Interfacial amplifier: High-throughput visual protein detection via droplet dynamics.

Rapid, visual protein detection at ultralow cost remains a critical unmet need for scalable point-of-care testing. We introduce a high-throughput platform leveraging interfacial droplet dynamics on a slippery liquid-infused porous surface (SLIPS) to directly translate protein-specific adsorption into macroscopic behavior. Protein concentration and identity modulate the critical sliding angle of droplets via interfacial film formation, enabling pretreatment-free, instrument-free identification of clinically relevant targets like proteinuria within minutes. This approach achieves parallel analysis of 170 samples on a single A4-sized substrate (5 minutes, ∼$0.008 per sample), requiring only visual readout. By amplifying nanoscale interfacial interactions into intuitive visual outputs, our SLIPS-based technology establishes a scalable, user-friendly paradigm for decentralized diagnostics and continuous health monitoring across diverse settings.