Researchers have developed a 3D printing technique that extends the possibilities of lateral flow testing. Everyone is familiar with these tests in the form of the classic pregnancy test and the COVID-19 self-tests. With the new printing technique, advanced diagnostic tests can be produced that are quick, cheap, and easy to use.
Using a 3D printer, the researchers fabricated a 3D version of a lateral flow test. The basis for this is a block of porous polymer in which inks with specific properties are printed at precise locations. In this way, a network of channels and small locks is printed that block or let the flow through where and when it is needed, without the need for moving parts. During the test, the sample is automatically guided through the various test steps.
The researchers tested their technique using an ELISA test (enzyme-linked immunosorbent assay) to detect immunoglobulin E (IgE). IgE is measured to diagnose allergies. In the lab, this test requires several steps, with different rinses and a change in acidity. The research team was able to perform the full analysis on a printed test kit the size of a thick bank card.
The technique not only offers opportunities for cheaper and faster diagnosis in developed countries, but also in countries where the medical infrastructure is scarcer and where there is a need for affordable diagnostic tests.