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Hydrogen sulfide (H 2 S) is a kind of gaseous signal molecule in many physiological processes. In order to detect H 2 S, a novel "turn on" fluorescent probe 6,12-dihydroxyperylene-1,7-dione (DPD) was designed and synthesized. The probe DPD is fluorescence silence, while the addition of H 2 S induces an obvious green fluorescence with an obvious color change from dark blue to yellow-green. The probe shows excellent selectivity, fast response (2.5 min) and linear curve (0–90 μM) in wide effective pH range (4–10). Competition experiments are also revealed in corresponding studies and the detection limit is 3.6 μM. The response mechanism is proved to be the reduction of the probe by H 2 S, which is confirmed by 1H NMR. Furthermore, through the fluorescence turn-on signal toward H 2 S in Hela cells, probe DPD was successfully applied to monitor H 2 S in living Hela cells. Unlabelled Image • A "turn-on" probe DPD for hydrogen sulfide was developed. • DPD shows highly selective and sensitive response to hydrogen sulfide. • DPD shows rapid response and high sensitivity toward hydrogen sulfide. • The response mechanism of the probe DPD with H 2 S was confirmed to be reduction of carbonyl groups to hydroxyl groups. • DPD can monitor the exogenous cysteine in solution and living cells. [ABSTRACT FROM AUTHOR]

Spermine is an important biomarker for cancer diagnosis and treatment since it is dysregulated and overexpressed in tumors. Herein, a supramolecular reporter pair PPDD@SC4AD is exploited by complexing amphiphilic sulfonatocalix[4]arene (SC4AD) with pyrido[1,2- a ]pyrido[1′,2′:3,4]imidazo-[2,1-c]-6,7-dihydropyrazinium dibromide (PPDD). The reporter pair can detect spermine in biological systems. By detecting and depleting spermine, it realizes spermine imaging and induces apoptosis of tumor cells. SC4AD exhibits a high binding affinity and a strong complexation-induced fluorescence quenching effect. When complexing with spermine overexpressed in tumor cells, SC4AD can significantly release the fluorescence of PPDD. Moreover, spermine is efficiently encapsulated by calixarene to deplete spermine and induce apoptosis of tumor cells. The amphiphilicity of SC4AD can drive the self-assembly of PPDD@SC4AD to guarantee an efficient enhanced permeability and retention effect in vivo. PPDD@SC4AD may inspire the development of new integrated approaches of diagnosis and treatment. [Display omitted] • A host-dye reporter pair PPDD@SC4AD was used for spermine imaging and induced apoptosis in tumor cells. • PPDD@SC4AD can release the fluorescence of PPDD when complexing with overexpressed spermine in tumor cells. • The amphiphilicity of SC4AD can drive the self-assembly of PPDD@SC4AD to ensure EPR effect in vivo. • PPDD@SC4AD may provide a new idea for the development of new integrated methods of diagnosis and treatment. [ABSTRACT FROM AUTHOR]