Microneedle integrated foetal scalp electrodes for neonatal brain monitoring

Approximately 8% of babies in the UK are born prematurely as per a report published by the UK National Screenings Committee in 2020(1). Neonates born prematurely are vulnerable to a wide range of illnesses such as hypoxic-ischemic encephalopathy (HIE), respiratory distress syndrome, cerebral palsy, sepsis, and even death. Preterm births are a significant financial burden to health systems(2). The current gold standard for foetal monitoring during labour is cardiotocography (CTG) which involves placing an ultrasound transducer on the mother's abdomen. The use of CTG has not shown a significant change in perinatal mortality, potentially preventable deaths, caesarean sections, or admission to neonatal intensive care units(3). Amplitude-integrated electroencephalogram (aEEG) is a routine brain monitoring technique used to detect HIE in infants, particularly during the first 48 hours post birth(4). A method of foetal brain monitoring during labour is desired, which can improve detection of HIE during childbirth to allow early medical intervention to prevent foetal/neonatal brain injury. The project will explore the development of microneedle based novel foetal scalp electrodes integrated with aEEG. Microneedles are a suitable option for foetal monitoring as these are minimally invasive, causing minimum to no pain as these penetrate only the superficial layers of skin and do not interact with pain receptors beneath the skin. Microneedle-based vaccine patches have already been tested successfully in infants(5,6). This project is funded by the GW4 Medical Research Council Doctoral Training Partnership; it is in the remit of the 'Mental Health and Neuroscience' core theme for the GW4 DTP. It also falls into their special interest themes of 'Prevention and Early Detection', and 'Interdisciplinary Research'.
Aim: The aim of this project is to develop microneedle-based scalp electrodes via additive manufacturing suitable for foetal monitoring during labour. In-house manufacturing facilities will allow for flexible and custom microneedle designs. 3D printed microneedle techniques can enable various functionalities such as enhancing signals or drug delivery(7,8). Microneedles will be optimised to enhance signals from integrated aEEG and foetal monitoring systems. Additional functionality for microneedles may be considered at a later stage.
Objectives:
a) Explore and select the optimum microneedle material, shape and array size for detection of signals. Experiment with various microneedle fabrication techniques using different equipment such as FormLabs 3D printer and the nanoprinter.
b) Work with supervisory team to integrate aEEG in the microneedle-based electrode, making use of proprietary electronics technology.
c) Explore materials for attachment to human scalp. Key considerations should include stability of placed prototype, robustness of design, adherence in conditions similar to labour.
d) Develop working prototype to test on healthy adult volunteers. Characterise prototype properties like strength, usability, lifetime etc.
References:
1. https://view-health-screening-recommendations.service.gov.uk/preterm-birth.
2. Chawanpaiboon S et al. Global estimates of preterm birth in 2014: systematic review. Lancet Glob Health. 2019;7(1):e37-46.
3. Grivell RM et al. Antenatal cardiotocography for fetal assessment. Cochrane Database Syst Rev. 2015;9(9).
4. Lemyre B et al. Hypothermia for newborns with hypoxic-ischemic encephalopathy. Paediatric Child Health. 2018;23(4):285-91.
5. Harris E. Microneedle vaccine patches generate immune response in children. JAMA. 2024;331(23):1982.
6. Adigweme l et al. Measles and rubella vaccine microneedle patch in The Gambia: randomised trial. Lancet. 2024;403(10439).
7. Keirouz A et al. Conductive polymer-coated 3D printed microneedles for biosensing. Small. 2023;19(14).
8. Turner JG et al. Hydrogel-forming microneedles: advancements and trends. Macromol Biosci. 2020;21(2):2000307.