Abstract：
A ratio luminescence probe was developed for detecting Staphylococcus aureus (S. aureus) based on luminescence energy transfer (LET) using double-wavelength emission (550 nm and 812 nm) upconversion nanoparticles (UCNPs) as donor, gold nanoparticles (AuNPs) as acceptor and the aptamer for S. aureus as the specific recognition and link unit. The LET process could cause luminescence quenching because of the spectral overlap between the acceptor and the donor at 550 nm. In the presence of S. aureus, S. aureus selectively combined with the aptamer, and the AuNPs left the surface of UCNPs, which weakened the quenching effect and restored the luminescence of UCNPs. Based on this, the ratio detection was realized by monitoring the change of the luminescence signal of the probe at 550 nm and taking the luminescence signal at 812 nm as the reference signal. Crucially, the probe has a fast reaction speed, with a reaction time of 25 min, and the detection of S. aureus is realized in the concentration range of 5.0 × 103-3.0 × 105 CFU/ml, with the detection limit of 106 CFU/ml. Therefore, the ratio probe has great potential for detecting of S. aureus in food because of its high sensitivity, fast speed and good selectivity.
摘要：
开发了一种用于检测金黄色葡萄球菌的比例发光探针（S.金黄色葡萄球菌）基于使用双波长发射（550nm和812nm）上转换纳米颗粒（UCNPs）作为供体的发光能量转移（LET），金纳米粒子(AuNPs)作为受体,金黄色葡萄球菌的适体作为特异性识别和连接单元。由于受体和供体在550nm处的光谱重叠,LET过程可以引起发光猝灭。在金黄色葡萄球菌的存在下，金黄色葡萄球菌选择性地与适体结合，AuNPs离开了UCNPs的表面，削弱了UCNPs的猝灭效应，恢复了UCNPs的发光。基于此,通过监测探针在550nm处的发光信号的变化并以812nm处的发光信号作为参考信号来实现比值检测。至关重要的是，探针反应速度快，反应时间为25分钟，在5.0×103-3.0×105CFU/ml的浓度范围内实现了金黄色葡萄球菌的检测，检出限为106CFU/ml。因此,比例探针由于其高灵敏度,在食品中金黄色葡萄球菌的检测中具有巨大的潜力,速度快，选择性好。
