Visual Detection Strategy Based on Size-Gradient Coffee Rings on a Superslippery Platform

• DOI: 10.1021/acsami.4c22774
• Publication Date: 2025-03-11T15:23:18Z
• Authors: Yuyan Li; Kunming Xing; Yumin Liu; Kexin Liu; Guangyao Tan; Yingnan Sun; Shusheng Zhang

Superwetting surfaces have attracted considerable attention in analytical fields due to their unique ability concentrate target analytes within evaporating droplets, characterized by a constant contact angle and centripetal mobile line. While previous studies underscored the resistance of superslippery coffee-ring effect, our research presents novel strategy that dynamically introduces effect on such for visual detection. By harnessing synergistic interaction between line properties surface, work leverages affinity recognition functionalized surface analyte droplet create defects pinning, thereby generating coffee rings enabling qualitative detection based distinct patterns. Moreover, we establish linear relationship where coffee-ring's diameter decreased with increasing initial concentration, facilitating quantitative As proof concept, demonstrate naked-eye capability using streptavidin dilutions ranging from 10–7 10–11 M Escherichia coli concentrations 108 104 CFU/mL, visualized suspended micro-/nanoparticles. To best knowledge, it is first time utilized pinning ring formation, both This offers user-friendly easily interpretable method, making particularly advantageous point-of-care testing.