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Fabrication process of CFOT and schematic illustration mechanism of CFOT for PTT/CDT synergistic therapy with GSH depletion and tumor targeting.

In the complex and severe tumor microenvironment, the antitumor efficiency of nanomedicines is significantly limited by their low-efficacy monotherapy, non-tumor targeting, and systemic toxicity. Herein, to achieve tumor-targeted and enhanced chemodynamic/photothermal therapy (CDT/PTT), we fabricated an "all-in-one" biocompatible transferrin-loaded cobalt ferrate nanoparticle (CoFe

Energy transfer was explored in a series of poly(phenylene ethynylene) (PPE) polymers with increasing lengths that were end-capped with thiophene-benzothiadiazole (TBT) groups to form fully conjuga...

Organic small molecules with near-infrared (NIR) absorption hold great promise as the phototheranostic agents for clinical translation by virtue of their inherent merits such as well-defined chemical structure, high purity and good reproducibility. Probes that happen to be based on cyanine dyes exhibit strong NIR-absorbing and efficient photothermal conversion, representing a new class of photothermal agents (PAs) for photothermal therapy (PTT), and taking into account the heat susceptibility of Mitochondria (Mito), we designed and prepared a mitochondria-targeted organic small molecule (Mito-BWQ) based on thiazole orange maternal unit that can effectively kill tumor cells through the hyperpyrexia generated in the lesions under exogenous laser irradiation. The Confocal laser scanning microscope was employed to determine the preferential targeting of Mito-BWQ to the mitochondria of MCF-7 cells and U87 cells. When subjected to 600 nm laser radiation, Mito-BWQ produced an increase in temperature in test systems and this increase was dependent on both the laser power and probe concentration. In vitro tests, cytotoxicity was observed when cells were incubated with Mito-BWQ and exposed to laser irradiation. The PTT in vivo also showed that Mito-BWQ performed remarkably in tumor inhibition. This study thus provides a vital starting point for the creation of thiazole orange-based PTT formulations and promotes further advances in the field of PAs-based anticancer research and therapy.

A corrugated organic light emitting diode (OLED) with enhanced light extraction is realized by incorporating a corrugated composite electron transport layer (ETL) consisting of two ETLs with different glass transition temperatures. The morphology of the corrugated structure is characterized with atomic force microscopy. The results show that the corrugation can be controlled by the layer thicknesses and annealing temperature. Compared with the control planar device, the corrugated OLED shows a more than 35% enhancement in current efficiency from 31 cd/A to 43 cd/A and a 20% enhancement in external quantum efficiency from 10% to 12% at 100 cd/m(2). In addition, the corrugated OLED also has a greatly improved operational stability. The LT90 lifetime of a device operated at 1000 cd/m(2) is improved greater than 100-fold in the corrugated OLED.

In this paper, the improved Hummers method was used to prepare graphene oxide (GO) and modified by cyclodextrin to prepare cyclodextrin-modified graphene oxide (CDGO) composites. The composites were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The adsorption properties of GO and CDGO for Pb2+ were measured by atomic absorption spectrophotometer. The results showed that the number of functional groups of the modified material and the adsorption sites increased. The adsorption capacities of GO and CDGO for lead were respectively 86.47mg/g and 165.52mg/g, which were consistent with the quasi-secondary kinetic model and Langmuir isotherm adsorption model. CDGO showed better adsorption capacity.

A series of π-conjugated oligomer-acceptor dyads were synthesized that feature oligo(phenylene ethynylene) (OPE) conjugated backbones end-capped with a naphthalene diimide (NDI) acceptor. The OPE segments vary in length from 4 to 8 phenylene ethynene units (PEn-NDI, where n = 4, 6 and 8). Fluorescence and transient absorption spectroscopy reveals that intramolecular OPE → NDI charge transfer dominates the deactivation of excited states of the PEn-NDI oligomers. Both charge separation (CS) and charge recombination (CR) are strongly exothermic (ΔG0CS ∼ −1.1 and ΔG0CR ∼ −2.0 eV), and the driving forces do not vary much across the series because the oxidation and reduction potentials and singlet energies of the OPEs do not vary much with their length. Bimolecular photoinduced charge transfer between model OPEs that do not contain the NDI acceptors with methyl viologen was studied, and the results reveal that the absorption of the cation radical state (OPE+•) remains approximately constant (λ ∼ 575 nm) regardl...

The interactions of two anionic poly(phenylene ethynylene) sulfonate-conjugated polyelectrolytes (mPPESO3– and pPPESO3–) with two alkynylplatinum(II) terpyridine complexes (Pt2+ and Pt3+) were studied. The Pt(II) complexes interact with helical mPPESO3– by intercalation within the polymer helix to form a “guest–host” ensemble. Titration of Pt(II) complexes into an aqueous solution of mPPESO3– gives rise to efficient quenching of the polymer’s fluorescence; meanwhile, triplet metal–metal-to-ligand charge transfer (3MMLCT) state emission from the intercalated Pt(II) complexes appears when the ensembles are excited into the polymer’s absorption band. The 3MMLCT state emission implies that the Pt(II) complexes aggregate or dimerize on the mPPESO3– scaffold. The responses of the mPPESO3– and Pt(II) complex ensembles to various proteins were examined by monitoring the mPPESO3– fluorescence change. Negatively charged proteins recover the mPPESO3– fluorescence more than the positively charged proteins under physi...

A new class of nonaggregating conjugated polyelectrolytes exhibits efficient fluorescence in aqueous solution. Analysis by optical spectroscopy and transmission electron microscopy reveals a unique structure-property correlation between oxygen substitution and aggregation.

A conjugated polyelectrolyte with symmetrically assembled hydrophilic and hydrophobic side groups along the backbone has been successfully synthesized and demonstrated significant photophysical tun...

As a cardiac pacemaker, the sinoatrial node spontaneously generates periodic electrical signals (action potentials) in its cells. The action potential generation is deeply related to various ion channels in cell membranes, and abnormalities of the ion channels cause sinus arrhythmia. We use the Zhang model of sinoatrial node cells to investigate the relation between the pacemaker rhythm (frequency of action potential generation) and ion channels. The Zhang model is described by the Hodgkin–Huxley nonlinear ordinary differential equations, and its parameter values vary between the periphery and center cells of the sinoatrial node. We analyze the bifurcation structure of the Zhang model and investigate the variability of the pacemaker rhythm and its sensitivity to ion channel conductance changes for both periphery and center cells. These results are also compared with the previous results of another sinoatrial node cell model: the Yanagihara–Noma–Irisawa model. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(11): 28–39, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11427

A conjugate polymer poly[p-(phenyleneethylene)-alt-(phenyleneazophenyleneethylene)] (PPEPAPE) containing azobenzene building block in the polymer backbone was synthesized via Sonogashira cross-coupling of 4,4′-diiodoazobenzene and 1,4-diethynyl-2,5-didodecyloxybenzene. All the monomers and the resulting polymer were well characterized. The polymer had a relatively high molecular weight and showed very good solubility (≧10 mg/mL) in common organic solvents. The photophysics of this polymer in solution and in film was investigated. The surface morphology of the films was studied by scanning electron microscope (SEM) and the relationship between the morphology and absorbance was discussed. This polymer has good film-forming property, broad absorbance and no emission, which might make it a good candidate for the photovoltaic material in the solar cell.

We report on quadrupolar (donor)2–acceptor sensitizers for dye-sensitized solar cells (DSSCs). The acceptor units are based on dithieno[2,3-a:3′,2′-c]phenazine and dithieno[3,2-a:2′,3′-c]phenazine coupled to thiophene donors. The optoelectronic and photophysical properties of two sets of isomers reveal a rigid structure for linear isomers and an efficient nonradiative decay for branched isomers. These sensitizers were integrated into DSSCs, and the quadrupolar structure is an operational design, as the IPCE reached up to 38% from 400 nm to 600 nm. The lengthening of the donor chain increases the efficiency, demonstrating the appeal of these oligomeric dyes for DSSCs.

The sinoatrial node (cardiac pacemaker) cell spontaneously generates periodic electrical signals (action potentials), and the action potential generation is deeply related to various ion channels in its cell membrane. The abnormalities of ion channels cause serious sinus arrhythmia, and such diseases are usually treated by applying drugs which have effects on ion channels. This paper uses the Zhang model of sinoatrial node cells to investigate the relation between pacemaker rhythm (frequency of action potential generation) and ion channels. The Zhang model is described by the Hodgkin-Huxley-type nonlinear ordinary differential equations, and its parameter values depend on the region (periphery or center) of the sinoatrial node. We analyze the bifurcation structure of the Zhang model, and examine the variabilities of pacemaker rhythm and its sensitivities on conductance changes of ion channels for both periphery and center cells. Moreover, these results are compared to the previous results of another sinoatrial node cell model (Yanagihara-Noma-Irisawa model). The above results are expected to be useful in the treatment of sinus arrhythmia.

Hodgkin and Huxley (1952) proposed the famous Hodgkin–Huxley (hereinafter referred to as HH) equations which quantitatively describe the generation of action potential of squid giant axon, although there are still arguments against it (Connor et al. 1977; Strassberg and DeFelice 1993; Rush and Rinzel 1995; Clay 1998). The HH equations are important not only in that it is one of the most successful mathematical model in quantitatively describing biological phenomena but also in that the method (the HH formalism or the HH theory) used in deriving the model of a squid is directly applicable to many kinds of neurons and other excitable cells. The equations derived following this HH formalism are called the HH-type equations.

Following the HH formalism introduced in Chap. 2, various kinds of HH-type models of neurons and other excitable cells are proposed (Canavier et al. 1991; Chay and Keizer 1983; Cronin 1987; Gerber and Jakobsson 1993; Hayashi and Ishizuka 1992; Keener and Sneyd 1998; Noble 1995; Rinzel 1990; Traub et al. 1991), and are analyzed (Alexander and Cai 1991; Av-Ron 1994; Bertram 1994; Bertram et al. 1995; Butera 1998; Canavier et al. 1993; Chay and Rinzel 1985; Doi and Kumagai 2005; Guckenheimer et al. 1993; Maeda et al. 1998; Rush and Rinzel 1994; Schweighofer et al. 1999; Terman 1991; Tsumoto et al. 2003, 2006; Yoshinaga et al. 1999). The HH-type equations include many variables depending on the number of different ionic currents and their gating variables considered in the equations, whereas the original HH equations possess only four variables (a membrane voltage, activation and inactivation variables of Na+ current and an activation variable of K+ current). Among the diverse family of HH-type equations, this chapter explores the dynamics and the bifurcation structure of the HH-type equations of heart muscle cells (cardiac myocytes).

What are models? The HH equations (2.3) are often called a physiological model, whereas the models appeared in the following sections are simplified models or abstract models. However, there is no model in which any simplifications or abstractions have not been made. Of course, many features of real neurons are ignored even in the HH equations. All models have their applicability and limits to describe natural phenomena. Therefore, all types of models whatever simplified or physiological, have their own values to model real phenomena. Starting with the BVP or FHN model which is a simplification of the HH equations, this chapter proceeds to several neuronal models with higher abstractions which are useful to tract some essential features of neurons.

In Chap. 2, we have explored the dynamics of the original Hodgkin–Huxley equations of a squid giant axon where only the parameter Iext was changed. The HH equations, however, include various constants or parameters whose values were determined based on physiological experiments, and thus the values inherently possess a certain ambiguity. Also, the “constants” are not really constant but change temporally. Thus, in this chapter, we study the effects of the change of the constants or parameters on the dynamics of the HH equations and consider the robustness and sensitivity of the equations; we study the bifurcation structure of the HH equations by changing their various parameters. To do so, in this chapter, we consider a slight modification of the original HH equations since the modification is mathematically more tractable.

Conjugated polyelectrolytes (CPEs) are semiconduciting organic polymers that feature polar/ionic solubilizing groups. We have demonstrated that CPEs can be used as light absorbing sensitizers atop nanocrystalline TiO2 in a dye-sensitized solar cell configuration leading to relatively efficient light-to-electrical power conversion. We have observed interesting corrleations between polymer chain length (degree of polymerization, DP) and solution state (molecularly dissolved vs. aggregated) on the DSSC efficiency. In order to better understand the interaction of CPEs with the metal-oxide interface, we have investigated the interaction of CPEs with single crystal TiO2 interfaces using high resolution atomic force microscopy imaging and photocurrent spectroscopy. Results of this work will be presented, with an emphasis on the fundamental factors that control the interaction and charge injection efficiency of CPEs at TiO2 interfaces.

A series of four quadrupolar (Donor)2Acceptor-acid (D2A) sensitizers, based on two acceptor cores (dibenzophenazine (DBP) or dithienophenazine (DTP)), were synthesized and their optoelectronic and photovoltaic properties were investigated. 4-Hexyl-thien-2-yl groups were employed as donor units, to produce regioisomers depending on their connecting position to the core. This architectural design leads to the investigation of the structure–property relationships of the dyes, both in solution and upon integration in dye-sensitized solar cells (DSSCs). Within sets of regioisomers, frontier orbital levels and absorption properties differed, but the photovoltaic performances of the DSSCs were similar. When examining the effect of the core, the electronic properties (absorbance, LUMO level) predicted a more favourable electron injection for the DTP systems. However, the open circuit voltages are ∼100 mV greater for the DBP systems.