Multidimensional large-scale, high-density in vitro recording facility for the investigation of neural systems function

Lead Research Organisation: Newcastle University
Department Name: Biosciences Institute

Abstract

Neural function in our central nervous system arises from complex interactions between different neuronal types within vast neural networks.

To understand how these networks operate, simultaneous recordings from large neuronal populations are essential. This can be achieved ex vivo (for example in brain slices) using either imaging (to visualise fluorescent markers expressed in various cell types), or arrays of electrodes (multielectrode arrays; MEAs) that record electrical activity simultaneously from hundreds to thousands of neurons that are functionally connected to each other (or combining both approaches).

When using brain slices, surface cells are damaged because of the slicing process that disrupts the integrity of their cellular processes. For that reason, these recordings are normally done in the depth of the tissue with penetrating electrodes or with optical recordings.

Traditional MEAs consist of planar electrodes that can record only from the surface of the tissue. They are useful to record from cells in dissociated cultures, growing on the electrodes, or from the isolated retina, where the output cells form a single superficial layer. But these planar MEAs are not amenable to record from brain slices. Most MEA systems currently on the market with penetrating electrodes are too large for delicate isolated neural tissue, and they are limited to having no more than 100 electrodes, which is insufficient to analyse the network dynamics that we aim to study in the related projects we propose..

With this proposal, we aim to establish a facility around a unique next-generation MEA system consisting of 4,096 densely packed electrodes, allowing recordings spaced at similar distance to that between adjacent neurones in neural networks. These electrodes consist of pillars that penetrate the tissue and can therefore record neural activity in depth, where cells are not damaged and neural networks are intact. We will combine this cutting-edge new recording system with a fluorescent microscope that will allow us to perform concurrent imaging of various physiological parameters while neurons signal to each other.

This novel platform will allow us to study neural function in health and disease at macroscopic scale in health and disease using brain slices, retinas (from rodents and human tissue) and human stem-cell-derived artificial organs (retina, inner-ear).

We expect that this new facility will attract exciting new collaborations and technology developments in Newcastle.

Technical Summary

We seek funding to establish a unique, next-generation, multimodal platform for the in vitro study of brain function. The platform combines a large-scale, high-resolution multielectrode array (MEA) system with thousands of 3-dimensional (3D) electrodes with epifluorescence imaging to allow the study of neural network function at multiple scales in health and disease.

A significant limitation of current high density MEAs for in vitro neurophysiology is that they have arrays of planar electrodes. Such arrays can only record cells located superficially within the tissue, or in dissociated neuronal cultures, that come into direct physical contact with the electrodes. This is a serious disadvantage since cells in brain slices close to the cut surface may be damaged.

The MEA system (BioCAM DupleX from 3Brain) consists of 4,096 pillar electrodes capable of penetrating the tissue, thus allowing sampling of in vitro networks that is unparalleled in its extent and resolution. The pillars are 65 micrometer high, on 15 micrometer pedestals separated by microfluidic channels, allowing very efficient perfusion with physiological solutions under the tissue, which significantly improves its viability. The electrode pitch is 42 micrometers, close to cellular resolution in neural networks.

The MEA system will be combined with a high-speed widefield imaging system (Zeiss AxioExaminer Z1), an upright, fully motorized, fixed-stage microscope adapted for electrophysiology. The BioCAM DupleX consists of a small enclosure that can easily be positioned under the microscope. The microscope will be equipped with an environmental chamber, allowing us to perform prolonged recordings with organotypic cultures or organoids.

This novel, state-of-the-art experimental platform will allow us to investigate neural networks at multiple scales and unprecedented spatiotemporal resolution, shedding new light on neural network function in health and disease.

Planned Impact

To understand brain function, it is imperative to know how neural networks function both at subcellular/cellular and systems levels. The cutting-edge experimental platform we seek to build to investigate neural networks' function will have impact at several levels.

The immediate impact will be on the scientists directly involved in the project, as outlined in the Case for Support, and their groups. Indeed, the new experimental platform will provide invaluable tools, allowing these groups to reach much more insightful knowledge about the intricacy of neural function. Once familiar with the new instrumentation, the various groups will begin to generate and analyse new data and they will be able to train new users (new group members, short- or long-term project students, technicians). The project will bring great benefit to the scientific officer for capacity building in this group of highly skilled professionals who are important to keeping the UK at the forefront of technological development.

The named collaborators in this proposal will also be able to enhance their research output by using the platform, and hopefully will be able to replicate it in their own universities. Group members will present the results at local seminars, workshops, national and international conferences and will publish them in appropriate scientific journals. This will raise the awareness of the broader scientific community, leading to wider recognition and new collaborations, raising the external impact. Producing new, impactful results will facilitate future grant applications, allowing important future scientific investigations, for the benefit of science in the UK and abroad.

The platform will also foster important collaborations with technology developers, more specifically people involved in lab-on-chip technologies. These include academic collaborators (e.g. Dr Zagnoni, Strathclyde University) and industrial partners (e.g. 3Brain). With these collaborators, we hope to be able to contribute to the development of better recording devices. With time, we expect our circle of technology developers to grow.

In terms of industrial partners, in addition to chip technology developers, we also expect to produce important developments in stem cell science with NewCells, one of our project partners, and with time, we anticipate to form new collaborations with other companies interested in tissue engineering, neurotoxicology/pharmacology and stem cell approaches.

We expect the scientific output generated with the new platform to have important impact on 3R's driven scientific research and policies. Indeed, it will showcase how reduced, in vitro preparations such as brain slices or organoids (human organs in the dish) can produce meaningful results for systems biology, providing extremely rich and insightful datasets that traditionally would have been possible only by performing in vivo experiments, at a much larger scale.

We also expect that the scientific output generated with our new experimental platform will have societal impact by providing novel approaches to understand how various neural systems function in health and disease. This will be communicated to the wider public during science festivals, the Brain Awareness Week, patient interest groups etc.

Publications

10 25 50
 
Description This was an award for establishing a new multiuser experimental platform that combines electrical and optical recordings from the nervous system in vitro.
From my own group's point of view, this facility has so far been a fantastic resource, allowing us to visualise cellular activities in the neonatal retina at a unprecedented resolution and scale.
Exploitation Route The facility is now fully integrated in the BioImaging Unit of the Faculty of Medical Sciences and attracts many users
Several people have been using it to generate pilot data to get further funding from various sources.
We hope to start attracting external users (including companies) soon
Sectors Pharmaceuticals and Medical Biotechnology

Other

URL https://www.ncl.ac.uk/bioimaging/flamefacilitymedicalschool/
 
Description Characterising the angiogenic role of transient neonatal retinal cells
Amount £330,319 (GBP)
Funding ID RPG-2022-061 
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2022 
End 11/2025
 
Description closeNIT network
Amount £99,911 (GBP)
Funding ID NU-010513 
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 06/2024 
End 07/2025
 
Description Grant award to CloseNITs network 
Organisation University of Edinburgh
Department School of Informatics Edinburgh
Country United Kingdom 
Sector Academic/University 
PI Contribution This new project is UKRI funded, by the CloseNIT network (https://research.ncl.ac.uk/close-nit/) under the leadership of Prof Andrew Jackson. The grant was awarded in December 2023, and the work is going to start in July 2024, for one year. In this project, we will investigate whether there are specialised cells in the neonatal retina that act as pace-maker to generate spontaneous waves of activity during early development, while blood vessels develop. We will use closed loop stimulation paradigms to find these cells. This will be done using the multiuser facility awarded to me (as PI) in 2020 by the BBSRC
Collaborator Contribution We have partners both in Newcastle (Dr Luke Bashford, PI) and in Edinburgh (Prof Matthias Hennig, School of Informatics) They will contribute the computational aspect of the work, developing complex analysis stimulation and analysis paradigms to fulfil our goals.
Impact Not yet
Start Year 2024
 
Description Organising a Physiological Society meeting in Newcastle that will showcase our multiuser equipment facility 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact This is a neuroscience meeting that will happen in exactly one month in Newcastle University.
It i about neuroplasticity, with a strong emphasis on neurotechniques, showcasing our multielectrode array-imaging facility funded by BBSRC in the 19ALERT round
We got financial sponsorship from 3Brain as well; it is the company that manufactures the multielectrode array system. somebody from their company is coming to the meeting and will showcase their equipment to participants.
Year(s) Of Engagement Activity 2024
URL https://www.physoc.org/events/neuroplasticity-in-brain-health-and-disease-advances-in-techniques-tra...
 
Description world wide web neuroscience presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact About 300 people attended a presentation on my research activities. This occurred during the pandemic, hence it was online, through the newly created worldwide web neuroscience resource
Year(s) Of Engagement Activity 2020
URL https://www.world-wide.org/seminar/920/