Recording or modulating biopotentials in living systems typically requires arrays of microelectrodes. Electrodes are conceptually simple devices consisting of a metallic conductor embedded in an insulating material [1]. At one end, a portion of the conductor is exposed and contacts the biological system, at the other it is connected to equipment that records or generates electronic signals. When many electrodes are integrated on a substrate, an array is formed where multiple contact sites establish a spatially defined interface. Electrode arrays have application in implantable bioelectronics such as neuroprostheses or for interfacing cells in culture.
Recently many efforts have focused on introducing soft (e.g. conductive polymers, composites) and even hydrated (e.g. hydrogels) materials in the construction of electrode arrays. This approach shows promise for improving the biointegration and delivery of electrical charges from the bioelectronic device.
In this talk I will discuss our efforts to utilise multi-material additive fabrication (3D bioprinting) for on demand writing of electrode arrays using soft materials [2]. The range of materials comprises silicones, conductive composites and hydrogels which can be processed with sub-millimeter resolution. Deposition relies on well-known approaches such as direct ink writing and inkjet printing but also on less known techniques such as electroassisted gelation [3][4]. Using these approaches electrode arrays that are stretchable and multimodal are realised.
Literature:
1. Afanasenkau, D., et al., Rapid prototyping of soft bioelectronic implants for use as neuromuscular interfaces. Nature Biomedical Engineering, 2020. 4(10): p. 1010-1022.
2. Athanasiadis, M., et al., Printed elastic membranes for multimodal pacing and recording of human stem-cell-derived cardiomyocytes. npj Flexible Electronics, 2020. 4(1): p. 16.
3. Da Silva, A.C., J. Wang, and I.R. Minev, Electro-assisted printing of soft hydrogels via controlled electrochemical reactions. Nature Communications, 2022. 13(1): p. 1353.
4. Da Silva, A.C., et al., Electrically Controlled Click-Chemistry for Assembly of Bioactive Hydrogels on Diverse Micro- and Flexible Electrodes. Macromolecular Rapid Communications, 2022. 43(23): p. 2200557.
