Novel fluorescence nanostructured materials obtained by entrapment of an ornamental bush extract in hybrid silica glass

Synthesis of some novel fluorescence nanomaterials loaded with photoactive polyphenols originated from plants with a high spectrum of biological activity, by replacing synthetic chemicals, may open new opportunities for optical and bio-medical applications. This paper presents the synthesis, characterization and fluorescence properties of a new class of materials based on host hybrid matrices obtained through templated sol–gel route, by hydrolysis and co-condensation of tetraorthoethylsilicate with octaisobutyltetracyclo [7.3.3.1 5,11 ] octasiloxane-endo-3,7-diol. The aim of paper is focused on the evaluation of the behavior of the fluorescence properties of ornamental bush extract at immobilization in a templated silica matrix and in a silica-silsesquioxane network, using as templates a neutral, non-toxic and biodegradable surfactant from poly(ethyleneglycol) class and a high biocompatible non-surfactant from glucidic class. The proofs of ornamental bush extract entrapment by physical interactions in silica based networks were provided by FT-IR and UV–VIS spectroscopy. The changes of polymer network due to the hydrogen bond interactions between residual Si–OH groups and functional groups of organic molecules from extract were evidenced by shifts of specific vibrations. In UV–VIS-NIR domain, the chromophore groups from ornamental bush extract were also evidenced by similar small shifts. As a result of ornamental bush extract entrapment, in all the immobilized samples the fluorescence intensity was more than 10 times amplified in samples templated with poly(ethylenglycol) surfactant) and of about 5 times in samples with glucidic template due to the physical adsorption of polyphenolic molecules from extract, excellent synergistic optical properties of SiO 2 and silsesquioxane compound and also due to a favorable conformational arrangement. The size of synthesized polymeric materials, estimated by dynamic light scattering technique showed main diameters less then 1.4 μm, namely 1,060 and 211 nm—for samples with d -glucose template and 1,330 and 531 nm—for samples with poly(ethyleneglycol) template, respectively, with a narrow size distribution and a polidispersity varying between 0.022 and 0.426. These results are in good accordance with TEM images that evidenced the presence of some polymeric aggregates which contain the vegetal extract immobilized inside hybrid SiO 2 -Sq polymeric network of about hundred nanometers size. This study bring new contributions