AI Insight
Researchers developed a silicone-based extrudable ink composed of vinyl-terminated polydimethylsiloxane and polymethylhydrosiloxane, crosslinked via platinum-catalyzed hydrosilylation and modified with silica fillers to achieve shear-thinning behavior suitable for extrusion printing. This ink was used to fabricate high-resolution hydrophobic barriers on paper substrates, enabling the production of microfluidic channels as narrow as 150 micrometers. The approach demonstrated improved fluid confinement, pattern fidelity, and enhanced sensitivity in a lateral flow assay designed for malaria diagnostics.
Why it matters
Paper-based diagnostic devices are critical tools for low-resource and point-of-care settings, and this fabrication method offers a simple, low-cost route to higher-performance tests that could improve disease detection in underserved regions. The scalability of extrusion printing makes this approach potentially compatible with large-scale manufacturing of diagnostics.
⚠️ Preprint – Noch nicht peer-reviewed
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Paper-based diagnostics such as lateral flow assays (LFAs) and microfluidic paper-based analytical devices (PADs) have attracted considerable attention because of their low cost, portability, and ease of use. Currently, to enable fabrication of PADs and improve LFA performance, hydrophobic blocks are patterned on paper substrates. However, fabrication of high-resolution hydrophobic barriers remains a major challenge. In this work, we developed a novel silicone extrudable ink for the fabrication of hydrophobic features on paper substrates. The ink was formulated using a vinyl-terminated polydimethylsiloxane (vPDMS) and polymethylhydrosiloxane (PMHS) system crosslinked through platinum-catalyzed hydrosilylation, and its rheological properties were tailored by incorporating silica fillers, obtaining a shear-thinning gel suitable for extrusion. The resulting formulation provided tunable properties, controlled deposition, and stable feature formation, enabling simple, low-cost, rapid, and robust fabrication of high-resolution hydrophobic barriers. Using this approach, we demonstrated improved fluid confinement and pattern fidelity on paper substrates, fabricated high-resolution paper microfluidic devices down to 150 m channel width, and enhanced the sensitivity of an LFA for a malaria diagnostic test. These results highlight the potential of this silicone ink platform as a practical and scalable strategy for advancing high-performance paper-based diagnostic technologies.