THE AFRICAN CONTEXT
In many of the poorest countries, large proportions of the population do not have access to healthcare facilities with high quality diagnostics, and consequently healthcare provision is based almost entirely on empirical management, supported by a few rapid diagnostic tests for specific diseases such as malaria. In addition, it is extremely difficult to estimate the burden of diseases because of poorly performing health information systems.
Conventional diagnostic laboratories require costly infrastructure such as uninterrupted power supplies, clean water, supply chains for consumables, trained personnel, regular maintenance and quality control. It is currently unrealistic to establish such facilities close enough to every community in order to provide timely diagnostic testing for all, and especially among the poorest and most-underserved communities where there is a disproportionately high burden of disease.
It is currently unrealistic to establish such facilities close enough to every community in order to provide timely diagnostic testing for all, and especially among the poorest and most underserved communities where there is a disproportionately high burden of disease.
Digital diagnostics provide an innovative solution to this problem, with rapid, cheap, connected, point-of-care tests accompanied by decision support, essentially bringing the laboratory to the point of interaction between patient and health worker, and providing vital information for disease surveillance and control to national and international public health bodies.
Digital diagnostics have been hailed as the future of healthcare provision in resource rich countries, because of their potential to provide rapid and convenient diagnostic solutions, but digital diagnostics offer greatest potential benefits in African healthcare systems. In Africa, digital diagnostics could enable a model of care which completely removes the need for conventional diagnostic laboratories in all but major tertiary centres.
This would dramatically improve both case management, especially for those most marginalised from conventional diagnostics, and disease surveillance, which would allow for better targeting of resources and improved health systems, paving the way towards universal health coverage and achievement of SDG3.
DIGITAL MOLECULAR DIAGNOSTICS IN AFRICA
WHAT WE HAVE DEVELOPED
We have developed an innovative digital diagnostic platform called Lacewing, which we propose as solution for the development of digital molecular diagnostics for Africa. Lacewing is a cartridge-based, isothermal, electrochemical DNA biosensor (Fig. 1).
It allows the point-of-care detection of parasite DNA from a few microlitres of finger prick blood, with a detection time of 15-30 minutes.
Lacewing is coupled by Bluetooth to a smart phone app interface (Fig. 2), which provides data analysis, decision support, time and location stamping and up-load to a secure, cloud-based surveillance platform (Fig. 3).
We believe that Lacewing strikes the right balance between technological advance and suitability for application in resource limited-settings, occupying the sweet-spot for success of a digital diagnostic for Africa.
Lacewing utilises complementary metal-oxide-semiconductor (CMOS) microchips to detect the evolution of hydrogen ions during the incorporation of nucleotides into a growing DNA template (Fig 1). Exchangeable cartridges for different combinations of nucleic acid targets are configured by addition of different primers for highly-specific loop-mediated isothermal amplification (LAMP) reactions, allowing small quantities of nucleic acid to be rapidly detected in blood (and other body fluids) without the need for thermocycling, and for multiple targets
to be detected in parallel wells of the same cartridge. Using mass-produced electronic components minimises productions costs, and cartridges are expected to cost well under $5 when mass-produced.
Lacewing is developed by a team of researchers at Imperial College London, led by Dr. Pantelis Georgiou.