Printer for Biohybrid Actuator Applications

Biohybrid actuators and robots require the integration of biological materials with synthetic materials. Synthetic materials provide structural support and attachment points for biological materials. One technique for fabricating these synthetic support structures is 3D printing. Although some 3D-printable resins have been designed to be biocompatible, the process for assessing biocompatibility is not reported consistently. Furthermore, the ISO 10993-1 standard emphasizes that biocompatibility must be evaluated based on specific use cases. Therefore, for biohybrid actuator applications, two commercial Asiga dental resins, DentaGUIDE and DentaGUM, were printed using a low-cost, LCD resin printer (Phrozen Sonic Mini 8K) and analyzed for their biocompatibility with C2C12, a muscle cell line commonly used in biohybrid actuators. C2C12 cells were cultured in direct contact with resin samples for 72 h, and their viability was examined using ethidium homodimer-1 and calcein acetoxymethyl ester (calcein AM), fluorescent dyes that mark dead and live cells, respectively. The ratio of calcein AM to ethidium homodimer 1 (CalAM:EthD-1) fluorescence was significantly larger for cultures exposed to the autoclaved (4,941±1,122) or ethanol-sterilized (3,783±683) DentaGUIDE samples as compared to the ratio for cultures exposed to polydimethylsiloxane (PDMS) (autoclaved: 1,940±989, ethanol-sterilized: 345±446). The CalAM:EthD-1 ratio measured in cultures exposed to DentaGUM (autoclaved: 43.67±9.38, ethanol-sterilized: 101.7±86.0) was significantly lower than the ratio found for autoclaved PDMS. This analysis suggested that DentaGUIDE has little to no impact on the health of C2C12, but DentaGUM negatively impacted the culture. Therefore, DentaGUIDE could be a suitable rigid material choice for biohybrid actuators.