Injectable nanoelectrodes for wireless and minimally invasive neural stimulation

Project Information

NANeurO

Grant agreement ID: 101115997

DOI

10.3030/101115997

EC signature date 8 September 2023

Start date 1 November 2023

End date 31 October 2028

Funded under

• European Research Council (ERC)

Total cost

€ 1 499 725,00

EU contribution

€ 1 499 725,00

Coordinated by

TECHNISCHE UNIVERSITAET MUENCHEN
Germany

Periodic Reporting for period 1 - NANeurO (Injectable nanoelectrodes for wireless and minimally invasive neural stimulation)

Reporting period: 2023-11-01 to 2026-04-30

Summary of the context and overall objectives of the project

Neural devices used in the brain and spinal cord have yielded medical breakthroughs to improve the lives of people with spinal cord injury, Parkinson’s disease, and hearing loss. However, current neural devices are large, complex, and invasive, and are therefore used by only a fraction of people who could benefit from them. Instead, we want to make neural devices that are nanoscale, injectable, and wireless. By lowering invasiveness and implantation risk, this technology could address the unmet medical needs of more people with neurological impairments. The goal of NANeurO is to develop a minimally invasive nanoelectrode system capable of wireless, spatially selective, and multiplexed neural stimulation. We have previously developed nanoelectrodes that directly stimulated (i.e. with no genetic/biochemical neuron modification) the deep brain of mice as a proof-of-concept. This was possible because, unlike other wireless neural technologies, device powering was nonresonant, and thus independent of size. In the scope of NANeurO, we will now develop optimized nanoelectrodes, and will approach this by developing a toolbox of nanomaterials to study and learn from. In particular, we will look at how nanoelectrode size and shape affects signal/response and neurostimulation. This approach will generate new, enabling technologies, such as the ability to individually stimulate some particles while ignoring others, for multiplexed stimulation control. While the field of nanoscale and wireless neuroelectrodes is exceptionally small, new, and high risk, the proposed work could one day enable minimally invasive, wireless neural modulation.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The research progress is currently on schedule, and in some cases slightly ahead of schedule, with respect to the listed aims and milestones. We have already created a library of approximately ten cobalt ferrite (CFO), magnetostrictive (MS) nanoparticles. These are primarily still spherical, but have a range of magnetic behaviors. We hope to expand our library to include various shapes during the next phase of our project. All MS particles that we have made to date characterized chemically and magnetically. The MS characterization method is still in progress, with a collaboration via the TUM ZEIT lab established to use Focused Ion Beam (FIB) characterization to carry out these measurements. Therefore, the MS particles have not yet been characterized in this manner. Milestone 1, in which at least five MS particles have been synthesized and characterized, is fully achieved, with the exception of the MS characterization. The model we proposed is also running, and we will be submitting a manuscript to share the results in spring 2026. Milestone 2, in which we can back-predict properties, is not yet achieved (however, this was targeted for later than this reporting period). We plan to submit a manuscript characterizing these first particles in summer of 2026.
We have generated more than one barium titanate (BTO) coating protocol, and completed chemical, magnetic, and magnetoelectric characterization (more on the latter below). As the direct MS measurements are not yet up and running, we have not directly shown that the coating protocol alters the MS behavior of the CFO core particles. However, we have used an indirect way to predict this. In short, we normalize the CFO-BTO magnetic VSM curves using the mass ratio of the two phases to the same curve with just CFO. Any changes in MS behavior would also reflect changes in magnetic behavior, and in this way we can show that the CFO MS behavior is unchanged. Of the BTO coating methods we have used thus far, none show a change. Therefore, we have also achieved Milestone 3, but will continue to explore additional coating protocols. We have changed our ME measurement strategy from a piezoforce microscopy (PFM) method, to a new method, and we have successfully characterized the magnetoelectric (ME) behavior of a few ME nanoelectrodes. We are working on streamlining and expanding this to characterization of additional particle batches. We plan to submit this work for publication in spring 2026 as well. Thus, Milestone 4 is not completely achieved, but we are past the proof of concept stages of this work.
We have begun to establish our cell culture and calcium imaging protocols, but we are not at the nanoparticle testing stages yet.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

These will be released upon publication of a patent that details new methodology generated by the project.