Hydrocalumite Thin Films for Polyphenol Biosensor Elaboration

—Hybrid thin films based on Hydrocalu-mite (Ca 2 AlCl layered double hydroxide LDH) and tyrosinaseenzyme have been used for the elaboration of a high sensitive amperometric biosensor detecting polyphenols extracted from green tea. Structural properties of LDH nanomaterials were characterized by X-ray powder diffraction and Infra-Red spectroscopy, confirming its crystalline phase and chemical composition. Ca 2 AlCl-LDHs-thin films were deposited by spin-coating, and studied by atomic force microscopy to obtain information about the surface morphology of this host matrix before and after enzyme's immobilization. Electrochemical study using cyclic voltammetry and chronoamperometry shows good performances of the built-in biosensor with a high sensitivity for polyphenols concentrations ranging from 24 pM to 2.4 µM and a limit of detection of 1.2 pM. Index Terms—Amperometric biosensor, layered double hydroxide, tyrosinase, hybrid nanomaterial, atomic force microscopy

Amperometric Polyphenol Biosensor Based on Tyrosinase Immobilization on CoAl Layered Double Hydroxide Thins Films

International audienceAn amperometric biosensor based on tyrosinase immobilized on the sensor surface has been used for the detection of polyphenols extracted from green tea. The immobilization was ensured by the crosslinking method on thins films of CoAlSO 4 layered double hydroxide recovering screen-printed gold electrodes. Electrochemical measurements show that this biosensor is able to detect tea polyphenols by following the reduction of compounds enzymatically generated. Its response is linear in the concentration range of [0-2,4 µM] with high sensitivity and stability, since it retains 90% of its original response after 20 days

Image and many-body effects in ultra-thin gate insulator MOSFET with In0.53Ga0.47As channel material and their influence on gate leakage current

We study the influence of many-body and image force corrections on charge distribution, threshold voltage and tunnel current in fully-depleted silicon-on-insulator (FDSOI) ultra-thin gate insulator MOSFETs. We show that image correction slightly increases threshold voltage in Si MOSFETs and that the choice of dielectric constant (ie. static or dynamic) in image force correction can impact the sign of the correction in case of high- dielectric on In0.53Ga0.47As channel material. In addition, gate leakage current in two realistic CMOS devices is calculated by NEGF solver and the influence of image energy on tunnel transmission is discussed. Image energy is shown to increase leakage current at high gate voltage, because of barrier lowering effect ; while decreasing it at low Vg because of barrier width increase

Transcription factor MEF2C influences neural stem/progenitor cell differentiation and maturation in vivo

Emerging evidence suggests that myocyte enhancer factor 2 (MEF2) transcription factors act as effectors of neurogenesis in the brain, with MEF2C the predominant isoform in developing cerebrocortex. Here, we show that conditional knockout of Mef2c in nestin-expressing neural stem/progenitor cells (NSCs) impaired neuronal differentiation in vivo, resulting in aberrant compaction and smaller somal size. NSC proliferation and survival were not affected. Conditional null mice surviving to adulthood manifested more immature electrophysiological network properties and severe behavioral deficits reminiscent of Rett syndrome, an autism-related disorder. Our data support a crucial role for MEF2C in programming early neuronal differentiation and proper distribution within the layers of the neocortex