An ordinary, aluminium, Nespresso-type coffee capsule has been transformed into a home test device for COVID-19 at Wageningen University & Research in the Netherlands.
The ‘CoronaEspresso’ is the brainchild of Dr Vittorio Saggiomo, Assistant Professor of the BioNanoTechnology group (BioNT0 and has been created in collaboration with the Netherlands Organisation for Applied Scientific Research (TNO). The test responds to the growing demand for decentralised COVID-19 testing methods.
“Centralised testing is only useful and feasible in terms of capacity to a certain extent,” Saggiomo explained.
“There were no good alternatives available for more efficient and effective decentralised testing.”
Dr Saggiomo also observed that current home testing methods are testing for antibodies, rather than antigens. While antibody tests work well with high virus concentrations, he raised concerns that people with lower virus concentrations can receive a negative test result.
“Furthermore, antibody-type tests can only be used once and then they are discarded. That is exactly what we do not want.”
Dr Saggiomo is an advocate for the LAMP (loop-mediated isothermal amplification) test. Like the well-known PCR (polymerase chain reaction) test, the LAMP method tests for the presence of an antigen, however, the LAMP test is cheaper, less demanding in terms of laboratory infrastructure, and yields faster results.
The CoronaEspresso can handle both LAMP and PCR tests. To do so, a paraffin-based phase change material is placed inside the capsule, which is then covered with a 3D-printed sample holder with enough space to hold four test samples at once.
The entire unit is then placed in water just come off the boil for 30 minutes. The paraffin warms the samples to 65 degrees and keeps them at that temperature for 25 minutes. According to the researchers, this allows a ‘LAMP reaction” to occur. The result can then be read from a colour change in the samples.
“The thin aluminium is perfect for the small increase of temperature for the amplification reaction to happen,” said Saggiomo, another big plus is that the test result can be determined without the need for another lab.
The CoronaEspresso is reusable, recyclable, and inexpensive. Nespresso-style capsules are already massively produced and easy to recycle because of the aluminium. The phase-transition material, which is not dissimilar to wax, can be used in candles and other items, and the 3D-printed holder is biodegradable – ultimately, the CoronaEspresso is not a single-use tool.
Able to be used for any RNA/DNA detection using LAMP, the BioNT has now made hundreds of CoronaEspresso tests. It has been successfully tested with synthetic SARS-CoV-2 RNA and with real human samples and has been proven to be a reliable indicator of the presence or absence of the virus.
Dr Saggiomo concluded that moving forward there could be scope to partner with coffee capsule brands to produce CoronaEspresso tests. In the meantime, he and his team are focused on optimising the sampling and the practical matters regarding LAMP reaction mixtures.