Lecture
Skeletal muscle cells, used to actuate biohybrid, hydrogel-based actuators, require electrical stimulation in order to contract. However, most currently used biomaterials, e.g. in cardiac tissue engineering, lack electrical conductivity and appropriate mechanical properties. Both parameters are important for regulating skeletal muscle cell behaviour. Here, we show a 3D microchannel-containing, conductive polyacrylamide scaffold as it is a suitable matrix material for growing skeletal muscle cells . The scaffolds are based on open porous ceramic templates prepared from sacrificial zinc oxide (ZnO) tetrapods. These templates can be infiltrated with different dispersions including exfoliated graphene, graphene oxide or carbon nanotubes (CNT) dispersions. The infiltration process leads to a homogeneous coating on the ceramic network. Embedding these functionalized templates into polyacrylamide, and subsequent dissolution of the ZnO template results in a conductive, microchannel-containing hybrid hydrogel. Exfoliated graphene, reduced graphene oxide or CNTs are used to provide the required conductivity. Further, the stiffness of the scaffolds can be tailored to match the stiffness of native muscle tissue. MTT-assays have shown that the scaffolds have no negative impact on the cell viability. Additionally, the samples can be functionalized with cell adhesive proteins like RGD or collagen to enhance cell adhesion. The presented work illustrates the potential of microchannel-containing hydrogels as a first step towards the development of a biohybrid, hydrogel-based actuator.
