(437c) A Biocompatible Conductive Ink for 3D Printing of Flexible Electronics

3D printing owing to its robustness, cost-effectiveness, and the high resolution is an expanding technology for developing functioning electronic circuitry out of semiconductors and other materials. They are also refining ways to combine electronics with biocompatible materials and even living tissue, which could pave the way for exotic new implants. Designing the new bio-ink is extremely challenging. For bioelectronics devices, bio-ink materials should be printable, strong enough to maintain its shape when immersed in nutrients or being under pressure, flexible, conductive and not harmful to the cells. Several flexible conductive bio-inks have been developed over the past years based on composite pastes containing a biopolymer and the conductive micro- and nanoscale materials in the form of metallic particles, conducting polymers, or a mixture of them. Herein, we report a new strategy for the fabrication of a bio-ink for commercial 3-D printer with excellent conductivity, superior mechanical properties, and good biocompatibility by using poly(glycerol-co-sebacate) based polymer and zinc. PGS based polymer and Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photoinitiator was added to the zinc and then the prepared bio-ink polymerized during 3-D printing under visible light. According to microstructural investigation by scanning electron microscopy (SEM), the zinc particles homogeneously distributed in the matrix PGSA, endowing the bio-ink with high conductivity. With regards rheology tests, the appropriate printable composition is 60 percent of zinc and 40 percent PGS based polymer. This bio-ink exhibited remarkable mechanical properties in comparison with PGS based polymer without zinc according to tensile and compression modules. In vitro results show that the bio-ink does not appear to be cytotoxic to the cells over a period of culture.