To be confirmed

Type 2 diabetes is one of the most prevalent chronic conditions currently treated by the NHS, a common complication of diabetes is diabetic neuropathy, in which poor control of blood sugar levels over time can cause damage in the small nerve fibres of the extremities (usually the legs and feet) which can lead to diabetic foot ulcers. Ulcerations cause thousands of lower leg and foot amputations to be carried out every year by the NHS, significantly reducing patient quality of life. One of the main reasons that this procedure is so common is that there is no easy way of detecting the loss in small nerve fibre function caused by diabetic neuropathy. In many cases there is no pain associated with the loss of nerve function and patients are unaware that they have neuropathy until ulcerations occur, after which time an amputation is often the only option. This project aims to provide that early warning diagnostic system with an easy to use medical device capable of detecting reduction in nerve function in a GPs or hospital clinic. Surface electrodes currently used for detecting nerve function in hospitals are not applicable in this case as the small signals produced by the target nerves are attenuated (blocked) by the tough outer layer of skin. This project proposes to create a non-invasive microneedle array capable of painlessly penetrating this top skin layer in order to take high quality neural recordings.

Microneedle arrays are currently produced cheaply for drug delivery and biosensing applications. However, as they are not intended for recording small electrical signals they are constructed from a solid block of conductive polymer, so readings cannot be taken from each needle individually. A novel method of production in which each needle is electrically isolated must be developed to achieve recordings with a high enough spatial resolution to detect and isolate the small nerve fibre signals associated with neuropathy. For the project to be a success the product must also be translatable to a clinical setting, meaning it must be disposable, fully biocompatible, be able to be sterilised, and must have a sufficiently low unit price to be ordered in mass quantities by the NHS. To keep unit costs low, manufacturing methods used must be simple (i.e. not produced using standard silicon clean room fabrication as is currently used in most neural recording devices).

Low power CO2 laser ablasion will be used to machine a custom mould for the microneedles to align with the vias (small openings) of a flexible PCB also to be designed as part of the project. Conductive polymers will then be drawn through the vias using vacuum moulding alongside a masking/isolation process yet to be developed, producing an array in which each needle can be recorded from separately. A benchtop system will then be designed and built to amplify and process the signals recorded by the array and produce a useful output for a clinical setting. The final part of the project will involve testing the system on animal models and healthy humans to determine its safety and efficacy as a diagnostic device.

This project aligns closely with the EPSRC clinical technologies research area, particularly optimisation of diagnosis and treatment, and reflects its cross disciplinary focus. Supervision is being undertaken jointly between the School of Electrical Engineering and the Translational and Clinical Research Institute and includes a consultant neurophysiologist, the intended final user of the device. Additional input and guidance from the medical physics department at the Royal Victoria Infirmary will help to maintain focus on industrial uptake of the device due to their experience with the process of translating devices developed in the university to ones used in hospital clinics.