•Triazine–nickel(II) complexes was synthesized and characterized.•The mechanism of DNA binding and photoluminescence of the complexes were determined.•Complexes sensitively detect DNA over a wide concentration range.•Complex 1 can serve as optical probes for anaerobic nonaqueous solutions.We report here the synthesis of three new nickel(II) complexes: [Ni(PzTA)2CO3]·5H2O (PzTA = 2,4-diamino-6-(2′-pyrazin)-1,3,5-triazine) in 1, [NiQ(PyTA)(H2O)2]Cl·H2O (HQ = 8-hydroxyquinoline, PyTA = 2,4-diamino-6-(2′-pyridyl)-1,3,5-triazine) in 2, [NiQ(PzTA)(H2O)2]Cl·H2O in 3, and they were characterized by UV spectroscopy, elemental analysis, molar conductivity and X-ray single crystal diffraction. Binding of the complexes to ct-DNA was investigated with electronic spectroscopy, ethidium bromide displacement from DNA, viscometry and cyclic voltammetry. The results depicted the DNA binding mode of the three complexes was intercalation, and complex 1 together with external static-electricity. Moreover, the three complexes also presented potential anti-oxidant activity. Interestingly, we found 1 was sensitive to oxygen and to the polarity of nonaqueous solvents in fluorescence spectroscopy. Fluorescence of 2 and 3 is weak in neutral aqueous solvents, but is greatly enhanced by addition of ct-DNA. Thus, 2 and 3 can be used to DNA detection as DNA fluorescence probes with a LOD of 1.61 ng mL−1, 4.90 ng mL−1 for the relative wide linear range of 0.01–20 μg mL−1, 0.02–30 μg mL−1, respectively. These findings indicate that 1 may be a potential optical probe for oxygen-free environments in nonaqueous form, while 2 and 3 were DNA-targeted probes.Complex 2 and 3 can be used to DNA detection as DNA fluorescence probes with a LOD of 1.61 ng mL−1, 4.90 ng mL−1 for the relative wide linear range of 0.01–20 μg mL−1, 0.02–30 μg mL−1, respectively. These findings indicate 1 may be a potential optical probe for oxygen-free environments in nonaqueous form, while 2 and 3 were DNA-targeted probes.

•[Cu(pzta)2Cl]Cl·H2O was synthesized and characterized.•The mechanism of DNA binding and photoluminescence of the complex were determined.•The complex sensitively detects DNA over a wide concentration range.•The complex can serve as an optical probe for anaerobic nonaqueous solutions.We report here the synthesis of a new copper(II) complex of 2,4-diamino-6-(2′-pyrazin)-1,3,5-triazine [Cu(pzta)2Cl]Cl·H2O and its characterization using UV and IR spectroscopy, elemental analysis, and X-ray diffraction. Fluorescence spectroscopy revealed that the complex was sensitive to oxygen and to the polarity of nonaqueous solvents. Binding of the complex to DNA was investigated using UV spectroscopy, ethidium bromide displacement from DNA, cyclic voltammetry, and viscometry. The results revealed the DNA binding mode was intercalation together with external static-electricity. However, the complex can be also used to DNA detection as DNA fluorescence probe with a LOD of 4.21 ng mL−1 for the relative wide linear range between 0.2 and 17 μg mL−1. In conclusion, that synthetic method of the complex was easy with low expense and was relatively rapid and sensitive compared to most toxic fluorescence dyes. This finding would indicate the complex may be a potential DNA-targeted probes and optical probes for oxygen-free environments in nonaqueous form.Graphical abstractA new copper(II) complex, [Cu(pzta)2Cl]Cl⋅H2O has been synthesized and structurally characterized. The luminescence of the complex was investigated with fluorescence spectroscopy and it indicated that the complex was sensitive to oxygen molecules and the polarity of the solvent in nonaqueous solution.

•Incorporating microcapsules into starch film, a novel drug delivery system for pharmaceutical application was prepared.•With the development of synergistic interactions between these drug-carriers, the performances of the blend were improved significantly.•The blend film was found to be pH-sensitivity.•The blend films were possessed a pharmacodynamic efficacy after the incorporation.A novel drug delivery system, chitosan-microcapsules/starch blend film for antofloxacin controlled release, was prepared, and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (X-RD), thermogravimetry and derivative thermogravimetry (TG/DTG), and scanning electron microscopy (SEM). Following incorporation of the chitosan-microcapsules in the film matrix, the synergistic interactions between these drug-carriers were significant. The thermostability and mechanical properties of the blend film were greatly improved by the incorporation of the microcapsules. The water resistance of the blend film was enhanced by increasing the content of microcapsules, indicating that the microcapsules acted as moisture barriers. After being incorporated, chitosan-microcapsules/starch blend film shows a sustained drug release. The extent of the film degradation and microcapsules swelling in the release system indicated that the drug released of the blend film was pH-sensitive. The blend film exhibited pharmacodynamic efficacy because of the efficient drug releasing.