Metal-Organic Framework-Based Gas Sensors: Structural Engineering for Early Diabetes Diagnosis and Monitoring (SEEDDM)

Diabetes is a tremendous health problem with 537 million cases worldwide in 2021 and contributing to millions of deaths each year. The annual global health expenditure on diabetes is expected to reach GBP 876 billion by 2045. Spectroscopic technologies (e.g. gas chromatography and mass spectrometry), alternative to invasive glucose blood testing, still dominate the non-invasive breath analysis market for diabetes screening and monitoring, however, these technologies are relatively expensive, slow, complex and require specialist skills to use and to interpret results. In comparison to those techniques, nanomaterials-based sensors (e.g. metal oxide semiconductor (MOS)) provide advantages such as simple, sensitivity, small size, ease of operation, and minimum maintenance requirements. However, most of the MOS-based sensors require high operating temperatures (200-500 oC) resulting in high energy consumption. Furthermore, MOSs only allow limited discrimination between different gases (e.g. alcohols and ketones) which cannot be determined without specialised spectroscopic techniques. Therefore, the development on the nanomaterials have been motivated.

Metal-organic framework (MOF)-based materials are favourable due to their tunable pore sizes and shapes, high surface area, and nanopore structures, which allow easy diffusion of guest molecules into the highly-ordered frameworks, but the problems such as (mostly) their nonconducting characteristic, poor stability, unclarified and complicated gas sensing mechanism need to be solved, thus the innovation of structures for MOF-based electrodes calls for further exploration. The SEEDDM project will bring together internationally recognised researchers in heterojunction-based materials architectures and modelling from UM (Kuala Lumpur, Malaysia) and the expertise of UoE (Edinburgh, UK) in the development of porous nanomaterials to work on the conductive monolith metal-organic framework (MOF) coupled with suitable hydrogel electrolytes for breath (volatile organic compounds) VOC sensing in the applications of early diabetes diagnosis and monitoring. Our joint approach aims to solve the research challenges (synergy effects of conductive monolith MOF electrodes and hydrogel electrolytes to work at ultra-low power and room temperature environment) for the purpose of innovating inexpensive, portable, and high-performance devices. Diabetes biomarkers that could be detectable in breath are VOCs, which include acetone, isoprene, carbon monoxide, ammonia, and alkanes. Through collaboration with UM, state-of-the-art materials and device characterisation techniques will be used to understand the underlying mechanisms which will advance our ability to develop improved clinical decision, making personalised therapies combined increased levels of self-monitoring and diagnostics. The successful of this research will potentially ease the pressure of NHS on early diabetes screening and monitoring.

After successfully fulfilling SEEDDM, we aim to innovate a portable, non-invasive breath analyser that exhibits high sensitivity (e.g. 0.05-3 ppm acetone detection at room temperature), high selectivity of target gases (e.g. ketone, alcohol), fast T90 response time (the time consumed when the gas detector changes from reading 0 to 90% of the full scale gas concentration) less than 60s, and stable cycle of more than 1,000 redox cycles (>85% humidity). Medical monitoring devices and wearable health technology have seen rapid growth over the past years (£17.5 billion in 2021 to £162.6 billion by 2030, a CAGR of 28.1%). Therefore, SEEDDM will not only help advance the quality of healthcare research and innovative efforts in the UK and Malaysia, but also strengthen and stimulate the development of new technologies in the healthcare industry.