Ji-Lin Lu

Background eliminated signal-on electrochemical aptasensing platform for highly sensitive detection of protein

Using platelet-derived growth factor B chain dimer (PDGF-BB) as the model target, a background current eliminated electrochemical aptameric sensing platform for highly sensitive and signal-on detection of protein is proposed in this paper. Successful fabrication of the biosensor depends on ingenious design of aptamer probe, which contains the aptamer sequence for PDGF-BB and the recognition sequence for EcoRI endonuclease. In the absence of PDGF-BB, the ferrocene labeled aptamer probe folds into a hairpin structure and forms a recognition site for EcoRI. By treatment with endonuclease, the specific and cleavable double-stranded region is cut off and redox-active ferrocene molecule is removed from the electrode surface, and almost no peak current is observed. When binding with target protein, the designed aptamer probe changes its conformation and dissociates the recognition double strand. The integrated aptamer probe is maintained when exposing to EcoRI endonuclease, resulting in obvious peak current. Therefore, a signal-on and sensitive sensing strategy for PDGF-BB detection is fabricated with eliminated background current. Under the optimized experimental conditions, a wide linear response range of 4 orders of magnitude from 20pgmL(-1) to 200ngmL(-1) is achieved with a detection limit of 10pgmL(-1). Moreover, the present aptameric platform is universal for the analysis of a broad range of target molecules of interest by changing and designing the sequence of aptamer probe.

DNA binding, photocleavage behavior, and topoisomerase I inhibitory activity of Ru(II) complexes incorporating an asymmetric phenazine-type ligand

Two ruthenium complexes incorporating an asymmetric ligand, [Ru(L)2pipz]2+ (L = bpy (2,2′-bipyridine), phen (1,10-phenanthroline), pipz = 2-pyridine-1H-imidazo[4,5-b]phenazine), have been synthesized and characterized. The interactions of the two complexes with DNA have been investigated by UV–visible spectroscopy, fluorescence spectroscopy, and viscosity measurements. Both complexes bind to DNA by intercalation and efficiently cleave pBR322 DNA under irradiation. Singlet oxygen () was the main reactive oxygen species involved in DNA photocleavage. Topoisomerase inhibition and DNA strand passage assay demonstrated that both complexes can act as efficient catalytic inhibitors of DNA topoisomerase I. Graphical abstract

Synthesis, DNA-binding, and photocleavage studies of ruthenium(II) complexes with an asymmetric ligand

An asymmetric ligand (pdpiq = 2-(pyridine-2-yl)-6,7-diphenyl-1-H-imidazo[4,5-g]quinoxaline) and its ruthenium complexes with [Ru(L)2pdpiq]2+ (L = bpy (2,2′-bipyridine) or phen (1,10-phenanthroline)) have been synthesized and characterized by elemental analysis, ES-MS, and 1H NMR. The DNA-binding behaviors of these complexes were studied by spectroscopic methods and viscosity measurements. The results indicate that the complexes can intercalate into DNA base pairs. When irradiated at 365 nm, the two complexes promote the cleavage of plasmid pBR322DNA. The mechanism of DNA cleavage is an oxidative process by generating singlet oxygen.

DNA Interaction, Photocleavage and Topoisomerase I Inhibition by Ru(II) Complex with a New Ligand Possessing Phenazine Unit

A new ruthenium complex with a dppz-like ligand pyidppz, [Ru(bpy)2(pyidppz)]2+ (pyidppz = 2-(pyridine-2-yl)imidazo-[4,5-b]dipyrido-[3,2-a:2′,3′-c]phenazine) has been synthesized and characterized by ES-MS, elemental analysis, 1H NMR. Intercalative mode of the complex bound to calf thymus DNA has been supported by different spectroscopic methods and viscosity measurements. The introduction of phenazine unit may be one of the main reasons for the weak emission of Ru(II) complex in aqueous solution. Under irradiation, this complex can efficiently cleave DNA. And the photocleavage reaction of the complex is found to be inhibited in the presence of singlet oxygen scavenger. Topoisomerase inhibition and DNA strand passage assay demonstrated that [Ru(bpy)2(pyidppz)]2+ and its parent complex [Ru(bpy)2(pyip)]2+ (pyip = 2-(pyridine-2-yl)imidazo[4,5-f][1,10]phenanthroline) can act as efficient catalytic inhibitor of DNA topoisomerase I.

Hydrothermal synthesis of a chiral rare earth iodate (Gd(IO3)3 · H2O) showing the rare (3, 8)-connected (43)(4 · 62) (49 · 617 · 82) topology

In the presence of Cu(II) ions, a chiral rare earth iodate Gd(IO3)3 · H2O (crystallizing in P21 (no. 4) space group), was synthesized hydrothermally from Gd2O3 and HIO3; the structure is the topologically (3, 8)-connected (43)(4 · 62)(49 · 617 · 82) network, constructed from 3-connected trigonal nodes (I1, I3) and 8-connected tetragonal prism nodes (Gd1).

DNA Interaction and Photocleavage Properties of Ru (II) Complexes [Ru(bpy)2(pibi)]2+ and [Ru(phen)2(pibi)]2+

A new asymmetry ligand pibi (pibi = 2-(pyridine-2-yl)-1-H-imidazo[4,5-f]benzo[d]imidazolone) and its ruthenium complexes with [Ru(L)2(pibi)]2+ (L = bpy (2, 2′-bipyridine), phen (1, 10-phenanthroline)), have been synthesized and characterized. The binding of two complexes with calf thymus DNA has been investigated by spectroscopic and viscosity measurement. The results indicate that both complexes can bind to CT-DNA through intercalative mode. Under irradiation at 365 nm, both complexes can partly promote the photocleavage of plasmid pBR322DNA. The low singlet oxygen generation abilities of the two complexes may be the factor for the low DNA photocleavage abilities.

N,N'-Bis(pyridin-3-yl)terephthalamide-terephthalic acid (1/1).

In the title compound, C18H14N4O2·C8H6O4, both types of molecule lie on inversion centers. In the N,N′-bis(pyridin-3-yl)terephthalamide molecule, the pyridine ring forms a dihedral angle of 11.33 (9)° with the central benzene ring. In the crystal, N—H⋯O and O—H⋯N hydrogen bonds connect the components into a three-dimensional network.