A far-red, photo- and bio-stable fluorescent marker selective to the endoplasmic reticulum and its application to tunicamycin-treated HeLa cells.

Herein, we developed an ER selective fluorescent ERp that exhibited a sharp fluorescence emission in the far-red region and high photo- and bio-stability in biological milieu. Its emission is insensitive to pH change and localized in the ER of the cells. Furthermore, it successfully demonstrated that the ER membrane is rapidly reorganized in the perinuclear region by an ER stress inducer, tunicamycin.

A self-calibrating bipartite viscosity sensor for mitochondria.

A self-calibrating bipartite viscosity sensor 1 for cellular mitochondria, composed of coumarin and boron-dipyrromethene (BODIPY) with a rigid phenyl spacer and a mitochondria-targeting unit, was synthesized. The sensor showed a direct linear relationship between the fluorescence intensity ratio of BODIPY to coumarin or the fluorescence lifetime ratio and the media viscosity, which allowed us to determine the average mitochondrial viscosity in living HeLa cells as ca. 62 cP (cp). Upon treatment with an ionophore, monensin, or nystatin, the mitochondrial viscosity was observed to increase to ca. 110 cP.

Confinement effects of P3HT in nanochannels and their implications for bulk heterojunction solar cells.

We studied the properties of regioregular P3HT conducting polymers with three different molecular weights infiltrated into the pores of mesoporous titania thin films. The titania thin films, prepared by self-organization of titania species with a non-ionic triblock copolymer F127 followed by calcination to remove organics, have arrays of 7 nm vertical nanochannels. The UV-Vis spectra of the P3HT-titania nanocomposite films revealed that the interstrand interactions between P3HT chains were weakened by the infiltration. Such an effect increases as the molecular weight of P3HT increases and as the infiltration temperature increases. Consequently, the efficiency of the solar cells, assembled by using the P3HT infiltrated mesoporous titania thin films, was the highest with the smallest P3HT, contrary to the generally accepted practice of using high molecular weight P3HT for forming bulk heterojunction solar cells.

Heteroleptic binuclear palladium(II) and platinum(II) complexes containing 1,2-bis(diphenylphosphino)acetylene and 1,2-benzenedithiolates: syntheses, crystal structures, electrochemistry and photoluminescence properties.

A series of heteroleptic binuclear Pd(ii) and Pt(ii) complexes, [M(bdts)](2)(micro-dppa)(2) (M = Pd () and Pt (); dppa = 1,2-bis(diphenylphosphino)acetylene = Ph(2)PC[triple bond, length as m-dash]CPPh(2); bdts = 1,2-benzenedithiolate (bdt: a), 3,4-toluenedithiolate (tdt: b) and 1,4-dichloro-2,3-benzenedithiolate (Cl(2)bdt: c), containing two square-planar MP(2)S(2) cores were prepared using (MCl(2))(2)(micro-dppa)(2) (M = Pd () and Pt ()) and the corresponding 1,2-benzenedithiols, and characterized by spectroscopic methods including FT-IR, Raman, UV-vis, MALDI-TOF-MS, (31)P{(1)H} and/or (195)Pt{(1)H} NMR spectroscopy. X-Ray crystal structure analyses for complexes and revealed that C1C2C4C3 is twisted in two ways with a torsion angle of 21.6-30.7 degrees for 3a, 4a, and 4b and about 42 degrees for 3c and 4c, and that their crystals are racemic mixtures. Due to the more electronegative chloride atoms in the ligand, complexes and show higher nu(M-S) vibrational frequencies in their Raman spectra, smaller spin-spin coupling constants (J(Pt-P)) in their (195)Pt{(31)P} NMR spectra and higher anodic potentials (E(pa)) in their cyclic voltammograms than complexes 3a, 3b, 4a and 4b. Moreover, only complex containing the chlorinated ligand and Pt(ii) ion exhibits luminescence (lambda(ob) = 610 nm and lambda(ex) = 440 nm) in the solid state at 298 K. This emissive transition can be assigned as the d-pi(dithiolate) metal-to-ligand charge transfer (MLCT) and the feasibility of this spin-forbidden transition is ascribed to the effective spin-orbit coupling of ligand c containing heavy chloride atoms and the large spin-orbit coupling in Pt(ii).

A mesoporous silica thin film as uptake host for guest molecules with retarded release kinetics.

Uptake and release processes of various fluorescent rhodamine dyes and antitumor drugs to/from an ordered mesoporous silica film are investigated by means of UV/Vis absorption and fluorescence spectroscopies. The pores in the 160 nm-thick silica film strongly withdraw the dyes from water, thus allowing the storage of several micrograms of guest molecules per square centimeter of film. The binding equilibrium of the dyes follows a Langmuir-type adsorption. The dissociation constant, K(d), and the maximum binding amount to the film, N(ads)(infinity), are determined by fitting the binding curves. The release kinetics of the guests from the film to a simulated body fluid (SBF) solution follows a bimodal first-order exponential behavior. The release kinetics from the mesoporous thin film is remarkably retarded relative to that from mesoporous powders. Among all the studied dyes, rhodamine 101 is released most slowly, which implies that the release rate depends not only on the interactions between the guests and the silica surface, but also on intermolecular interactions between the guest molecules. Comparison of the release kinetics of different antitumor drugs, such as actinomycin D and mitoxantrone, into an SBF solution shows that mitoxantrone is released much slowly. This slower release is attributed to the positive molecular charge and the formation of dimers in the pores.

Mesoporous titania thin film with highly ordered and fully accessible vertical pores and crystalline walls.

We report the preparation of mesoporous titania thin films with the R$\bar 3$m pore structure derived from the Im$\bar 3$m self-assembled ordering of the titania species and an EO(106)PO(70)EO(106) triblock copolymer. The films were spin-cast and then aged at 18 degrees C at a relative humidity of 70 %, which led to the orientation of the Im$\bar 3$m structure with the [111] direction perpendicular to the substrates. The [111] body-diagonal channels became vertical channels upon calcination at 400 degrees C, thus leading to thin films with vertical channels. The pores are ordered over a large area of up to 1 mum(2). The titania films can be formed on various types of substrates. By using a titania film formed on a Pt-coated Si wafer as a template, we produced by an electrochemical-deposition technique arrays of gold nanowires, whose morphology suggests that most of the pores of the titania thin films are accessible. The pore structure of vertical channels is stable up to 600 degrees C, at which temperature the wall materials crystallize into anatase.

A hydrophobic ligand-binding protein of the Taenia solium metacestode mediates uptake of the host lipid: implication for the maintenance of parasitic cellular homeostasis.

Parasitic organisms are incapable of de novo fatty acid synthesis due to a down-regulated expression of enzymes involved in the oxygen-dependent pathway. We investigated the uptake of host lipids by a 150-kDa hydrophobic ligand-binding protein (HLBP) of Taenia solium metacestode, an agent causative of neurocysticercosis. The protein was found to be a hetero-oligomeric complex consisting of multiple subunits (M(r) 7, 10, and 15 kDa within pH 8.0-9.7), which may originate from four unique genes of 7- and 10-kDa gene families with 2-3 polymorphic alleles/paralogs. The 15-kDa protein represented glycosylated forms of the 10-kDa. With high binding affinity to lipid analogs, these subunits evidenced high-level sequence identity with other cestode HLBPs and form a novel clade associated with excretory-secretory type HLBP. In vitro experiments with viable worms suggested that the excreted 150-kDa protein might bind to lipids, and participate in the translocation of host lipids across the syncytial membrane. This process was substantially inhibited by the specific anti-150 kDa antibodies. The protein was localized in the parasite syncytium and in the lipid droplets within host granuloma wall, where significant lipase activity was expressed. HLBP-mediated uptake of the host lipid may be critical for the parasite survival and thus could be targeted by chemotherapeutics and/or vaccine.

Crystal structure and spectroscopic study of novel two- and three-dimensional photoluminescent Eu(III)-adipate compounds.

Two new photoluminescent compounds with the formulas of [Eu(2)(adipate)(3)(H(2)O)].H(2)O (1) and [Eu(2)(adipate)(3)(4H(2)O)] (2) were synthesized by using Eu(III) chloride and adipic acid under hydrothermal reaction conditions in aqueous solution. Compound 1, a 3-D layered framework, possesses infinite Eu-O-Eu polyhedral chains and self-assembled adipate ligands between Eu-O layers. Compound 2 has dimeric Eu(2)O(16) units interconnected by adipate ligand, resulting in 2-D open frameworks with a cavity among the ligands. Crystal data 1: monoclinic space group C2/c, with a = 14.2486(12) A, b = 8.2733(7) A, c = 39.298(2) A, beta = 99.530(6) degrees, and Z = 8. 2: monoclinic space group P2(1)/c, with a = 11.661(4) A, b = 14.011(3) A, c = 9.013(4) A, beta = 110.87(3) degrees, and Z = 2. The ligand conformations of two Eu(III)-adipate (1 and 2) compounds present anti/anti/anti, gauche/anti/gauche, and intermediate forms. Both compounds 1 and 2 showed strong red luminescence upon excitation, and their luminescence decay involves the multiphonon relaxation mechanism.

Highly sensitive and simple fluorescence staining of proteins in sodium dodecyl sulfate-polyacrylamide-based gels by using hydrophobic tail-mediated enhancement of fluorescein luminescence.

Fluorescein has an extremely low luminescence intensity in acidic aqueous media. However, when it was bound to proteins, subsequent increase of luminescence intensity took place. Furthermore, when a hydrophobic tail, such as aliphatic hydrocarbons, was introduced to fluorescein, more dramatic increase of luminescence intensity was observed upon binding to proteins. In the present study, by utilizing this luminescence enhancement, three hydrophobic fluorescein dyes (5-dodecanoyl amino fluorescein, 5-hexadecanoyl amino fluorescein, and 5-octadecanoyl amino fluorescein) were examined as noncovalent fluorescent stains of protein bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Effective incorporation of the dyes to proteins in gels was accomplished either simply by adding dyes at the protein fixation step, or by treating gels with a staining solution after the fixation. The sensitivity of this staining method using the fluorescein derivatives was approximately 1 ng/band for most proteins. For some cases, protein bands containing as low as 0.1 ng were successfully visualized. In addition, the detection sensitivity showed much less protein-to-protein variation than silver staining. This new staining method was also successfully applied to two-dimensional electrophoresis of rat brain proteins. Its overall sensitivity was comparable to that of silver staining.