The efficient conversion of light energy into chemical energy is key for sustainable human development. Several photocatalytic systems based on photovoltaic electrolysis have been used to produce hydrogen via water reduction. However, in such devices, light harvesting and proton reduction are carried separately, showing quantum efficiency of about 10–12%. Here, we report a nano-hybrid photocatalytic assembly that enables concomitant reductive hydrogen production and pollutant oxidation with solar-to-fuel efficiencies up to 20%. The modular architecture of this plasmonic material allows the fine-tuning of its photocatalytic properties by simple manipulation of a reduced number of basic components.
Herein 2,3-dialdehyde cellulose beads prepared from Cladophora green algae nanocellulose were sulfonated and characterized by FTIR, conductometric titration, elemental analysis, SEM, ζ-potential, nitrogen adsorption–desorption and laser diffraction, aiming for its application as a potential immunosorbent material. Porous beads were prepared at mild reaction conditions in water and were chemically modified by sulfonation and reduction. The obtained 15 µm sized sulfonated beads were found to be highly charged and to have a high surface area of ~ 100 m2 g−1 and pore sizes between 20 and 60 nm, adequate for usage as immunosorbents. After reduction of remaining aldehyde groups, the beads could be classified as non-cytotoxic in indirect toxicity studies with human dermal fibroblasts as a first screening of their biocompatibility. The observed properties make the sulfonated cellulose beads interesting for further development as matrix material in immunosorbent devices.
Sulfonated cellulose beads were prepared by oxidation of Cladophora nanocellulose to 2,3-dialdehyde cellulose followed by sulfonation using bisulfite. The physicochemical properties of the sulfonated beads, i.e., high surface area, high degree of oxidation, spherical shape, and the possibility of tailoring the porosity, make them interesting candidates for the development of immunosorbent platforms, including their application in extracorporeal blood treatments. A desired property for materials used in such applications is blood compatibility; therefore in the present work, we investigate the hemocompatibility of the sulfonated cellulose beads using an in vitro whole blood model. Complement system activation (C3a and sC5b-9 levels), coagulation activation (thrombin-antithrombin (TAT) levels) and hemolysis were evaluated after whole blood contact with the sulfonated beads and the results were compared with the values obtained with the unmodified Cladophora nanocellulose. Results showed that neither of the cellulosic materials presented hemolytic activity. A marked decrease in TAT levels was observed after blood contact with the sulfonated beads, compared with Cladophora nanocellulose. However, the chemical modification did not promote an improvement in Cladophora nanocellulose hemocompatibility in terms of complement system activation. Even though the sulfonated beads presented a significant reduction in pro-coagulant activity compared with the unmodified material, further modification strategies need to be investigated to control the complement activation by the cellulosic materials.
8 October 2014 in The Journal of Physical Chemistry C