Abstract：
Fluorescent microspheres are of significant interests due to their wide applications in biotechnology fields. However, their preparation presents several challenges, such as the need for dye labeling, the complexity of materials and often sophisticated preparation conditions. Here a simple process for hydrophilic and crosslinked polyurethane (CPU) microspheres, with carboxyl groups on the surface via one-step precipitation polymerization in 40 min, is presented. The microsphere size is easily adjusted by varying experimental conditions. CPU microspheres exhibit high thermal and pH stability with good redispersibility in water, and emit fluorescence without any modification or dye labeling. The emission mechanism is discussed. CPU microspheres are used as fluorescent probe to detect 4-nitrophenol (4-NP) based on their emission in UV light region, with excellent selectivity and sensitivity. In addition, they are reusable with detection limit unchanged after 7 cycles of reuses, a significant feature of this work. The mechanism of fluorescence detection is thoroughly explored and ascribed to the internal filtration effect. Based on the emission in visible light region, CPU microspheres are used as a model of PU microplastics (MPs) to visualize their biodistribution in HeLa and macrophage cells, as well as in zebrafish larvae, providing a reliable tracer for the visualization and tracking of PU MPs in organisms.
摘要：
荧光微球由于在生物技术领域的广泛应用而备受关注。然而,他们的准备带来了一些挑战，例如需要染料标记，材料的复杂性和通常复杂的制备条件。这里是一个简单的亲水和交联聚氨酯（CPU）微球的过程，通过一步沉淀聚合在40分钟内表面上的羧基，是presented。通过改变实验条件可以容易地调节微球尺寸。CPU微球具有高的热稳定性和pH稳定性，在水中具有良好的再分散性，并在没有任何修饰或染料标记的情况下发射荧光。讨论了发射机理。CPU微球被用作荧光探针，基于它们在紫外光区的发射来检测4-硝基苯酚(4-NP)，具有优异的选择性和灵敏度。此外,它们可以重复使用，经过7个循环的重复使用，检测限不变，这项工作的一个显著特点。彻底探索了荧光检测的机理，并将其归因于内部过滤效应。基于可见光区域的发射，CPU微球被用作PU微塑料（MPs）的模型，以可视化它们在HeLa和巨噬细胞中的生物分布，以及斑马鱼幼虫，为生物中PUMPs的可视化和跟踪提供可靠的示踪剂。
