Soft implants as medical devices Researchers in the BIOELECTRIC project are working to develop a biocompatible, soft bioelectric implant that can secrete ions and molecules. This work could open up new possibilities in the treatment of a variety of medical conditions, as Professor Hagan Bayley explains. A lot of
communication in the body occurs through small molecules, such as hormones and neurotransmitters, or ions, such as chloride, sodium and calcium ions, which influence physiological processes by binding to receptors or affecting electrical activity. As the Principal Investigator of the EU-backed BIOELECTRIC project, Professor Hagan Bayley is working to develop a soft, bioelectric implant capable of secreting these molecules and ions in the body. “We want to make a device that can secrete molecules or ions in a spatially controlled manner, and be able to turn secretion on-and-off at will,” he outlines. Such a device holds wide therapeutic potential, for example in delivering therapeutics to accelerate wound healing or regenerate the spinal cord, yet Professor Bayley says the aim of the project is to develop a general technology rather than focus on a specific application. “We’re trying to devise a platform device that can be used for many different applications,” he says.
Synthetic tissues as implants This research builds on earlier work on a class of membrane proteins called protein pores, which can be used as sensors. A spin-off company, Oxford Nanopore, was established by Professor Bayley in 2005 to bring a platform sensing technology based on protein pores to the market. The company developed the MinION nucleic acid sequencer, while Professor Bayley and his colleagues at the University of Oxford moved on to pursue other avenues of investigation. “We took our interest in membrane proteins to make synthetic tissues. The idea was to use a 3-D printer to pattern tiny aqueous droplets with a volume of around 50 picolitres [2013 Villar]. We can get these compartments to communicate with each other by using protein pores,” he explains. “Living tissues comprise communicating cells and hence the printed materials behave as synthetic tissues [2019 Bayley; 2021 Alcinesio], which can be used as implants.” These materials are made using naturallyoccurring lipids to ensure biocompatibility, and then encapsulated in polymers to
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A 3D-printed structure formed of droplets. The blue droplets contain a small molecule, which can be secreted through protein pores in the pattern of a cross.
make the implants more robust. This is an important consideration when an implant is employed over a long period, although there are also possible applications where the implant might have a shorter lifespan. “For example, if we want to use one of these implants for wound healing then we would want it to be degraded by the body over a
The device works according to broadly the same basic principles in these two cases, but with refinements that are relevant to the specific application. It’s important to demonstrate that the technology can be used to solve specific problems if it is to be commercialised, but at this stage Professor Bayley and his colleagues are looking more
We want to make a biocompatible device that can secrete ions and molecules. Further, we’d like to control secretion, to turn it on and off when we want to. few days,” says Professor Bayley. The aim is to develop a flexible technology that can secrete different therapeutics and therefore be used in different applications. “If you want to treat a spinal cord injury, you might want a device that secretes peptide growth factors, while if you’re trying to accelerate wound healing, you might want to secrete a combination of antibiotics,” explains Professor Bayley.
generally to develop and improve the device, bringing together several strands of research. “We’re exploring several different ideas,” he says. One important issue in the project is to control the implants from outside the body, without the need for lots of wires or other paraphernalia. “If these devices are relatively near the surface of the body, then you will be able to control them with light. If they are implanted in an
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