Bienzymatic Generation of Interpenetrating Polymer Networked Engineered Living Materials with Shape Changing Properties

The synthesis of a porous shape-changing interpenetrating network (IPN) bioink for the fabrication of large-scale (cm) reversibly thermosensitive structures is described. The poly(N-isopropylacrylamide) (PNIPAm) IPN is generated in situ within an ionically crosslinked alginate hydrogel at room temperature and under aerobic conditions using a horseradish peroxidase (HRP)/glucose oxidase (GOx) bienzymatic initiation system. Mechanical testing assessment of the IPN hydrogels confirm mechanical reinforcement via covalent single network interdigitation. Furthermore, the thermosensitive bioink can be used to print biohybrid reactors containing genetically engineered phosphotriesterase-expressing E. coli capable of hydrolyzing toxic organophosphorus compounds. Herein, increasing the bioink pore size using the contractile-thermosensitive response of the IPN improves the temperature-dependent theoretical mass-transfer-limited enzyme catalyzed reaction rate, providing a plausible route to externally regulated enzymatic catalysis within bioprinted structures.