2019 Nanoparticle reservoirs for paper-based biosensors

The performance of lateral flow immunosensors is restricted by their rigid 2D design. 3D Paper-based analytical devices can overcome this problem and enable new features such as the detection of many target molecules simultaneously or the reduction of manufacturing costs. However, it is difficult to store reagents such as nanoparticles in devices made solely of paper. This technology solves this problem. Their immunosensors contain reservoirs for storing antibody-decorated nanoparticles in the same filter paper. Folding the paper allows the easy transfer of reagents to different parts of the test without using pumps or syringes.

The specific capture of the target molecule or pathogen generates colored spots thanks to the excellent optical properties of gold nanoparticles. The colored spots can be detected with companion of apps for android, also developed by the research team. The apps only require hovering a smartphone over the assay to quantify the color in real time.

Prototypes for the detection of the cytokine IL-6 at clinically relevant concentrations in blood and in less than 17 minutes have been demonstrated. Disposable tests for detecting urine infections by E. coli in less than 7 minutes have also been developed.

The Rapid Diagnostic Tests (RDTs) developed are easily adaptable to other targets by tuning biosensor design.