An ICT-based fluorescence enhancement probe for detection of Sn²⁺ in cancer cells

Development of a novel fluorescence enhancement probe for detection of Sn²⁺ in organisms, with high selectivity and sensitivity, is of great interest but remains a great challenge. Herein, an ICT-based fluorescence probe TPPB was rationally developed to act as an 'enhancement' luminescent and "naked-eye" indicator for Sn²⁺ detection. Importantly, spectroscopic studies indicated that TPPB was a fluorescence enhancement sensor for Sn²⁺ with rapid response, low detection limit (0.116 μM) and excellent binding constant (1.6 × 10⁴ M^-1). The mechanism of TPPB response to Sn²⁺ was further proved by ¹H NMR titration, and enhancement calculations. Furthermore, TPPB is applied as a fluorescence probe for imaging in Hela cells, indicated that it can be potentially applied for Sn²⁺ sensing in biological fields.