Free-standing flexible and biomimetic hybrid membranes for ions and ATP transport

The transport of metabolites across robust, flexible and free-standing biomimetic membranes made of three perforated poly (lactic acid) (pPLA) layers, separated by two anodically polymerized conducting layers of poly (3,4-ethylenedioxythiophene-co-3-dodecylthiophene), and functionalized on the external pPLA layers with a voltage dependent anion channel (VDAC) protein, has been demonstrated. The three pPLA layers offer robustness and flexibility to the bioactive platform and the possibility of obtaining conducing polymer layers by in situ anodic polymerization. The incorporation of dodecylthiophene units, which bear a 12 carbon atoms long linear alkyl chain, to the conducting layers allows mimicking the amphiphilic environment offered by lipids in cells, increasing 32% the efficiency of the functionalization. Electrochemical impedance measurements in NaCl and adenosine triphosphate (ATP) solutions prove that the integration of the VDAC porin inside the PLA perforations considerably increases the membrane conductivity and is crucial for the electrolyte diffusion. Such results open the door for the development of advanced sensing devices for a broad panel of biomedical applicationsPeer ReviewedPostprint (author's final draft

Investigation of the photoinduced electron injection processes for p-type triphenylamine-sensitized solar cells

We have carried out theor. investigation aiming at modeling the assessment of mechanisms of photoinduced processes in a recent p-type org. metal-free dye derived from the triphenylamine (P-1) structure. In the P-1 system, one uses the triphenylamine moiety as the electron donor, malononitrile as the electron acceptor, and a thiophene that plays the role of the conjugated chain. Basically, the difference between the P-1 dye and the common org. dyes used in the n-type DSSC field is the anchoring group located on the electron donor group. In a first step, DFT and TDDFT approaches have been exploited to calc. the key parameters controlling both the intramol. charge transfer (ICT) and hole transfer rate consts. in the Gurney-Gerischer-Marcus (GGM) formalism, for either a solvent-controlled adiabatic or a nonadiabatic electron transfer. These are: (i) the electronic coupling; (ii) the reorganization energies; and (iii) the variation of the Gibbs energy. The gathered results are in agreement with the exptl. trends. (i) The vertical ICT excited states energy has been calcd. at 2.67 eV, in perfect line with the expt. (2.65 eV). (ii) Two mechanisms can be conceived for the hole transfer and regeneration process. The first deals with the redn. of dye mol. at the excited state followed by an electron transfer from the reduced dye to the oxidized regenerator. The second implies a redox reaction between the excited dye and the oxidized regenerator, followed by an electron transfer from the cathode to the oxidized dye. (iii) Our theor. investigation suggests that the first mechanism is dominant. Secondly, we propose structural modifications improving the TPA-based DSSCs hole transfer efficiency and we show that an addnl. -CN graft on the malononitrile unit combined to the functionalization of the TPA moieties by -OMe groups (to give P-1b) should significantly improve the key parameters related to the electron injection. Indeed, for P-1b, we have noticed an increase of both the RLHE factor (0.907) and the injection driving force (-0.33 eV). This dye is therefore expected to be a very promising mol. in the p-type DSSC field

Photochromic properties of dithienylazoles and other conjugated diarylethenes

International audienc

DFT and TD-DFT investigation of IR and UV spectra of solvated molecules: comparison of two SCRF continuum models

We report the calculation of liquid-phase infrared (IR) and ultraviolet (UV) spectra in the framework of the solute's response to the reaction field of several solvents. In particular, we compare these two properties for the multipolar expansion model developed in the Nancy continuum model (NCM) and the polarized continuum model (PCM) scheme developed in Pise and Naples. All calculations are carried out at the (TD-)DFT/6-311G(2d,2p) level of theory. The cavity size used for modeling the solute effects on the IR and UV spectra are examined. To calibrate the solute cavity size, we have investigated the IR spectra of coumarin and of a set of 14 additional solutes of different size and polarity in several dielectrical surroundings. It turns out that: (i) PCM and NCM present an identical behavior when a common cavity is used to calibrate the models; and (ii) for both NCM and PCM models, the IR spectra are highly sensitive to the solute and solvent polarity. The UV/VIS investigation of coumarin derivatives demonstrates that both models provide close estimates of λmax independent of the solute cavity size

A TD-DFT investigation of UV spectra of pyranoidic dyes: a NCM vs PCM comparison

We report the calculation of the UV spectra of more than 40 substituted coumarins and chromones in solution. In particular, two solvent models are compared, the multipolar expansion model (NCM) developed in Nancy and the PCM scheme developed in Pisa and Napoli. All calculations are carried out at the NCM-TDPBE0/6-311G(2d,2p)//NCM-B3LYP/6-311G(2d,2p) and at the PCM-TDDFT/6-311+G(2d,2p)//PCM-DFT/6-311G(2d,2p) levels of theory. For most of the studied coumarin and chromone derivatives, there are at least two allowed excited states corresponding to transitions presenting a strong oscillator strength in the UV region. For the NCM treatment of substituted pyranones, the required accuracy for the design of molecules has been reached (we found a accuracy on the predictive data of 7 nm/0.08 eV for λmax(1) and 9 nm/0.18 eV for λmax(2)). Compared to PCM values, the NCM formalism provides λmax(1) predictions with equivalent accuracy and reliability. For λmax(2), the importance of diffuse functions is clearly demonstrated