In this paper, a sensing probe (denoted as CFE) for tumor-biomarker 5-hydroxyindoleacetic acid (5-HIAA) was firstly synthesized. Its sensing mechanism was confirmed as the recovery of fluorescein structure via an ester-exchange reaction, accompanied with emission turn on effect towards 5-HIAA. To improve photostability and minimize self-quenching/aggregation of CFE molecules, they were loaded into silica based MCM-41 spheres and UCNPs-cored (up-conversion nanoparticles) MCM-41 spheres. Corresponding composite samples, denoted as CFE@MCM-41 and CFE@MCM-41@UCNPs, were carefully discussed to confirm their structure, including XRD, N₂ adsorption and desorption, SEM/TEM and TGA. The energy transfer from secondary excitation source UCNPs to probe CFE was confirmed by Forester radius calculation and emission lifetime comparison. Sensing performance of CFE@MCM-41 and CFE@MCM-41@UCNPs were finally discussed in detail. They showed emission turn on effect towards 5-HIAA with good selectivity. CFE@MCM-41 showed linear response, while CFE@MCM-41@UCNPs showed exponential response, resulting in a warning signal when analyte concentration was higher than a critical level. The reason for this exponential response was discussed and explained. Their practical sensing result for human urine test was compared to HLPC method and literature methods, which confirmed the promising result of CFE@MCM-41 and CFE@MCM-41@UCNPs.

本文首先合成了一种肿瘤生物标记物5-羟基吲哚乙酸（5-HIAA）的传感探针（称为CFE）。通过酯交换反应恢复荧光素结构，并伴随着向5-HIAA的发射开启效应，证实了其传感机制。为了提高光稳定性并最大程度地减少CFE分子的自猝灭/聚集，将它们装入基于二氧化硅的MCM-41球和以UCNPs为核心（上转换的纳米颗粒）MCM-41球。仔细讨论了相应的复合样品，分别表示为CFE @ MCM-41和CFE @ MCM-41 @ UCNPs，以确认其结构，包括XRD，N ₂吸附和解吸，SEM / TEM和TGA。通过福雷斯特半径计算和发射寿命比较，证实了从次级激发源UCNPs到探针CFE的能量转移。最后详细讨论了CFE @ MCM-41和CFE @ MCM-41 @ UCNP的传感性能。他们显示出对5-HIAA具有良好的选择性的发射开启效应。CFE @ MCM-41显示线性响应，而CFE @ MCM-41 @ UCNPs显示指数响应，当分析物浓度高于临界水平时会发出警告信号。讨论并解释了此指数响应的原因。将其在人体尿液测试中的实际感测结果与HLPC方法和文献方法进行了比较，证实了CFE @ MCM-41和CFE @ MCM-41 @ UCNPs的前景良好。