Ag Nanoparticle Arrays for Highly Sensitive and Reliable Sulfide Detection

Early disease diagnosis hinges on the sensitive detection of signaling molecules. Among them, hydrogen sulfide (H₂S) plays an important role in cardiovascular and neurological signal transduction. On-chip immunoanalysis, particularly interface detection based on nanoarrays, offers a highly promising avenue for ultrasensitive analysis due to its confined reaction volume and precise signal localization. This study introduces a Ag nanoparticle (NP) array for the sensitive detection of sulfide. The array applies the exceptional sensitivity of Ag to sulfide, where Ag reacts with S^2- to form Ag₂S, leading to a decrease in scattering intensity. The inherent parallel nature of the array with hundreds of independent reactions significantly enhances measurement reliability. The developed Ag nanoarray sensor demonstrates a remarkable response toward hydrogen sulfide across a wide dynamic range spanning 7 orders of magnitude (10 fM to 10 nM). This approach for sulfide detection provides an advanced platform with significantly enhanced sensitivity for biological sensing. Moreover, it holds great potential for the ultrahigh sensitivity detection of a diverse range of other biosignaling molecules.