Point-of-care medical diagnostics technologies offer a fast and cheap way to help patients as they require no experienced personnel or expensive laboratory tests. Several innovations such as a DNA test chip and a biosensor that can detect viruses give us an idea of the possibilities in this field. Now a research team at the University of Rhode Island in the US has developed a paper-based platform that's claimed can perform complex diagnostics.

Paper-based test strips already exist and are used for pregnancy tests, for example. Typically, a sample fluid wicks along a strip of paper and reacts with embedded reagents to present a colored signal. But to produce more complex diagnostics, it is necessary that multiple reagents are triggered at specific times.

The new paper-based technology is a development of a lab-on-a-chip device from 2011, which was designed for fast blood tests. That device has been made smaller and now uses a micropump for precise fluid movement within the cartridge’s microchannels. This device helped in the development of the new lab-on-paper devices.

"The sample fluid activates the flow of reagents in a predetermined sequence and time," said lead researcher Professor Mohammad Faghri. "When combined with an optical reader, which could even be a conventional smartphone, the lab-on-paper device provides accurate quantitative results. It can perform enzymatic assays on paper autonomously with sensitivities close to laboratory techniques."

The architecture of the mini-lab is an essential feature. Multiple layers of paper printed with wax create a three-dimensional structure of valves and channels where fluid travels. This way they can trigger the reagents at the right time to produce a diagnosis. And unlike the team's lab-on-a-chip device, no external force of a mechanical, electric or magnetic nature is required to move the fluid through the channels, as this is achieved through wicking.

Using a biomarker identified by ProThera Biologics, Professor Faghri and colleagues have successfully tested the technology in a feasibility study designed to detect sepsis, a generalized inflammation caused by an infection that can lead to death.

In terms of application, the researchers say the platform is potentially very versatile. It could be used for a range of tests for such maladies as Lyme disease, HIV, Ebola, malaria, among others. The application of the method could also extend to the veterinary field as tests for environmental contaminants and chemical threats.

"If someone comes up with a new biomarker for detecting a disease, we can create a test for it using our platform," said Faghri. He and collaborator Constantine Anagnostopoulos, a URI adjunct professor of mechanical engineering, have founded a start-up called Labonachip LLC to commercialize the technology.

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