Coordination coupling enhanced two-photon absorption of a ZnS-based microhybrid for two-photon microscopy imaging in HepG2.

Coordination coupling induced self-assembly of ZnS microparticles was performed with the help of a π-conjugated sulphur-terminal Zn(ii) complex ZnS2L (L = N-hexyl-3-{2-[4-2,2':6',2''-terpyridin-4'-yl-phenyl]ethenyl}-carbazole). The interactions between ZnS and ZnS2L components at the interface, which were analyzed by far-IR and XPS, resulted in a tunable single-photon excited fluorescence and an enhanced nonlinear optical response, including a two-photon absorption cross section and a two-photon excited fluorescence. Such an enhancement in nonlinear optical properties was triggered by the coordination coupling effect between terminal S atoms of ZnS2L and naked Zn2+ ions at the surface of ZnS particles. Thus, the novel hybrid system displayed a unique two-photon excited fluorescence to facilitate promising two-photon microscopy imaging of HepG2 cells upon NIR light illumination at 840 nm. The hybrid shows a stronger ability to enter the cells than free ZnS2L.

Structural elucidation of three antioxidative polysaccharides from Tricholoma lobayense.

Tricholoma lobayense is a nutritious mushroom with great health benefits. Three polysaccharides with purity higher than 99% were successfully extracted from Tricholoma lobayense. The molecular weights of TLH-1, TLH-2 and TLH-3 were determined to be 8.43×105，5.36×105 and 4.53×103Da, respectively. The backbones of TLH-1 and TLH-2 were mainly composed of 1,4-linked α-d-glucopyranosyl. However, polysaccharide TLH-3 was found to be a highly branched glucogalactan, which is made up of 1,3-linked α-d-glucopyranosyl branched at C-6 and 1,3-linked ß-d-galactopyranosyl. In vitro antioxidant activity assays revealed that TLH-3 exhibited highest antioxidant activities among the polysaccharides from Tricholoma lobayense, which were comparable to those of ascorbic acid. The results suggested that the outstanding antioxidant activities of TLH-3 might depend on its low molecular weight, high branch degree, versatile linkage types and complex conformation. These characteristics make TLH-3 an attractive natural antioxidant for food and pharmaceutical applications.

Efficient two-photon-sensitized luminescence of a novel europium(III) ß-diketonate complex and application in biological imaging.

A novel europium(III) ß-diketonate complex exhibiting bright two-photon-sensitized luminescence is synthesized and applied as a two-photon-sensitized luminescent probe to stain DNA in live cells.