PhD Research Project: Affordable Point-of-Care Lactate Sensor for Maternal Sepsis

Sepsis, which occurs when infection leads to life threatening organ dysfunction, is one of the main causes of maternal death, especially in low income countries (Say, 2014). Early diagnosis followed by timely intervention with the correct treatment is essential to reduce these preventable deaths, yet improving sepsis care has been relatively neglected by international efforts, and has only recently become the focus for action by the World Health Organisation and major international donors. (WHO Statement on maternal sepsis, 2017)

The measurement of lactate is part of the gold standard of sepsis care, and a key requirement of the American Surviving Sepsis Campaign guidelines and in the UK the NICE guidelines for sepsis. This marker helps clinicians detect sepsis rapidly, determines severity and guides subsequent management.

Amperometric/ electrochemical sensors are widely available for point-of-care lactate measurements, even now being used in the UK by paramedics and general practitioners, but the cost ~£1 per test, makes this test unaffordable for low income countries. Indeed we recently completed an international audit of sepsis resources, and found that in Malawi of the 36 health facilities audited it was only reliably available in 2 centres, and findings were similar in the other 17 low income countries surveyed.

The World Health Organisation maternal sepsis working group, of which we are part, has identified the lack of maternal lactate monitoring as a major barrier to the provision of high quality maternal sepsis care. Innovation to make this available in low resources setting, where there is the greatest need, is urgently required.


This PhD project will firstly investigate the sensitivity, limit of detection and dynamic range of lactate assay performed using the enzyme lactate oxidase and methylene green in cuvettes. Similar experiments will then be performed by introducing lactate solution on top of a hydrogel layer consisting of lactate oxidase and methylene green. The effect of storage conditions and type of hydrogel used on the activity of lactate oxidase will also be investigated. The porosity of the top hydrogel layer to both small molecules (e.g. lactate) and large components (e.g. red blood cells) will be deduced using dye solutions and 6-8 µm beads respectively. Subsequently, the two hydrogel layers will be deposited on top of each other and the resulting sensor will be tested in serum and then blood samples, spiked with lactate. Finally, the sensor will be tested using patient samples. The student will also have the opportunity to visit sites where the team are currently running maternal sepsis quality improvement studies at 13 health faciltiies in Malawi. There they will be able to understand the requirements of the device and gain feedback from future users.

PhD candidate specification:
In order to qualify for this studentship you need to hold or obtain a minimum of a good (>65%) upper second class or higher integrated UK masters (MSci/MChem/ MEng) degree or equivalent in physical sciences or engineering or a related subject. Students with a combination of a good UK or equivalent BSc/ BEng degree followed by an MSc with >60% in all taught elements will also qualify.

Funding Notes

This project is fully-funded by the University of Birmingham’s Global Challenges PhD Scholarship which includes full payment of tuition fees of £4,195 annually and an annual maintenance doctoral stipend at £14,553.