Perylene diimide functionalized nano-silica: green emissive material for selective probing and remediation of 4-nitrocatechol, Ru3+, and Cu2+ with biosensing applications†

Hybrid materials having dual applications in environmental monitoring and remediation are vital for mitigating pollution and economic benefits. In this regard, mesoporous silica is extensively studied compared to nano-silica materials due to challenges in controlling particle size morphology, and aggregation. In this work, a hybrid material was developed using nano-silica as a substrate and perylene diimide derivative as a fluorophore for simultaneous detection and adsorption of specific toxic analytes. A microemulsion method was applied for the synthesis of nano-silica with spherical to discoid morphology providing a high surface area. The surface immobilization of perylene diimide and subsequent bay-functionalization yielded the green emissive material nano-SiO₂@BAPERTOL. This material selectively detects 4-nitrocatechol (4-NC) via dynamic fluorescence quenching (FRET), and Ru³⁺ and Cu²⁺ among metal cations through static fluorescence quenching, with LODs of 4.34 nM, 0.56 nM, and 0.43 nM, respectively. This material exhibits hydrogen bonding-mediated high adsorption capacity (∼775 mg g⁻¹) towards 4-NC and coordination-driven adsorption of Ru³⁺ and Cu²⁺ ions (460, 566 mg g⁻¹). Also, the biosensing potential of the material was evaluated using brine shrimp (Artemia nauplii). Conclusively, the material serves as a single recyclable platform for selective detection and remediation of 4-NC, Ru³⁺, and Cu²⁺ ions, demonstrating superior performance and sustainability.