Akhilesh Gaharwar1
Texas A&M University1
Flexible electronics require elastomeric and conductive biointerfaces with native tissue-like mechanical properties. The conventional approaches to engineer such a biointerface often utilize conductive nanomaterials in combination with polymeric hydrogels that are crosslinked using toxic photo-initiators. Moreover, these systems frequently demonstrate low signal accuracy, poor biocompatibility and face trade-offs between conductivity and mechanical stiffness under physiological conditions. To address these challenges, we introduce a class of shear-thinning hydrogels as biomaterial inks for 3D printing of flexible bioelectronics. These hydrogels are engineered through a facile vacancy-driven gelation of MoS<sub>2</sub> nanosheets and naturally derived polymer. Due to shear-thinning properties, these nanoengineered<sub> </sub>hydrogels can be printed into complex shapes that can respond to mechanical deformation. The chemically crosslinked nanoengineered<sub> </sub>hydrogels demonstrate twenty-fold rise in compressive moduli and can withstand up to 80% strain without permanent deformation, meeting human anatomical flexibility. The nanoengineered network exhibits high conductivity, compressive modulus, pseudo-capacitance and biocompatibility. The 3D printed crosslinked structure demonstrate excellent strain sensitivity and can be used as wearable electronics to detect various motion dynamics. Overall, the results suggest that these nanoengineered hydrogels offer superior mechanical, electronical, and biological characteristics for various emerging biomedical applications including 3D printed flexible biosensors, actuators, optoelectronics, and therapeutic delivery devices.