The detection of prostate specific antigen (PSA) is extremely important for the early diagnosis of prostate cancer. Herein, we report a dual-round signal amplification strategy for colorimetric/fluorescence/photoacoustic triple read-out detection of PSA using a silica coated Au@Ag core-shell nanorod (denoted Au@Ag@SiO2) based enzyme-linked immunosorbent assay (ELISA) system. In the presence of PSA, monoclonal primary antihuman PSA antibody (Ab1) captured PSA and was subsequently recognized by the secondary antihuman PSA detection antibody (Ab2) which was conjugated with glucose oxidase (GOx) functionalized magnetic beads (MBs) for signal amplification, then GOx catalyses the addition of glucose to generate hydrogen peroxide that etches the silver layer in Au@Ag@SiO2, thus producing abundant Ag+ to realize the second signal amplification. With the degradation of the silver layer, an obvious color change (green-to-pink) of the Au@Ag@SiO2 solution could be observed by the naked eye and its surface plasmon resonance (SPR) absorption had a red-shift, enhancing photoacoustic signal read-out at 780 nm. Additionally, the released Ag+ was caught by a Ag+-fluorescent probe (Ag+-FP) for enhanced fluorescence signal read-out. These results suggested that this ELISA system achieves a triple read-out detection of PSA. This work provides a promising strategy for multiple read-out detection of biomarkers, which has great potential in clinical diagnosis.

中文翻译：

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比色/光声/荧光三重读出检测前列腺特异性抗原的双轮信号放大策略。

前列腺特异性抗原（PSA）的检测对于前列腺癌的早期诊断极为重要。在此，我们报告了一种双轮信号放大策略，用于基于二氧化硅的Au @ Ag核壳纳米棒（表示为Au @ Ag @ SiO2）基于酶联免疫吸附测定的比色/荧光/光声三重检测PSA。 ELISA）系统。在存在PSA的情况下，单克隆抗人PSA一抗（Ab1）捕获了PSA，随后被抗人PSA二抗检测抗体（Ab2）识别，该抗体与葡萄糖氧化酶（GOx）功能化的磁珠（MBs）偶联以进行信号放大，然后GOx催化葡萄糖的添加，产生过氧化氢，该过氧化氢蚀刻Au @ Ag @ SiO2中的银层，从而产生丰富的Ag +，以实现第二次信号放大。随着银层的降解，肉眼可以观察到Au @ Ag @ SiO2溶液的明显颜色变化（从绿色变成粉红色），并且其表面等离子体共振（SPR）吸收具有红移，增强了在780 nm处读出光声信号。此外，释放的Ag +被Ag +荧光探针（Ag + -FP）捕获，从而增强了荧光信号的读取。这些结果表明，该ELISA系统可实现PSA的三重读出检测。这项工作为生物标志物的多读出检测提供了一种有希望的策略，在临床诊断中具有巨大的潜力。增强在780 nm处的光声信号读出。此外，释放的Ag +被Ag +荧光探针（Ag + -FP）捕获，从而增强了荧光信号的读取。这些结果表明，该ELISA系统可实现PSA的三重读出检测。这项工作为生物标志物的多读出检测提供了一种有前途的策略，在临床诊断中具有巨大的潜力。增强在780 nm处的光声信号读出。此外，释放的Ag +被Ag +荧光探针（Ag + -FP）捕获，从而增强了荧光信号的读取。这些结果表明，该ELISA系统可实现PSA的三重读出检测。这项工作为生物标志物的多读出检测提供了一种有希望的策略，在临床诊断中具有巨大的潜力。