Periodic Reporting for period 3 - Living Bionics (Living bioelectronics: Bridging the interface between devices and tissues)
Período documentado: 2021-05-01 hasta 2022-10-31
However, the electrodes in these invasive devices used to stimulate or record the nervous system are made of stiff, inorganic materials like metals. The body recognizes these as foreign objects and attempts to protect itself from the implant by inducing an inflammatory response. Immune cells create a capsule, called a glial scar, around the electrode to isolate it and neural cells move away from the area. Consequently, higher, unsafe currents are needed to activate the nervous system and produce a therapeutic response, and the device may fail in the long-term.
In order to create a neural implant that is truly integrated by the body rather than tolerated, softer, organic materials are needed at the interface with the nervous system. The Living Bionics project aims to combine concepts from tissue engineering and regenerative medicine together with bionic device technologies to develop living bioelectronics: layered electrodes incorporating living cells encapsulated within a soft hydrogel to interface with the nervous system without eliciting a strong adverse immune reaction.
The objectives of this project include:
- Engineering a hydrogel that can support the growth of a neural network within it,
- Understanding the effect of biological, electrical, and environmental cues on the cells and their capacity to create connections,
- Implanting the resulting device in mice to show viable connections between the cells within the device and the host nervous tissue.
The Living Bionics project will be a ground-breaking step towards safer, truly integrated neural implants, paving the way for breakthrough therapeutic treatments for many widespread neural conditions.
As a result the team developed a novel material, PVA-Norbornene-gelatine (PVA-NB-GEL), and characterised its mechanical and electrical properties. In the second phase of the project, it was demonstrated that this hydrogel can support the growth of neurons and astrocytes encapsulated within it, and that these encapsulated cells can form functional connections with explanted brain tissue.
Based on these findings, the team designed and characterised a novel synthetic hydrogel and demonstrated that encapsulated neural cells can grow within it and develop active synapses with brain slices placed on top of the gel.
The project will now focus on producing the full layered device for implantation in mice where the functionality of connections between the encapsulated cells in the hydrogel and the neural tissue of the host will be investigated, along with chronic response to the device.