Lab-on-paper for inexpensive medical diagnostics

Engineers from the University of Rhode Island have created a paper-based platform for conducting a wide range of complex medical diagnostics. Fluid-actuated valves, which are embedded in the paper, allow for the sequential manipulation of sample fluids and reagents in a controlled manner to perform complex immune-detection tests without human intervention.

In paper-based lateral flow test strips, such as pregnancy tests, the sample fluid wicks along a strip of paper, reacts with embedded reagents and produces a coloured signal result. However, more complex medical diagnostics such as enzymatic assay protocols require multiple reagents triggered at particular times during the process.

“We combined the well-established test strip technology, micro-patterning techniques and our innovative paper-based valves to create a new class of strip tests that are capable of autonomously handling multiple reagents,” said team leader Professor Mohammad Faghri. The lab-on-paper devices are constructed with multiple layers of paper printed with wax to create a 3D structure of valves and channels along which the fluid travels.

“The sample fluid activates the flow of reagents in a predetermined sequence and time,” said Professor Faghri. “When combined with an optical reader, which could even be a conventional smartphone, the lab-on-paper device provides accurate quantitative results.

“We’re the only research group in the world to have created fluidic valves on multilayered paper without the use of external mechanical, electric or magnetic force and to use these valves to create fluidic circuits similar to electrical circuits.”

Professor Faghri has established start-up company Labonachip with Professor Constantine Anagnostopoulos, who serves as the company’s president. Labonachip aims to commercialise the researchers’ technologies, with Professor Anagnostopoulos saying, “We’re looking to partner with medical or biological companies that have identified disease biomarkers or other molecules of interest for which we could develop tests for using our platform.”

The researchers have already performed a successful feasibility study by detecting a biomarker for sepsis, a life-threatening complication from an infection. Start-up company ProThera Biologics identified a biomarker that indicates a patient is going into shock from sepsis, and the company collaborated with Professors Faghri and Anagnostopoulos to develop a paper-based rapid test using the biomarker.

Professor Faghri said the technology has potential applications for a wide variety of medical diagnostics, in the veterinary medicine field and for the detection of environmental contaminants and biological or chemical threats.

“If someone comes up with a new biomarker for detecting a disease, we can create a test for it using our platform,” he said.

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