ScholarWorks@성균관대학교

초록

Ensuring food quality and safety is crucial, as the consumption of contaminated or substandard food poses serious risks to public health and imposes a substantial economic burden. Among various food safety concerns, milk adulteration with urea has emerged as a significant issue. This study presents a highly sensitive dual-mode colorimetric and fluorometric urea sensor for milk adulteration detection, utilizing enzymatic hydrolysis with Fenton-mediated plasmonic etching. The urease-catalyzed hydrolysis of urea produces ammonia, which inhibits the Fenton reaction, thereby modulating the localized surface plasmon resonance (LSPR) of gold nanobipyramids (AuNBPs). The resulting LSPR shift (Delta lambda > 150 nm) generates a distinct colorimetric response across a broad urea concentration range (0-5 mM), with a low limit of detection (LoD) of 0.09 mu M. Moreover, the tunable LSPR of AuNBPs serves as a dynamic quencher for upconversion nanoparticles (UCNPs) via F & ouml;rster resonance energy transfer (FRET), enabling ratiometric fluorometric sensing with high sensitivity (LoD of 0.056 mu M). The spectral overlap between the LSPR of AuNBPs and the green/red emission of UCNPs facilitates a dynamic "Off/On-On/Off" response, ensuring accurate urea quantification in fluorescence mode. Furthermore, a smartphone-based RGB analysis enhances accessibility for on-site monitoring of urea levels, making this sensor a promising tool for real-world applications.

키워드