Conductive polymer hydrogels combining tunable electrical conductivity and biomolecular affinity for multimodal in vitro stimulation

• Applicant: Dr. Christoph Tondera
• Subject Area: Biomaterials ; Synthesis and Properties of Functional Materials ; Microsystems ; Polymer Materials
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 518476867

Electroconductive polymers are increasingly used in novel bioelectronic devices to maximize conductivity and charge storage capacity, making them ideal candidates for electrical stimulation of electroactive biological tissues such as neural or cardiac tissue. In biological systems electronic and biomolecular signals are interconnected. Recapitulating this principle technologically in an electroconductive material with adjustable biomolecular affinity will enable electronic and biomolecular processes to be stimulated in a controlled and combined manner. However, this has not been achieved so far. To pioneer this approach, it is my main objective to design, characterise and apply a new class of conductive hydrogels. These materials consist of sulfated/sulfonated polymer hydrogels (SSPH). Importantly, the SSPH materials can be modified in their physicochemical properties and therefore, in their specific electrostatic affinity to biomolecules. The electroconductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is forming a semi-interpenetrating network within the SSPH. Since the variable sulfation degree and pattern of the SSPH functions as dopant for PEDOT, the electrical properties of the hydrogels can be tuned. Additionally, the positive charge of PEDOT can be adjusted electrodynamically by the application of electrical potentials leading to PEDOT:SSPH materials with adjustable biomolecular affinity. (1) To gain a comprehensive mechanistic understanding of PEDOT:SSPH materials, their electrical, structural and mechanical properties will be characterized under systematic variation of the physicochemical properties. (2) Furthermore, it will be investigated how the affinity of PEDOT:SSPH materials to biomolecules can be electronically controlled. For this purpose, the sequestration and release of biomolecules will be investigated using different PEDOT:SSPH materials and different electrical potentials. (3) The materials will be integrated into functional systems by developing specially adapted microfabrication techniques. (4) Finally, the established systems will be used to validate their multimodal functionality in vitro. This work will provide a material system that will enable unprecedented communication capabilities between living tissue and electronic devices for stimulation of electrical and biomolecular signals. In perspective, the approach is envisioned to further shift the boundaries of living matter and electronic devices.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Carsten Werner