15 research outputs found
Molecular and Nano-engineering with iron, ruthenium and carbon: Hybrid structures for sensing
Metal complexes and 2D materials like graphene were combined to produce structures that can function as sensors. Using spin crossover materials, both in bulk single crystal form and in thin layer form, graphene-based electronic sensors were produced and characterized that can detect spin switches in the spin crossover materials. At the same time, the light-activatable ruthenium complexes were researched for their application in sensors that can monitor reactions that were triggered by light. We found that the photoreaction of a ruthenium complex with a nucleobase could be triggered in paper-based graphene devices. Moreover, we found that this ruthenium scaffold could also be used to increase the signal strength in a nanopore-based DNA detection system. Lastly, a ruthenium complex was designed that had a sensing function built in, as a dual-function molecule with a sensing and anticancer function. Overall, combining metal complexes with graphene was found to be a successful strategy to produce hybrid structures for sensing.Metals in Catalysis, Biomimetics & Inorganic Material
Highly ordered, self-assembled monolayers of a spin-crossover complex with in-plane interactions
For the technological integration of molecular switches in electronic devices, self-assembling nanomaterials of such switches are highly sought after. The syntheses of a new tetrapyridyl ligand bearing a C12 alkyl chain and two N-H bridges (compound 1) and of its iron(II) complex [Fe(1)(NCS)(2)] (compound 2), are described. Magnetic susceptibility data for bulk samples of 2 confirmed their gradual spin-crossover properties. The self-assembly of 1 and 2 on highly ordered pyrolytic graphite surfaces (HOPG) was investigated by Scanning Tunneling Microscopy (STM). Both compounds 1 and 2 formed ordered monolayers after deposition by drop casting. The patterns of the two compounds are very different, which is attributed to the fundamentally different hydrogen bonding networks before and after coordination of Fe(NCS)(2) to the tetradentate chelate. Two possible models for the self-assembly of 1 and 2 are provided. This work suggests that it is possible to design molecular switches that self-assemble on surfaces in highly ordered monolayer films. This is a significant step in the development of spin-switching materials, which may streamline the integration of molecular switches in for example memory and sensing devices.Quantum Matter and Optic
Sensing at the Surface of Graphene Field-Effect Transistors
Recent research trends now offer new opportunities for developing the next generations of labelâfree biochemical sensors using graphene and other twoâdimensional materials. While the physics of graphene transistors operated in electrolyte is well grounded, important chemical challenges still remain to be addressed, namely the impact of the chemical functionalizations of graphene on the key electrical parameters and the sensing performances. In fact, graphene â at least ideal graphene â is highly chemically inert. The functionalizations and chemical alterations of the graphene surface â both covalently and nonâcovalently â are crucial steps that define the sensitivity of graphene. The presence, reactivity, adsorption of gas and ions, proteins, DNA, cells and tissues on graphene have been successfully monitored with graphene. This review aims to unify most of the work done so far on biochemical sensing at the surface of a (chemically functionalized) graphene fieldâeffect transistor and the challenges that lie ahead. The authors are convinced that graphene biochemical sensors hold great promise to meet the everâincreasing demand for sensitivity, especially looking at the recent progresses suggesting that the obstacle of Debye screening can be overcome.Supramolecular & Biomaterials Chemistr
Sensing at the surface of graphene field-effect transistors
Supramolecular & Biomaterials Chemistr
A Lock-and-Kill anticancer photoactivated chemotherapy agent: this article is part of a Special Issue celebrating the 50thAnniversary of the American Society for Photobiology
Photosubstitutionally active ruthenium complexes show high potential as prodrugs for the photoactivated chemotherapy (PACT) treatment of tumors. One of the problems in PACT is that the localization of the ruthenium compound is hard to trace. Here, a ruthenium PACT prodrug, [Ru(3)(biq)(STF-31)](PF6 )2 (where 3 = 3-(([2,2':6',2âł-ter- pyridin]-4'-yloxy)propyl-4-(pyren-1-yl)butanoate) and biq = 2,2'-biquinoline), has been prepared, in which a pyrene tracker is attached via an ester bond. The proximity between the fluorophore and the ruthenium center leads to fluorescence quenching. Upon intracellular hydrolysis of the ester linkage, however, the fluorescence of the pyrene moiety is recovered, thus demonstrating prodrug cellular uptake. Further light irradiation of this molecule liberates by photosubstitution STF-31, a known cytotoxic nicotinamide phosphoribosyltransferase (NAMPT) inhibitor, as well as singlet oxygen via excitation of the free pyrene chromophore. The dark and light cytotoxicity of the prodrug, embedded in liposomes, as well as the appearance of blue emission upon uptake, were evaluated in A375 human skin melanoma cells. The cytotoxicity of the liposome-embedded prodrug was indeed increased by light irradiation. This work realizes an in vitro proof-of-concept of the lock-and-kill principle, which may ultimately be used to design strategies aimed at knowing where and when light irradiation should be realized in vivo.Seventh Framework Programme (FP7)335879Metals in Catalysis, Biomimetics & Inorganic MaterialsSupramolecular & Biomaterials Chemistr
Molecular and Nano-engineering with iron, ruthenium and carbon: Hybrid structures for sensing
Metal complexes and 2D materials like graphene were combined to produce structures that can function as sensors. Using spin crossover materials, both in bulk single crystal form and in thin layer form, graphene-based electronic sensors were produced and characterized that can detect spin switches in the spin crossover materials. At the same time, the light-activatable ruthenium complexes were researched for their application in sensors that can monitor reactions that were triggered by light. We found that the photoreaction of a ruthenium complex with a nucleobase could be triggered in paper-based graphene devices. Moreover, we found that this ruthenium scaffold could also be used to increase the signal strength in a nanopore-based DNA detection system. Lastly, a ruthenium complex was designed that had a sensing function built in, as a dual-function molecule with a sensing and anticancer function. Overall, combining metal complexes with graphene was found to be a successful strategy to produce hybrid structures for sensing.</table
Highly ordered, SelfâAssembled Monolayers of a SpinâCrossover Complex with InâPlane Interactions
For the technological integration of molecular switches in electronic devices, self-assembling nanomaterials of such switches are highly sought after. The syntheses of a new tetrapyridyl ligand bearing a C12 alkyl chain and two N-H bridges (compound 1) and of its iron(II) complex [Fe(1)(NCS)(2)] (compound 2), are described. Magnetic susceptibility data for bulk samples of 2 confirmed their gradual spin-crossover properties. The self-assembly of 1 and 2 on highly ordered pyrolytic graphite surfaces (HOPG) was investigated by Scanning Tunneling Microscopy (STM). Both compounds 1 and 2 formed ordered monolayers after deposition by drop casting. The patterns of the two compounds are very different, which is attributed to the fundamentally different hydrogen bonding networks before and after coordination of Fe(NCS)(2) to the tetradentate chelate. Two possible models for the self-assembly of 1 and 2 are provided. This work suggests that it is possible to design molecular switches that self-assemble on surfaces in highly ordered monolayer films. This is a significant step in the development of spin-switching materials, which may streamline the integration of molecular switches in for example memory and sensing devices.Quantum Matter and Optic
Genetically determined prospect to become long-lived is associated with less abdominal fat and in particular less abdominal visceral fat in men
Pathophysiology, epidemiology and therapy of agein