Femtosecond-laser-structured nitrocellulose membranes for multi-parameter Point-of-Care tests

• A novel fabrication method for cheap point of care–tests is presented.
• Laser-ablated hydrophobic barriers guide test liquid in nitrocellulose membranes.
• Ablation of nitrocellulose membranes with fs-Laser pulses.
• Integration of complex multiparametric detection in a small device footprint.

Cheap and disposable Point-of-Care diagnostic devices are of great interest to combat the rising cost of healthcare in industrial nations but also for a widespread use in the developing world. Paper based microfluidic devices as well as well-established lateral flow tests (LFTs) are both well suited for this role. However, they share various disadvantages including restricted reproducibility for quantitative readouts and are in most cases limited to a single parameter per test. In order to address these drawbacks we present a novel laser fabrication method for multi-parametric lateral flow tests based on nitrocellulose membranes. Using a femtosecond laser the membrane can be structured into barriers and channels which separate and guide the test liquid. By varying the laser parameters the presented method allows the rapid area-selective ablation of the entire membrane-thickness to the polyester backing thus creating a barrier for the fluid transport as well as a much finer, but slower, removal of the membrane material which leaves the membranes pore structure and fluid transport characteristics intact. With barrier and channel widths of 100 μm and 300–600 μm this process enables the integration of complex multi-parametric detection fluidic networks in the footprint of commercially available LFTs.

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