K.E. Whitener, Jr., W-Kg Lee, S.P. Yoseph, D. Haridas
U.S. Naval Research Laboratory,
Keywords: graphene oxide, inkjet printing, tissue engineering, bioelectronic interfacing
Summary:Techniques for interfacing electronic structures with biological systems are a critical capability required for advanced biological engineering. In most cases, biological entities cannot withstand the harsh processing required by electronics fabrication; thus, a method for transferring pre-built electronics onto cells is essential to overcome this roadblock. We recently demonstrated transfer of electronic structures to cells using single layer hydrogenated graphene (SLHG) as a support. However, in addition to its nontrivial synthesis, SLHG is just one atomic layer thick and therefore can only support electronic structures of limited mass before breaking apart. Also, adhesion of SLHG to a biological target substrate requires exposure to chemicals such as bromine gas that are incompatible with biological systems. To address these issues, we have now developed a transfer technique based on films of partially reduced graphene oxide (rGO) as the support layer. Graphene oxide (GO) is cheap, abundant, and simple to prepare and manipulate. We have prepared 1-50 nm thick GO films on glass or plastic and reduced the films via chemical or thermal pathways. We have shown that the rGO films delaminate readily in water, with dimensions up to 8 ½” x 11”. Concurrently, we have modified a commercial off-the-shelf inkjet printer to print metallic structures onto GO films and demonstrated their subsequent reduction and transfer. Finally, we have optimized the water-based rGO transfer to stem cells for film adhesion and cell viability. Our new methodology comprises a simple and inexpensive system for constructing on-demand electronic elements and transferring them to cells for use in biological engineering.