Bifunctional linkers for modification of TiO 2 nanoparticles were prepared containing a catechol group for TiO 2 surface attachment and a maleimide and alkyne group for Michael addition and Cu catalysed Huisgen cycloaddition respectively. Peptide and fluorophore functionalised TiO 2 NPs were prepared, different purification methodologies were explored and conjugates were characterized using a range of methods.
Using a simple bifunctional bridging linker, nanosized gold and titanium dioxide composites are prepared containing different Au loadings. Linker is synthesized to contain both catechol and thiol moieties to enable binding to the TiO2 and Au surface respectively. Au/TiO2 nanocomposites are prepared using simple synthetic route that allows the control over the amount of Au nanoparticles, a property which plays a significant role in the catalytic activity of hybrid materials. Photocatalytic activity of materials prepared using different TiO2 precursors is investigated using reactive oxygen species sensitive assay based on activation of horseradish peroxidase (HRP) enzyme. Significant increase in catalytic activity is observed for all Au/TiO2 nanocomposites with Au/TiO2 prepared by use of the bridging linker being up to 5.5 times more active than bare commercial TiO2 nanoparticles. In addition to 365 nm light excitation, less energetic 470 nm light, which is more suitable for the use with biological systems, is used to induce photocatalytic activity. Finally, prepared photocatalytic materials are successfully used to exert temporal control over enzymatic activity, a feature which is important for the study of both enzymatic activity and design of novel bio‐sensing platforms.
We present the study of reactive oxygen species production under the light irradiation of two different types of TiO2nanocrystals. Both TiO2spheric NPs and anisotropic nanorods were investigated using activation of the horseradish peroxidase enzyme and subsequent substrate oxidation into a fluorescent product. The influence of the surface ligand dopamine was also explored to shed more light on the effect of catechol binders on the photoactivity of TiO2species.
On page 907, a gold‐titanium dioxide (Au/TiO2) hybrid prepared by L. Fruk and co‐workers using a bifunctional bridging linker is shown on this cover image. The bright yellow spots are gold nanoparticles stabilized by a dopamine‐lipoic acid derivative, which are then bound to titanium dioxide matrix (purple). This hybrid material shows remarkable catalytical activity towards activation of heme containing enzyme upon light irradiation.
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