Hafez Eslam, Elbalaawy Ahmed Y, Shaban Samy M, Yeom Jeonghee, Kim Min-Jae, Mostafa Mohamed H, Elmasry Mohamed R, Abualrejal Murad M A, Kim Dong-Hwan
School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea.
Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea.
ACS Sens. 2025 Jul 25;10(7):5256-5265. doi: 10.1021/acssensors.5c01527. Epub 2025 Jun 24.
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 (Δλ > 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 μM. Moreover, the tunable LSPR of AuNBPs serves as a dynamic quencher for upconversion nanoparticles (UCNPs) via Förster resonance energy transfer (FRET), enabling ratiometric fluorometric sensing with high sensitivity (LoD of 0.056 μM). 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.
确保食品质量和安全至关重要，因为食用受污染或不合格的食品会对公众健康构成严重风险，并带来巨大的经济负担。在各种食品安全问题中，牛奶掺假尿素已成为一个重大问题。本研究提出了一种用于牛奶掺假检测的高灵敏度双模式比色和荧光尿素传感器，利用酶促水解与芬顿介导的等离子体蚀刻技术。尿素酶催化尿素水解产生氨，氨抑制芬顿反应，从而调节金纳米双棱锥（AuNBPs）的局域表面等离子体共振（LSPR）。由此产生的LSPR位移（Δλ>150nm）在较宽的尿素浓度范围（0-5mM）内产生明显的比色响应，检测限低至0.09μM。此外，AuNBPs的可调谐LSPR通过福斯特共振能量转移（FRET）作为上转换纳米颗粒（UCNPs）的动态猝灭剂，实现高灵敏度的比率荧光传感（检测限为0.056μM）。AuNBPs的LSPR与UCNPs的绿色/红色发射之间的光谱重叠促进了动态的“关/开-开/关”响应，确保了荧光模式下尿素的准确定量。此外，基于智能手机的RGB分析提高了现场监测尿素水平的可及性，使该传感器成为实际应用中有前景的工具。
