Hyperbranched poly(ester ether)s as an amplified fluorescence sensor for selective and sensitive Fe3+ detection and bioimaging

Abstract

AbstractChromophore‐free fluorescent hyperbranched polymers have attracted widespread attention as fluorescent sensors. However, achieving highly selective and sensitive detection with such sensors remains a major challenge. Herein, two kinds of hyperbranched poly(ester ether) fluorescent sensors (HBPEE1 and HBPEE2) without conventional chromophores were synthesized to provide a simple and effective method for the selective and sensitive detection of Fe3+. Benefiting from the branched structure and the aggregation of numerous oxygen‐rich groups, both hyperbranched poly(ester ether)s emitted strong blue fluorescence in solution, and compared with HBPEE2, HBPEE1 had a higher absolute quantum yield of 14.3% due to its larger molecular weight and denser structure. HBPEE1 exhibited an amplified fluorescence quenching response and superior selectivity and sensitivity in the recognition of Fe3+ among various metal ions. The fluorescence intensity of HBPEE1 at 450 nm showed a good linearity with the Fe3+ concentration in the range of 5–450 μM with the detection limit of 0.04 μM. Multiple Fe3+ detections with high reversibility have been achieved using EDTA‐2Na, which further confirmed the detection mechanism. In addition, the HBPEE1 sensor possessed low toxicity and can be employed for Fe3+ imaging in living cells, making it a potential candidate for biological research and clinical diagnosis.