Photoelectrochemistry with Ordered CdS Nanoparticle/Relay or Photosensitizer/Relay Dyads on DNA Scaffolds

Abstract

A change of direction: The intensity and direction of photocurrents in photosensitizer–electron acceptor dyads anchored to electrodes is controlled by the orientation and composition of the subunits. DNA templates attached to electrode surfaces act as scaffolds for the assembly of the dyads, which comprise either CdS nanoparticles or ruthenium(II) polypyridyl complexes in conjunction with viologen units that act as relays (see picture).

Photoelectrochemical sensing of glucose based on quantum dot and enzyme nanocomposites

“…The unique electrical and optical properties of semiconductor quantum dots (QDs) have been widely used in a range of optoelectronic applications, e.g., light-emitting diodes (LEDs) [1][2][3], solar cells [4,5], lasers [6][7][8][9], and sensor and biosensors system [10][11][12][13][14][15][16][17][18][19][20][21][22]. In biosensor system, the luminescent properties of semiconductor QDs are mostly studied and used in fluorescence applications.…”

Nucleotides and Nucleic Acids; Oligo- and Polynucleotides

“…Gold is also widely used as an electrode, and there are many applications for the detection of changes to oligonucleotides attached to them. Oligonucleotides attached to gold electrodes have been used to detect duplex melting, 471 hybridisation, 472,473 as an electrical relay in conjunction with an oligonucleotide-conjugated quantum dot, 474 for the detection of 5-methylcytosine following oxidation by anthraquinone, 475 as a method for the detection and amplification of telomerase 476 and, in conjunction with an enzyme assay, a sensitive (femtomolar) method for detecting target DNA. 477 Gold-functionalised nanoparticles are more widely used, and are useful as they undergo a colour change from red to purple on aggregation, as well as possessing surface plasmon properties.…”

“…The oligonucleotides are attached to a gold electrode and are arranged such that they can present the components of the relay system, being quantum dots and a photosensitiser. 474 Quantum dots have been used to monitor the interactions with single-walled carbon nanotubes, where it forms a helical structure independent of the DNA sequence or length. 595 Quantum dots have been incorporated into two-dimensional tile self-assemblies of oligonucleotides, providing a fluorescent handle for monitoring and detection.…”

Enhanced Hydrogen Production from DNA‐Assembled Z‐Scheme TiO2–CdS Photocatalyst Systems

“…[5,[17][18][19][20][21][22] Fore xample,T ada et al developed an anisotropic CdS/Au/TiO 2 system in which all the components were spatially fixed with Au facilitating electron transfer. Finally,s ince electron transfer largely depends on diffusion, simply mixing electron mediators with different catalysts in solution requires ah igh concentration of redox molecules to avoid rate limitations but which can lead to undesired side oxidation/reduction reactions.T oaddress these challenges,weutilize DNAinthis work as as tructure-directing agent [23][24][25][26][27][28][29][30][31][32][33][34][35][36] to spatially organize well-defined TiO 2 and Pt decorated CdS (Pt@CdS) nanocrystals.Byusing DNAasanassembler,asignificant increase in H 2 production was observed upon photoillumination compared to Pt@CdS or TiO 2 alone directly in solution. [21] In almost all of these cases,o ptimal catalysis is typically obtained by interfacing different materials through aggregation (for example,e lectrostatic interactions [1] )o re pitaxial nucleation of one material on top of another.…”