Syntheses and DNA-binding studies of two ruthenium(II) complexes containing one ancillary ligand of bpy or phen: [Ru(bpy)(pp[2,3]p)2](ClO4)2 and [Ru(phen)(pp[2,3]p)2](ClO4)2

Two new ruthenium(II) complexes of [Ru(bpy)(pp[2,3]p)2](ClO4)2 and [Ru(phen)(pp[2,3]p)2](ClO4)(2) (bpy=2,2'-bipyridine, phen=1,10-phenanthroline, pp[2,3]p=pyrido[2',3':5,6]pyrazino[2,3-f][1,10]phenanthroline) have been synthesized and characterized by elemental analysis and 1H NMR spectra. The calf thymus DNA-binding properties of the two complexes were investigated by UV-visible and emission spectroscopy, competitive binding experiments with ethidium bromide and viscosity measurements. The results indicate that the two complexes intercalate between the base pairs of the DNA tightly with intrinsic DNA-binding constants of 3.08 x 10(6) and 6.53 x 10(6) M(-1) in buffered 50 mM NaCl, respectively, which are much larger than 6.9 x 10(5) M(-1) for [Ru(bpy)2(pp[2,3]p)](ClO4)2 containing two ancillary ligands of bpy.     

Luminescent pH sensing and DNA binding properties of a novel ruthenium(II) complex

A new Ru(II) complex, [Ru(bpy)(2)(dhipH3)](ClO4)(2) (in which bpy=2,2'-bipyridine, dhipH(3)=3,4-dihydroxy-imidado[4,5-f][1,10]-phenanthroline), was synthesized and characterized, and the pH effect on the emission spectra of the complex was studied. The interaction of the complex with calf thymus DNA was investigated by UV-visible and emission spectroscopy, and viscosity measurements. The results suggest that the complex acted as a sensitive luminescent pH sensor and a strong ct-DNA intercalator with an intrinsic binding constant of (4.0+/-0.7) x 10(5) M(-1) in buffered 50 mM NaCl.     

Cytotoxicity, apoptosis, cellular uptake, cell cycle distribution, and DNA-binding investigation of ruthenium complexes

Three new ruthenium(II) polypyridyl complexes [Ru(bpy)(2)(BHIP)](2+) 1, [Ru(phen)(2)(BHIP)](2+) 2, and [Ru(dip)(2)(BHIP)](2+) 3 were synthesized and characterized. The cytotoxicity of the three complexes was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptosis induced by the complexes was studied by cell morphology and flow cytometry. The results showed that the percentage of apoptotic cells is 7.19%, 75.58%, and 3.51% in the presence of complexes 1, 2, and 3, respectively. The cellular uptakes were also performed and the results indicated that complexes 1, 2, and 3 can enter into the cytoplasm and also into the nucleus. The studies on antiproliferative mechanism showed the induction of S-phase arrest by complexes 1, 2, and 3. DNA-binding constants of these complexes with calf thymus DNA (CT-DNA) were determined to be 1.07 (± 0.47) × 10(5) M(-1) (s = 2.04), 1.21 (± 0.32) × 10(5) M(-1) (s = 1.88), and 2.75 (± 0.27) × 10(5) M(-1) (s = 2.17), respectively. Upon irradiation at 365 nm, complexes 1, 2, and 3 can induce cleavage of pBR322 DNA.     

DNA binding by Ru(II)–bis(bipyridine)–pteridinyl complexes

The interactions of five bis(bipyridyl) Ru(II) complexes of pteridinyl-phenanthroline ligands with calf thymus DNA have been studied. The pteridinyl extensions were selected to provide hydrogen-bonding patterns complementary to the purine and pyrimidine bases of DNA and RNA. The study includes three new complexes [Ru(bpy)(2)(L-pterin)](2+), [Ru(bpy)(2)(L-amino)](2+), and [Ru(bpy)(2)(L-diamino)](2+) (bpy is 2,2'-bipyridine and L-pterin, L-amino, and L-diamino are phenanthroline fused to pterin, 4-aminopteridine, and 2,4-diaminopteridine), two previously reported complexes [Ru(bpy)(2)(L-allox)](2+) and [Ru(bpy)(2)(L-Me(2)allox)](2+) (L-allox and L-Me(2)allox are phenanthroline fused to alloxazine and 1,3-dimethyalloxazine), the well-known DNA intercalator [Ru(bpy)(2)(dppz)](2+) (dppz is dipyridophenazine), and the negative control [Ru(bpy)(3)](2+). Reported are the syntheses of the three new Ru-pteridinyl complexes and the results of calf thymus DNA binding experiments as probed by absorption and fluorescence spectroscopy, viscometry, and thermal denaturation titrations. All Ru-pteridine complexes bind to DNA via an intercalative mode of comparable strength. Two of these four complexes-[Ru(bpy)(2)(L-pterin)](2+) and [Ru(bpy)(2)(L-allox)](2+)-exhibit biphasic DNA melting curves interpreted as reflecting exceptionally stable surface binding. Three new complexes-[Ru(bpy)(2)(L-diamino)](2+), [Ru(bpy)(2)(L-amino)](2) and [Ru(bpy)(2)(L-pterin)](2+)-behave as DNA molecular "light switches."     

The dichotomy in the DNA-binding behaviour of ruthenium(II) complexes bearing benzoxazole and benzothiazole groups

The substituted tris(bipyridine)ruthenium(II) complexes {[Ru(bpy)(2)(4,4'-bbob)](2+) and [Ru(bpy)(2)(5,5'-bbob)](2+) [where bpy=2,2'-bipyridine and bbob=bis(benzoxazol-2-yl)-2,2'-bipyridine] have been prepared and compared to the previously studied complex [Ru(bpy)(2)(4,4'-bbtb)](2+) [where bbtb=bis(benzothiazol-2-yl)-2,2'-bipyridine]. From the UV/VIS titration studies, Delta-[Ru(bpy)(2)(4,4'-bbob)](2+) displays a stronger association than the Lambda-isomer with calf-thymus DNA (ct-DNA). For [Ru(bpy)(2)(5,5'-bbob)](2+), there appears to be minimal interaction with ct-DNA. The results of fluorescence titration studies suggest that [Ru(bpy)(2)(4,4'-bbob)](2+) gives an increase in emission intensity with increasing ct-DNA concentrations, with an enantiopreference for the Delta isomer, confirmed by membrane dialysis studies. The fluorescent intercalation displacement studies revealed that [Ru(bpy)(2)(4,4'-bbob)](2+) and [Ru(bpy)(2)(5,5'-bbob)](2+) display a preference for more open DNA structures such as bulge and hairpin sequences. While Lambda-[Ru(bpy)(2)(4,4'-bbtb)](2+) has shown the most significant affinity for all the oligonucleotides sequences screened in previous studies, it is the Delta isomer of the comparable benzoxazole ruthenium(II) complex (Delta-[Ru(bpy)(2)(4,4'-bbob)](2+)) that preferentially binds to DNA.     

The effects of grafting of 2-pyridyl to [Ru(bpy)(2)(Hpip)](2+) on acid-base and DNA-binding properties: experimental and DFT studies

A new Ru(II) complex of [Ru(bpy)(2)(Hpip)](2+) {bpy = 2,2'bipyridine; Hppip = 2-(4-(pyridin-2-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} has been synthesized by grafting of 2-pyridyl to parent complex [Ru(bpy)(2)(Hpip)](2+) {Hppip = 2-(4-phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline}. The acid-base properties of [Ru(bpy)(2)(Hpip)](2+) studied by UV-visible and luminescence spectrophotometric pH titrations, revealed off-on-off luminescence switching of [Ru(bpy)(2)(Hpip)](2+) that was driven by the protonation/deprotonation of the imidazolyl and the pyridyl moieties. The complex was demonstrated to be a DNA intercalator with an intrinsic DNA binding constant of (5.56 ± 0.2) x 10(5) M-1 in buffered 50 mM NaCl, as evidenced by UV-visible and luminescence titrations, reverse salt effect, DNA competitive binding with ethidium bromide, steady-state emission quenching by [Fe(CN)6]4-, DNA melting experiments and viscosity measurements. The density functional theory method was also used to calculate geometric/electronic structures of the complex in an effort to understand the DNA binding properties. All the studies indicated that the introduction of 2-pyridyl onto Hpip ligand is more favorable for extension of conjugate plane of the main ligand than that of phenyl, and for greatly enhanced ct-DNA binding affinity accordingly.     

Synthesis, characterization, DNA-binding and photocleavage studies of [Ru(bpy)2(PPIP)]2+ and [Ru(phen)2(PPIP)]2+

A novel ligand 2-(4'-phenoxy-phenyl)imidazo[4,5-f][1,10]phenanthroline (PPIP) and its complexes [Ru(bpy)(2)(PPIP)](2+) (1) (bpy = 2,2'-bipyridine) and [Ru(phen)(2)(PPIP)](2+) (2) (phen = 1,10-phenanthroline) have been synthesized and characterized by mass spectroscopy, (1)H NMR and cyclic voltammetry. The interaction of two complexes with calf thymus DNA (CT-DNA) was investigated by spectroscopic and viscosity measurements. The results suggest that both complexes bind to DNA via an intercalative mode. Both complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA under irradiated.     

One-step electrochemically co-assembled redox-active [Ru(bpy)(2)(tatp)](2+)-BSA-SWCNTs hybrid film for non-redox protein biosensors

A redox-active [Ru(bpy)(2)(tatp)](2+)-BSA-SWCNTs (bpy=2,2'-bipyridine, tatp=1,4,8,9-tetra-aza-triphenylene, BSA=bovine serum albumin, SWCNTs=single-walled carbon nanotubes) hybrid film is fabricated on an indium-tin oxide (ITO) electrode via one-step electrochemical co-assembly approach. BSA is inherently dispersive and therefore served as the linking mediator of SWCNTs, which facilitate the redox reactions of [Ru(bpy)(2)(tatp)](2+) employed as a reporter of BSA. The evidences from differential pulse voltammetry, cyclic voltammetry, scanning electron microscope, emission spectroscopy and fluorescence microscope reveal that the [Ru(bpy)(2)(tatp)](2+)-BSA-SWCNTs hybrid can be electrochemically co-assembled on the ITO electrode, showing two pairs of well-defined Ru(II)-based redox waves. Furthermore, the electrochemical co-assembly of the [Ru(bpy)(2)(tatp)](2+)-BSA-SWCNTs hybrid is found to be strongly dependent on the simultaneous presence of BSA and SWCNTs, indicating a good linear response to BSA in the range from 6 to 50mgL(-1). The results from this study provide an electrochemical co-assembly method for the development of non-redox protein biosensors.     

In-situ produced ascorbic acid as coreactant for an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) electrochemiluminescence aptasensor

Herein, an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3)(2+)) electrochemiluminescence (ECL) aptasensor using in-situ produced ascorbic acid as coreactant was successfully constructed for detection of thrombin. Firstly, the composite of Ru(bpy)(3)(2+) and platinum nanoparticles (Ru-PtNPs) were immobilized onto Nafion coated glass carbon electrode, followed by successive adsorption of streptavidin-alkaine phosphatase conjugate (SA-ALP) and biotinylated anti-thrombin aptamer to successfully construct an ECL aptasensor for thrombin determination. In our design, Pt nanoparticles in Ru(bpy)(3)(2+)-Nafion film successfully inhibited the migration of Ru(bpy)(3)(2+) into the electrochemically hydrophobic region of Nafion and facilitated the electron transfer between Ru(bpy)(3)(2+) and electrode surface. Furthermore, ALP on the electrode surface could catalyze hydrolysis of ascorbic acid 2-phosphate to in-situ produce ascorbic acid, which co-reacted with Ru(bpy)(3)(2+) to obtain quite fast, stable and greatly amplified ECL signal. The experimental results indicated that the aptasensor exhibited good response for thrombin with excellent sensitivity, selectivity and stability. A linear range of 1 × 10(-15)-1 × 10(-8) M with an ultralow detection limit of 0.33 fM (S/N=3) was obtained. Thus, this procedure has great promise for detection of thrombin present at ultra-trace levels during early stage of diseases.     

Developing red-emissive ruthenium(II) complex-based luminescent probes for cellular imaging

Ruthenium(II) complexes have rich photophysical attributes, which enable novel design of responsive luminescence probes to selectively quantify biochemical analytes. In this work, we developed a systematic series of Ru(II)-bipyrindine complex derivatives, [Ru(bpy)(3-n)(DNP-bpy)(n)](PF(6))(2) (n = 1, 2, 3; bpy, 2,2'-bipyridine; DNP-bpy, 4-(4-(2,4-dinitrophenoxy)phenyl)-2,2'-bipyridine), as luminescent probes for highly selective and sensitive detection of thiophenol in aqueous solutions. The specific reaction between the probes and thiophenol triggers the cleavage of the electron acceptor group, 2,4-dinitrophenyl, eliminating the photoinduced electron transfer (PET) process, so that the luminescence of on-state complexes, [Ru(bpy)(3-n)(HP-bpy)(n)](2+) (n = 1, 2, 3; HP-bpy, 4-(4-hydroxyphenyl)-2,2'-bipyridine), is turned on. We found that the complex [Ru(bpy)(DNP-bpy)(2)](2+) remarkably enhanced the on-to-off contrast ratio compared to the other two (37.8 compared to 21 and 18.7). This reveals a new strategy to obtain the best Ru(II) complex luminescence probe via the most asymmetric structure. Moreover, we demonstrated the practical utility of the complex as a cell-membrane permeable probe for quantitative luminescence imaging of the dynamic intracellular process of thiophenol in living cells. The results suggest that the new probe could be a very useful tool for luminescence imaging analysis of the toxic thiophenol in intact cells.     

Optically active molecule-based magnets: enantioselective self-assembling, optical, and magnetic properties.

In this short communication we describe the synthesis and the optical and magnetic properties of optically active three dimensional (3D) bimetallic [Cr-Mn] networks [[Delta Cr(III) Delta Mn(II)(ox)(3)][Delta Ru(II)(bpy)(3)]ClO(4)](n)1 - Delta, [[Lambda Cr(III)Lambda Mn(II)(ox)(3)][Lambda Ru(II) (bpy)(3)]ClO(4)](n) 1 - Lambda and [[Delta Cr(III)Delta Mn(II)(ox)(3)][Delta Ru(II)(bpy)(2)p p y]](n) 2 - Delta,[[Lambda Cr(III)Lambda Mn(II)(ox)(3)][Lambda Ru(II)(bpy)(2)ppy]](n) 2 - Lambda (ox = oxalate, bpy = bipyridine, ppy = phenyl-pyridine).     

Synthesis, characterization and DNA binding studies of two mixed ligand complexes of ruthenium(II)

Two mixed ligand complexes [Ru(bpy)(2)(DMHBT)]Cl(2)(1) and [Ru(phen)(2)(DMHBT)]Cl(2) (2) (where DMHBT is 11,13-dimethyl-13H-4,5,9,11,14-hexaaza-benzo[b]triphenylene-10,12-dione) have been synthesized and characterized by electrospray ionization (ESI) mass, (1)H-(1)H correlation spectroscopy (COSY), electronic spectroscopy, fluorescence spectroscopy and cyclic voltammetry. Spectroscopic titration and viscosity changes of calf thymus (CT)-DNA in the presence of incremental amount of complexes 1 and 2 clearly demonstrate that both these complexes bind intercalatively to DNA, with binding constant 2.87+/-0.20 x 10(4)M(-1) and 1.01+/-0.20 x 10(5)M(-1) for complexes 1 and 2, respectively. All the experimental evidences suggest that the ancillary ligand 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) influences the intercalative binding of these complexes to DNA.     

Label-free and sensitive electrogenerated chemiluminescence aptasensor for the determination of lysozyme

A novel label-free electrogenerated chemiluminescence (ECL) aptasensor for the determination of lysozyme is designed employing lysozyme binding aptamer (LBA) as molecular recognition element for lysozyme as a model analyte and Ru(bpy)(3)(2+) as an ECL signal compound. This ECL aptasensor was fabricated by self-assembling the thiolated LBA onto the surface of a gold electrode. Using this aptasensor, sensitive quantitative detection of lysozyme is realized on basis of the competition of lysozyme with Ru(bpy)(3)(2+) cation for the binding sites of LBA. In the presence of lysozyme, the aptamer sequence prefers to form the LBA-lysozyme complex, the less negative environment allows Ru(bpy)(3)(2+) cations to be less bound electrostatically to the LBAs on the electrode surface, in conjunction with the generation of a decreased ECL signal. The integrated ECL intensity versus the concentration of lysozyme was linear in the range from 6.4×10(-10) M to 6.4×10(-7) M. The detection limit was 1.2×10(-10) M. This work demonstrates that using the competition of target protein with an ECL signal compound Ru(bpy)(3)(2+) for binding sites of special aptamer confined on the electrode is promising approach for the design of label-free ECL aptasensors for the determination of proteins.     

Long-lived photoinduced charge separation in new Ru(bipyridine)(3)(2+)-phenothiazine dyads

Synthesis and photophysical properties of three Ru(bpy)(3)(2+)-Ptz (bpy = 2,2'-bipyridine and Ptz = phenothiazine) dyads, where the number of Ptz groups increased from one to three, are reported. The MLCT absorption bands of these compounds were slightly red shifted compared to Ru(bpy)(3)(2+). The emission, however, was highly quenched and this is attributed to electron transfer from the Ptz moiety to the excited Ru(bpy)(3)(2+) to generate the charge separated state Ru(bpy)(3)(+)-Ptz (+). Observed electron transfer rates (k(et) > 10(8) s(-1)) were much faster than those previously reported (k(et) < 10(7) s(-1)) for linked Ru(bpy)(3)(2+)-Ptz systems. Compared to the previous systems, back electron transfer rates in these systems were about 100 times slower. This has enabled us to observe the charge separated state in nanosecond flash photolysis experiments. Transient absorptions assignable to Ru(bpy)(3)(+) and Ptz (+), having lifetimes in the range of 10-30 ns were observed. In order to explain the fast charge separation and slow charge recombination rates, formation of a folded conformer where the Ptz group attached to one bpy residue comes closer to and associates with another bpy moiety was invoked. A scheme which explains the fast electron transfer and slow recombination in this pre-associated state is proposed.     

Ruthenium(II)-phenanthroline-biotin complexes: synthesis and luminescence enhancement upon binding to avidin

We report the synthesis, characterization, and avidin-binding properties of two novel ruthenium complexes, [Ru(bpy)(2)(phen-biotin)][PF(6)](2) 1 and [Ru(phen)(2)(phen-biotin)][PF(6)](2) 2 (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline, phen-biotin = 5-(10-amidobiotinyl)-1,10-phenanthroline)). We demonstrate that both biotinylated compounds bind to avidin through their biotin moieties with high affinity and in a 4:1 ratio. The binding of compounds 1 and 2 to avidin results in an enhancement in luminescence intensity ( approximately 1.4x, approximately 1.6x, respectively), relative to the unbound biotinylated ruthenium complexes. This behavior is markedly different from biotinylated organic dyes, whose fluorescence is quenched upon binding to avidin. Thus, ruthenium-biotin complexes 1 and 2 can form the basis of new, simplified biotin-avidin assays, which involve luminescence detection of the relevant biotinylated molecule through cross-linking with avidin.     

Interaction of polypyridyl ruthenium (II) complex containing asymmetric ligand with DNA

A novel asymmetric bidentate ruthenium (II) complex, [Ru(bpy)(2)(PYNI)](2+) (bpy=2,2'-bipyridine, PYNI=2-(2'-pyridyl)naphthoimidazole), has been synthesized and characterized by elemental analysis, ES-MS (electrospray mass spectra) and (1)H NMR. The electrochemical behaviors of this complex were studied by cyclic voltammetry. DNA interaction studies suggest that [Ru(bpy)(2)(PYNI)](2+) binds to calf thymus DNA (CT-DNA) in an intercalative mode. Interestingly, this new Ru(II) complex has also been found to promote cleavage of plasmid pBR 322 DNA from the supercoiled form I to the open circular form II upon irradiation.     

Interaction of Lambda- and Delta-[Ru(bpy)2(pbmz)](PF6)2 with the oligonucleotide duplex d(CGCGAATTCGCG)2

The interaction of the enantiomeric complexes Lambda- and Delta-[Ru(bpy)(2)(pbmz)](PF(6))(2) (bpy=2,2'-bipyridine, pbmz=2-(2'-pyridyl)benzimidazole) with the DNA duplex d(CGCGAATTCGCG)(2) was investigated by means of 2D NMR techniques. The synthesis of the enantiomers was based on the optically pure complexes Lambda- and Delta-[Ru(bpy)(2)(py)(2)](2+) and were characterized by CD and NMR spectroscopy. NMR data indicate that both enantiomers bind weakly to the oligonucleotide, approaching from the minor groove at the centre of the helix. The perturbation of the B-DNA conformation is minor with an apparent absence of enantioselectivity. Molecular modelling calculations in conjunction with the NOE data support the suggestion that more than one binding modes are present. The imidazole amine group of the pbmz ligand is probably hydrogen bonded to the DNA phosphodiesteric backbone at the AATT step, and this may provide an explanation for the diminished enantioselectivity observed.     

Synthesis, characterization, and DNA-binding of chiral complexes delta- and lambda-[Ru(bpy)2(pyip)]2+

New chiral Ru(II) complexes delta and lambda-[Ru(bpy)(2)(pyip)](PF(6))(2) [(bpy = 2,2'-bipyridine; pyip = (2-(1-pyrenyl)-1H-imidazo[4,5-f] [1,10]phenanthroline] were synthesized and characterized by elemental analysis, (1)H NMR, ESI-MS, IR, and CD spectra. Their DNA-binding properties were studied by means of UV-vis, emission spectra, CD spectra and viscosity measurements. A subtle but detectable difference was observed in the interaction of both enantiomer with CT-DNA. Spectroscopy experiments indicated that each of these complexes could interact with the DNA. The DNA-binding of the Delta-enantiomer was stronger than that of Lambda-enantiomer. DNA-viscosity experiments provided evidence that both Delta- and Lambda-[Ru(bpy)(2)(pyip)](PF(6))(2) bound to DNA by intercalation. At the same time, the DNA-photocleavage properties of the complexes were investigated too. Under irradiation with UV light, Ru(II) complexes showed different efficiency of cleaving DNA.     

trans-[Ru(NO)(NH3)4(py)](BF4)3.H2O encapsulated in PLGA microparticles for delivery of nitric oxide to B16-F10 cells: Cytotoxicity and phototoxicity

The NO donor trans-[Ru(NO)(NH(3))(4)(py)](BF(4))(3).H(2)O (py=pyridine) was loaded into poly-lactic-co-glycolic acid (PLGA) microparticles using the double emulsification technique. Scanning electron microscopy (SEM) and dynamic light scattering revealed that the particles are spherical in shape, have a diameter of 1600nm, and have low tendency to aggregate. The entrapment efficiency was 25%. SEM analysis of the melanoma cell B16-F10 in the presence of the microparticles containing the complex trans-[Ru(NO)(NH(3))(4)(py)](BF(4))(3).H(2)O (pyMP) showed that the microparticles were adhered to the cell surface after 2h of incubation. The complex with concentrations lower than 1x10(-4)M did not show toxicity in B16-F10 murine cells. The complex in solution is toxic at higher concentrations (>1x10(-3)M), with cell death attributed to NO release following the reduction of the complex. pyMP is not cytotoxic due to the lower bioavailability and availability of the entrapped complex to the medium and its reducing agents. However, pyMP is phototoxic upon light irradiation. The phototoxicity strongly suggests that cell death is due to NO release from trans-[Ru(NO)(NH(3))(4)(py)](3+). This work shows that pyMP can serve as a model for a drug delivery system carrying the NO donor trans-[Ru(NO)(NH(3))(4)(py)](BF(4))(3).H(2)O, which can release NO locally at the tumor cell by irradiation with light only.     

Electrochemiluminescence determination of codeine or morphine with an organically modified silicate film immobilizing Ru(bpy)3(2+).

An ECL approach was developed for the determination of codeine or morphine based on tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)) immobilized in organically modified silicates (ORMOSILs). Tetramethoxysilane (TMOS) and dimethyldimethoxysilane (DiMe-DiMOS) were selected as co-precursors for ORMOSILs, which were then immobilized on a surface of glassy carbon electrode (GCE) by a dip-coating process. Ru(bpy)(3)(2+) was immobilized in the ORMOSIL film via ion-association with poly(p-styrenesulphonate). The ORMOSIL-modified GCE presented good electrochemical and photochemical activities. In a flow system, the eluted codeine or morphine was oxidized on the modified GCE and reacted with immobilized Ru(bpy)(3)(2+) at a potential of +1.20 V (vs. Ag/AgCl). The modified electrode was used for the ECL determination of codeine or morphine and showed high sensitivity. The calibration curves were linear in the range 2 x 10(-8)-5 x 10(-5) mol/L for codeine and 1 x 10(-7)-3 x 10(-4) mol/L for morphine. The detection limit was 5 x 10(-9) mol/L for codeine and 3 x 10(-8) mol/L for morphine, at signal:noise ratio (S:N)=3. Both codeine and morphine showed reproducibility with RSD values <2.5% at 1.0 x 10(-6) mol/L. Furthermore, the modified electrode immobilized Ru(bpy)(3)(2+) was applied to the ECL determination of codeine or morphine in incitant samples.