Because of its broad antibacterial range, the fluoroquinolone antibiotic ciprofloxacin (CIP) has been used extensively to treat bacterial infections in humans. However, it has been demonstrated that the excessive use of CIP will endanger human health and destroy the ecological environment. Therefore, rapid, facile and accurate detection of CIP is essential for real-world applications. In this study, a novel surface-enhanced Raman scattering (SERS) sensor with self-cleaning ability was synthesized and successfully employed for ultra-sensitive and specific detection of CIP. Specifically, ZnFe₂O₄@SiO₂-Au (ZSAu) nanocomposites (NCs) with different Au nanocrystals gap were developed. The relationship between various Au nanocrystals gap and SERS performance was investigated using finite-difference time-domain (FDTD) method. The solid-state Raman scattering spectrum of CIP molecule was also optimized and calculated using the density functional theory (DFT) method. After modifying with molecularly imprinted polymers (MIPs), ZSAu-MIPs NCs achieved specific detection of CIP in water environments, with the detection limit of low as 10^-9 M for CIP. A strong linear correlation between SERS intensity and the logarithm of CIP concentration suggested that ZSAu-MIPs NCs could be applied for quantitative detection of CIP at uncertain concentrations. In addition, ZSAu-MIPs NCs with self-cleaning ability could be recycled and reused with the assistance of magnet. After six cycles, ZSAu-MIPs NCs still exhibited good SERS performance. This magnetic MIPs-based SERS sensor offers a promising and recyclable method for ultra-sensitive detection of CIP in complex water environments.

中文翻译：

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环保型自清洁磁性 MIPs-SERS 传感器，用于在复杂水环境中超灵敏地检测环丙沙星


由于其广泛的抗菌范围，氟喹诺酮类抗生素环丙沙星 （CIP） 已被广泛用于治疗人类细菌感染。然而，事实证明，过度使用 CIP 会危害人类健康并破坏生态环境。因此，快速、简单和准确地检测 CIP 对于实际应用至关重要。本研究合成了一种具有自清洁能力的新型表面增强拉曼散射 （SERS） 传感器，并成功用于 CIP 的超灵敏和特异性检测。具体来说，开发了具有不同 Au 纳米晶间隙的 ZnFe₂O₄@SiO_2-Au （ZSAu） 纳米复合材料 （NCs）。使用有限差分时域 （FDTD） 方法研究了各种 Au 纳米晶间隙与 SERS 性能之间的关系。CIP 分子的固态拉曼散射光谱也使用密度泛函理论 （DFT） 方法进行了优化和计算。用分子印迹聚合物 （MIP） 修饰后，ZSAu-MIPs NCs 实现了对水环境中 CIP 的特异性检测，CIP 的检出限低至 ^10-9 M。SERS 强度与 CIP 浓度对数之间的强线性相关性表明，ZSAu-MIPs NC 可用于定量检测不确定浓度的 CIP。此外，具有自清洁能力的 ZSAu-MIPs NCs 可以在磁铁的帮助下进行回收和再利用。6 个循环后，ZSAu-MIPs NCs 仍然表现出良好的 SERS 性能。这种基于 MIPs 的磁性 SERS 传感器为复杂水环境中的 CIP 超灵敏检测提供了一种有前途且可回收的方法。