Cambridge Consultants is taking part in a $1m project to develop a device that uses a relatively new DNA amplification technique to provide a cheap and fast method of testing for Ebola in the field.
The product design and development company is working with US non-profit enterprise and molecular diagnostics specialist Diagnostics For All to develop the low-cost point-of-care device, using a grant from Massachusetts Life Sciences Center.
The goal of the project is to develop, produce and complete in field testing for the resulting technology within six months, producing a device that is simple to use and can deliver results quickly in areas where there may be little or no access to medical facilities or trained doctors, nurses and lab technicians.
To test for the presence of Ebola in blood, DNA from the virus needs to be extracted and replicated to amplify it, as there may not be that much of the virus in a single blood sample.
‘The test will extract the nucleic acid from the virus in a sample, replicate this and deposit the replicated nucleic acid onto a testing strip, where it can react with other ingredients to create a red positive line – if the person has Ebola – and a control line to show the device is working. It is similar to the process in a pregnancy test kit,’ explained David Chastain, programme manager at Cambridge Consultants.
At present, diagnosing Ebola is extremely challenging. It can be hard for patients in remote areas to get to a clinic to have their blood drawn – and the sample must then be transferred to a lab and tested by trained technicians. Once there, the current gold standard test for Ebola is the PCR (polymerase chain reaction) test. Invented in the 1980s, this involves cycles of heating and cooling a sample to create more copies of a piece of DNA, and the process takes several hours. By the time the results are produced and returned to a clinic – often hours or days later – the patient may have left or infected others.
However, the test under development uses loop mediated isothermal amplification (LAMP) technology, which depends on a simple electric heater within the unit to heat the sample to a single constant level, and does not require cycling of the temperature to produce results. It can be used outside of clinics by minimally trained workers on those who are showing symptoms such as fever, vomiting and diahorrea – symptoms that are also typical of other diseases common to Ebola infected areas, such as malaria.
‘We think that the Ebola virus sequesters in the spleen and liver and then comes out in force into the rest of the body later in the infection,’ said Chastain. ‘This makes it hard to detect earlier in the infection process. However, this test would let us separate the malaria and other patients from the Ebola patients, minimising the risk [of] infecting the first group with Ebola when they come to clinics.’
The test will cost less than $10, and will consist of a handheld, single-use disposable device that is smaller than a deck of cards. It will only require a health worker to prick a patient’s finger and directly apply a droplet of blood on to the device. Everything else needed to test the blood will be fully integrated inside the device and the entire process will be completed in 45 minutes.
‘It’s cheap, small and lo-tech,’ concluded Chastain.