Bioinspired\nComposite Materials with Amplified Clusteroluminescence:\nChemodosimetric Interaction Targeting Hypochlorite in Aqueous Medium

Owing to the advantages\nof cellulose such as exceptional biocompatibility\nand biodegradability, we synthesized cellulose-grafted bisindolyl\nmethane (BIM) (<b>1. Cell</b>) composite. This biobased smart\nmaterial was used as an effective colorimetric and fluorescent sensor\nfor hypochlorite in the aqueous medium with a detection limit of 0.02\nμM. Interestingly, cellulose exhibited inherent clusteroluminescence\nin solution, which was further intensified by the probe acting as\na dopant. Both the boronic acid and bisindole groups in probe <b>1</b> are essential for this enhanced fluorescence, as boronic\nacid enables boronate ester formation with cellulose, while the bisindole\ngroups facilitate additional hydrogen bonding interactions. This unique\ndual functionality produces a strong, solution-phase clusteroluminescent\neffect, creating a rigid microenvironment that promotes long-range\nexciton migration and an amplified fluorescence response. Furthermore,\nthe <b>1. Cell</b> exhibited ∼2.8-fold quenching, while\nprobe <b>1</b> alone exhibited negligible fluorescence change\nin the presence of hypochlorite. Mechanistic investigation reveals\nthat the probe formed a boronate ester via the interaction with cellulose,\nwhich was subsequently cleaved in the presence of hypochlorite. The\ndifferences in the response might be attributed to the distinct nature\nof their self-assemblies; <b>1. Cell</b> could form long-range\nhighly ordered aggregates, while probe <b>1</b> alone in the\naqueous medium resulted in spontaneous random aggregates. Additionally,\nwe employed cellulose paper strips to explore the practicability of\nthe probe as a paper-based sensor. The chemically modified paper strips,\ngrafted with probe molecules, were found to be stable for a week and\ncould effectively detect hypochlorite in the presence of interfering\nanalytes via the naked eye and fluorescent color-changing response.