There is an increasing need to develop simple yet effective sensors with high sensitivity, high selectivity, rapid response, and low cost for on-site detection of UO₂²⁺ in the environment in planned or emergency situations. Herein, we develop a UO₂²⁺ responsive interpenetrating porous photonic crystal ball (IPPCB) sensor by template replication and a two-step activation method. The amidoxime group and carboxyl group in the hydrogel drive the shrinkage of the hydrogel network through the coordination with UO₂²⁺, which reduces the lattice spacing, thereby changing the structure color and shifting the reflection peak position. Therefore, we can perform a semi-quantitative analysis of UO₂²⁺ with the naked eye or a fiber spectrometer. Benefiting from the sensor's spherical symmetry and periodic interpenetrating porous structure, the sensor can provide angle-independent, fast (12 min), and sensitive (minimum detection concentration of 1 nM) detection of UO₂²⁺. Moreover, IPPCBs have high selectivity and excellent regeneration performance, which can be applied to real sample detection.

中文翻译：

---

用于快速肉眼检测铀酰离子的互穿多孔光子晶体球

越来越需要开发具有高灵敏度、高选择性、快速响应和低成本的简单而有效的传感器，用于在计划或紧急情况下对环境中的 UO ₂ ^{2+进行现场检测。}在此，我们通过模板复制和两步激活方法开发了一种 UO ₂ ^{2+响应式互穿多孔光子晶体球 (IPPCB) 传感器。}_{水凝胶中的偕胺肟基团和羧基通过与UO 2} ²⁺的配位驱动水凝胶网络的收缩，使晶格间距减小，从而改变结构颜色和移动反射峰位置。_{因此，我们可以对 UO 2} ²⁺进行半定量分析用肉眼或光纤光谱仪。得益于传感器的球对称性和周期性互穿多孔结构，该传感器可以提供与角度无关、快速（12 分钟）和灵敏（最小检测浓度为 1 nM）的 UO ₂ ²⁺检测。此外，IPPCB具有高选择性和优异的再生性能，可应用于实际样品检测。