Encapsulation of DASP （4-[4-（dimethylamino）styryl]-l-octylpyridinium bromide） with amylose, and conformational transitions of amylose upon complexation with the dyes were investigated using UV-vis, fluorescence an...Encapsulation of DASP （4-[4-（dimethylamino）styryl]-l-octylpyridinium bromide） with amylose, and conformational transitions of amylose upon complexation with the dyes were investigated using UV-vis, fluorescence and two-photon absorption properties in various Dimethyl Sulfoxide （ DMSO）/H20 mixtures. Encapsulation of the dye was achieved by dilution of DMSO stock solutions of the chromophores （1 x 10^-3 M） and amylose （1 x 10^-1 M） with DMSO, followed by a dropwise addition of H20 with continuous stirring at room temperature. At less than 40% aqueous DMSO solutions, the chromophores had a stable encapsulation with amylose and showed over 100 times the fluorescence intensity of non-encapsulated chromophores. Both of the dye solution with and without amylose also exhibit 2PA （two-photon absorption）, as determined by nonlinear absorption measurements using 10 ns laser pulses at 800 nm. The respective values of two-photon cross-sections are 13.3 x 10.20 for encapsulated dye solution and 2.53 x 10.20 cma/GW for non encapsulated dye solution. The data clearly indicate that the contribution of the encapsulated dye dominates the two-photon absorption cross-section of the non encapsulated dye at 800 nm.展开更多
文摘Encapsulation of DASP （4-[4-（dimethylamino）styryl]-l-octylpyridinium bromide） with amylose, and conformational transitions of amylose upon complexation with the dyes were investigated using UV-vis, fluorescence and two-photon absorption properties in various Dimethyl Sulfoxide （ DMSO）/H20 mixtures. Encapsulation of the dye was achieved by dilution of DMSO stock solutions of the chromophores （1 x 10^-3 M） and amylose （1 x 10^-1 M） with DMSO, followed by a dropwise addition of H20 with continuous stirring at room temperature. At less than 40% aqueous DMSO solutions, the chromophores had a stable encapsulation with amylose and showed over 100 times the fluorescence intensity of non-encapsulated chromophores. Both of the dye solution with and without amylose also exhibit 2PA （two-photon absorption）, as determined by nonlinear absorption measurements using 10 ns laser pulses at 800 nm. The respective values of two-photon cross-sections are 13.3 x 10.20 for encapsulated dye solution and 2.53 x 10.20 cma/GW for non encapsulated dye solution. The data clearly indicate that the contribution of the encapsulated dye dominates the two-photon absorption cross-section of the non encapsulated dye at 800 nm.
