Global health applications of cell-free extracts for rapid, low-cost, paper-based diagnostics


Diseases and conditions like HIV/AIDs, vitamin deficiencies, and arsenic poisoning, result in high death rates in certain areas of the world. Crop and animal diseases can ruin domestic livelihoods. Deaths from many of these diseases and conditions could be prevented by accurate and accessible diagnostics. Unfortunately, in many parts of the world, diagnosing illnesses becomes problematic. The results may be incorrect as a result of contamination or improper technology use, or the technology may simply not be there at all. The Development i-Team’s project explored how synthetic biology research that allows rapid, low-cost, and paper-based diagnostics could revolutionise the accuracy and availability of detecting diseases in developing countries.

This technology is based on synthetic designed biological circuits, which can contain a sensor for a wide range of signals, from chemical to biological triggers. In the past, these genetic circuits were expressed in bacterial cells. However, recent developments have allowed the genetic extracts to be used without cells, and be freeze dried to paper strips. Because there are no living organisms involved, the regulatory hurdles that surround genetically modified organisms are overcome, whilst ensuring that genetic circuits remain flexible. The tests are stable and have a year-long shelf life, and the results are simple to understand.  This technology has already been proven for certain applications, such as the presence of Ebola and Zika viruses, and heavy metal pollution.

The i-Team identified six main areas where rapid, cheap, and easy diagnostics might be helpful:

  • human disease (eg HIV/AIDs, malaria, schistosomiasis)
  • nutrition (eg iron and vitamin A deficiencies)
  • animal disease (eg Newcastle disease, foot and mouth)
  • environmental contaminants (eg arsenic, coliforms, and mercury)
  • crop disease (eg Cassava Brown Streak Disease)
  • and in disaster relief (eg water contamination)

The team identified sensitivities and specificity limitations which can make healthcare applications difficult and were quick to establish that the use of the results needed to be diligently controlled and managed. And even though tests could be produced on-site, legislation and litigation could be problematic depending on where the technology is implemented.

In some areas, the team would need support from other groups to pressure governments or firms to fix the problems. These networks exist in India and South Africa, but it is unclear in many other countries. Affected communities can do the tests, but often they cannot afford them and would need external aid. This might come from unions or from the community, or from NGOs or governments. Going via not-for-profit organisations means that the team could use existing distribution networks, and could be viable as the tests can be manufactured at very cheap costs. In their for-profit strategy, the technology could be used in western world for education, and sold at higher cost. Finally, developing the technology using a charity could support scientists creating their own circuits, but they wouldn’t be able to trade.

To move the project forward and take the technology to market, the technology would have to be verified for its applications, and partnerships for manufacturing and effective distribution need to be established.

A start-up company called OpenDiagnostics has developed as a result of insights from the project. They were finalists in the Cambridge University Entrepreneurs social enterprise stream. This venture is part of the CGE Cultivator.

i-Teams website link:

Global health applications of cell-free extracts for rapid, low-cost, paper-based diagnostics