The interaction of double-stranded （ds） and G-quadruplex （G4） DNA with sulfonyl 5-fluorouracil derivatives （5-fluoro-l-（arylsulfonyl） pyrimidine-2,4 （1H,3H）-diones） was investigated in this research, in which Au electrodes modified with ds-DNA or G4-DNAs were used as a working electrode. The investigation showed that the binding affinity with G4-DNA was significantly increased when 5-fluorouracil （5-FU） was modified with arylsulfonyl groups. The presence of strong electron-withdrawing groups on benzene sulfonyl 5-FU greatly enhanced the binding selectivity （kG4-DNA/kds-DNA）. Such results provided new insights into the potential connections between the chemical structure of drug candidates and their anticancer activities.
HU QuanZHANG KeJunJIN HuiLeCHEN XiAnHU MaoLinWANG Shun
An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the modified Langmuir-Blodgett(LB)method,and the electrocatalytic oxidation of mononucleotide of guanosine 5′-monophosphate(GMP)on an ITO/TiO2-Ru electrode after Pd-photodeposition(denoted as ITO/TiO2-Ru/Pd)has been studied.Atomic force microscopy reveals that the single-layered hybrid film of TiO2 nanosheets/[Ru(phen)2(dC18bpy)] 2+is closely packed at a surface pressure of 25 mN m 1and has a thickness of(3.20±0.5)nm.X-ray photoelectron spectra show the formation of Pd nanoparticles on the surface of hybrid film with radii of 20–200 nm by the reduction of[Pd(NH3)4] 2+ under light irradiation.When it is applied to oxidize GMP,a larger catalytic oxidative current is achieved on the ITO/TiO2-Ru/Pd electrode at the external potential above 700 mV(vs.Ag|AgCl|KCl)in comparison with the naked ITO electrode and ITO/TiO2-Ru electrode.Such a result indicates that the Pd nanoparticles are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II)complexes,and thus develops the electron transfer efficiency and produces the enhanced redox current.
CHEN Xi' An WANG Shun LIN JuanJuan LIU AiLi HUANG ShaoMing
An indium tin oxide (ITO) electrode modified with monolayer clay/[Ru(phen)2(dC18bpy)]2+ (phen= 1,10-phenanthroline, dC18bpy = 4,4′-dioctadecyl-2,2′ bipyridyl) hybrid film has been fabricated by the Langmuir-Blodgett (LB) method. Atomic force microscopy revealed that the single-layered hybrid film of clay/[Ru(phen)2(dC18bpy)]2+ (denoted as Clay-Ru) was closely packed at a surface pressure of 25 mN-m-1 and had a thickness of 3.4±0.5 nm. Cyclic voltammograms showed that the redox current of Ru(Ⅱ) complex decreased when incorporated into the clay film, suggesting that the clay layer acts as a barrier against electron transfer. When applied to oxidizing the mononucleotide of guanosine 5′-monophosphate (GMP), a large catalytic oxidative current was achieved on the Clay-Ru(Ⅱ) modified ITO electrode at the external potential above 900 mV (vs. Ag|AgCl|KCl ) and, more significantly, this response was further enhanced by light irradiation (λ>360 nm), in which the photocurrent is increased about 11 times in comparison with that of a bare ITO. Mechanism of the photoelectrocatalytic effect was proposed in terms of the reduction of the photoelectrochemically generated Ru(Ⅲ) complex in the Clay-Ru film by GMP.
CHANG XueQin, WANG Shun, LIN DaJie, GUAN WeiPeng, ZHOU Huan & HUANG ShaoMing Nano-materials and Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027, China
