Biosilicated CdSe/ZnS quantum dots as photoluminescent transducers for acetylcholinesterase-based biosensors.

CdSe/ZnS core/shell quantum dots (QDs) are functionalized with mercaptoundecanoic acid (MUA) and subsequently covered with poly-L-lysine (PLL) as the template for the formation of the silica outer shell. This nanocomposite is used as a transduction and stabilization system for optical biosensor development. The covalent immobilization of the enzyme acetylcholinesterase from Drosophila melanogaster (AChE) during the formation of the biomimetically synthesized silica is used here as a model, relatively unstable enzyme, as a proof of principle.

Biomimetically synthesized silica-carbon nanofiber architectures for the development of highly stable electrochemical biosensor systems.

Biomimetically synthesized silica and conductive activated carbon nanofibers (CNFs) are used in a synergistic manner for the development of a novel electrochemical biosensor system. Poly(L-lysine) templated silica grows and encapsulates the CNF-immobilized enzyme generating a highly stabilizing nanostructured environment for the underlying protein. Concurrently, CNFs provide both the required surface area for the high-capacity enzyme immobilization required in biosensors as well as direct electron transfer to the inner platinum transducer.

Novel methodology for the preparation of five-, seven-, and nine-membered fused rings on C60.

[reaction: see text] The photocycloaddition of dienyl cyclopropanes to C(60) gives a new synthetic approach to yield stereospecifically five-, seven-, and nine-membered [60]fullerene adducts. Our results suggest the formation of a biradical intermediate between the dienyl substrate and C(60). An electron transfer between the triplet excited state of C(60) and the dienyl substrate precedes the formation of the intermediate.

Reaction of an Aza[60]fullerene radical with diphenylmethanes and fluorenes: a mechanistic approach.

[reaction: see text] The mechanism of the reaction of azafullerene radical C(59)N(*) with diphenylmethane and 9-methyl-9H-fluorene has been investigated. The primary and secondary kinetic isotope effects provide strong evidence for a stepwise mechanism in which the hydrogen-atom abstraction is the rate-determining step.

Biradical intermediate in the [2 + 2] photocycloaddition of dienes and alkenes to [60]fullerene.

The photocycloaddition of vinylcyclopropanes to C60 yields stereospecifically a five-membered [60]fullerene adduct. These results suggest a biradical intermediate of the [2 + 2] photocycloaddition between dienes or arylalkenes and C60. An electron transfer between the triplet excited state of C60 and the unsaturated substrates precedes the formation of the intermediate.

Multicomponent redox gradients on photoactive electrode surfaces.

Redox gradients have been used to tailor the arrangement of photoactive ITO-electrodes at the molecular level.

Electrostatically arranged cytochrome c-fullerene photoelectrodes.

We have developed a molecular-level switch-a C(60)/cytochrome c modified ITO electrode-that reversibly transmits and processes solar energy.

Electrostatic complexation and photoinduced electron transfer between Zn-cytochrome c and [olyanionic fullerene dendrimers.

Two dendritic fullerene (DF) monoadducts, 2 and 3, which can carry up to 9 and 18 negative charges, respectively, were examined with respect to electrostatic complexation with Cytochrome c (Cytc). To facilitate comprehensive photophysical investigations, the zinc analogue of Cytc (ZnCytc) was prepared according to a novel, modified procedure. The association of ZnCytc and DF, and consequential photoinduced electron transfer within ZnCytc-DF from the photoexcited protein to the fullerene, was proven by fluorescence spectroscopy and transient absorption spectroscopy.