Amedeo Masci

Monolayers of natural and recombinant photosystem II on gold electrodes: Potentials for use as biosensors for detection of herbicides

Abstract Two methods for monolayer immobilization of photosystem II (PSII) isolated from thermophilic cyanobacteria Synechococcus elongatus and prospects for its use as a biosensor for detection of herbicides are reported: (i) immobilization based on recombinant (His)6‐tagged PSII coupled with nickel‐nitrilotriacetic acid (Ni‐NTA) chelator monolayer on Au electrode. (ii) immobilization based on the natural PSII coupled with the protein A‐anti‐D1 antibody modified Au electrode. Here, Cysteamine (CYS)‐self‐assembled monolayer (SAM)‐(NTA)‐PSII monolayers were compared with traditional bovine serum albumin (BSA)‐glutaraldehyde (GA)‐PSII crosslinked gel matrix and better performances of the derived electrochemical biosensors were pointed out. Better diffusion of inhibitors and mediators resulted in improved sensitivity, velocity of the response, and lower I 50 for herbicides.

Biosensors based on gold nanoelectrode ensembles and screen printed electrodes

Gold nanowires were synthesized within polycarbonate membranes according to an electroless deposition method, obtaining nanoelectrode ensembles (NEEs) with special electrochemical features. NEEs were coupled with home-produced carbon graphite screen printed electrodes and the electrochemical properties of the original nanoelectrode ensemble on screen printed substrate (NEE/SPS) assembly has been tested for sensors application. Glucose oxidase has been used as model enzyme in order to verify the feasibility of disposable gold NEE/SPS biosensors. Finally, different immobilisation and electrochemical deposition techniques based on either self assembled monolayers of cysteamine (CYS) or amino-propyl-triethoxysilane (APTES) and conductive polyaniline (PANI) molecular wires were used. Spatial patterning of the enzyme on the polycarbonate surface and of PANI wires on gold nanoelectrodes was obtained. Possible direct electron transfer between the enzyme and the PANI modified gold nanoelectrodes has been evaluated.

SCREEN PRINTED ELECTRODES FOR BIOSENSOR APPLICATION: REPRODUCIBILITY, SENSITIVITY AND STABILITY

Screen printed electrodes (SPEs) have been prepared in the Biosensor Lab @ ENEA, according to different layouts and configurations, i.e. front-back or concentric geometry. Different pastes and composition have been tested depending on the application and requirements for flow or batch measurements. In order to optimize the quality of the electrochemical response, graphite pastes and metal doped inks have been used, varying their physical features and composition. Preparation and analytical evaluation of SPEs probes have shown useful for specific detection of contaminants in complex matrices or for online monitoring their toxicological effect. Electrochemical comparison between commercially available probes and home-produced SPEs and statistical evaluation have been performed, to verify reproducibility at medium scale. Higher sensitivity and stability of these new probes have been achieved both in amperometric flow conditions and in voltammetric measurements. The results obtained show the possibility to use our SPEs, especially those based on Gwent Electronic Materials pastes for several reliable sensing applications.

Preparation of a composite anode for lithium-ion battery using a commercial water-dispersible non-fluorinated polymer binder

This paper describes a method for the preparation of a composite anode for lithium ion-battery using a commercial non-fluorinated water-dispersible polymer (Pattex PL50) as a binder. The benefits offered by using this polymer are related to its low cost and negligible toxicity. Furthermore, since the polymer is water dispersible, its adoption allows to replace the organic solvents, traditionally used in lithium-ion battery technology, with water thus decreasing the hazardousness of the preparation process as well as the production costs of the electrodes. In this paper, the preparation, characterization, and electrochemical properties of electrodes using the Pattex PL50 as the binder are described. A commercial high-capacity mesocarbon microbead graphite was selected as the electrode active material.

Developing a miniaturized continuous flow electrochemical cell for biosensor applications

The development of a miniaturized electrochemical cell for biosensor application regards both the structuring of an array of electrodes in a fluidic chamber and their connections to the control & processing unit The sensitivity of the chrono-amperometric measurement performed with the cell is increased by: (a) integrating the reference electrode on the same chip with the counter- and working- electrodes, (b) designing a specific pattern of the gold electrodes and (c) serially distributing them along the pipeline reservoir. Borosilicate glass is used as substrate for the electrodes, allowing, due to its transparency, an accurate and easy pad to pad alignment of the up-side-down chip versus a PCB soldered on a standard DIL 40 socket. This alignment is necessary to accomplish the elastomer-based-solderless electric contact, between chip and PCB. The solderless contact significantly improves both reliability and signal processing accuracy. The reservoir and its cover are micromachined out of silicone rubber respectively photosensitive glass in order to easy disassemble the fluidic chamber without any damage. Both thickness and elasticity of the photosensitive glass rend the device less brittle. A plug-in -plug-flow device with improved characteristics has been obtained with a modular structure that allows further extension of the number of electrodes.

Characterization of mixtures of sodium iron (II)/iron (III) phosphate as cathodes for sodium batteries

Sodium iron (II) phosphate/iron (III) phosphate mixtures with different Fe(II)/Fe(III) ratio were synthesized. X-ray diffraction, scanning electron micrographs, and thermal analysis were employed to characterize the samples. The electrochemical properties of electrodes prepared by using the samples as the active material were evaluated in lithium cells. One of the samples was electrochemical tested in sodium cells. The cell cyclability was evaluated as a function of the discharge rate. The values of capacity and voltage were employed for the calculation of the specific discharge energy and power.

Fabrication and characterization of composite electrodes for lithium-ion batteries

This paper reports the preparation and the characterization of composite electrodes based on TiO2 and LiFePO4. The electrodes were studied by using XRD, SEM, and charge/discharge cycles. The electrochemical tests comprised low rate cycling and cycling at different rates. The electrodes were used for the fabrication of lithium-ion batteries. Battery cells were assembled and electrochemical tested at various discharge rates to evaluate cell capacity and capacity retention as a function of the discharge rate.

A synthesis of LiFePO4 starting from FePO4 under reducing atmosphere

A fast and easy way to produce LiFePO 4 starting from FePO 4 , used as iron and phosphorus source, is proposed. 5% hydrogen is employed as a reducing agent and various compounds containing lithium as lithiation agents. The selected lithiation agents included: LiCl, CH 3 COOLi , LiOH, Li 2 S , LiH, and Li 2 CO 3 . Solid state synthesis is used for the LiFePO 4 preparation and the so obtained materials are structurally characterized by XRD. The materials are used to fabricate composite electrode and their specific capacity is evaluated by low rate galvanostatic charge/discharge cycles (C/10 rate). Among the various lithium salts, the acetate give rise to the LiFePO 4 with the best electrochemical performance. The morphology of this material is further investigated by SEM microscopy and the specific capacity is evaluated as a function of the discharge rate and the cycle number.

A synthesis of LiFePO4starting from FePO4under reducing atmosphere

A fast and easy way to produce LiFePO 4 starting from FePO 4 , used as iron and phosphorus source, is proposed. 5% hydrogen is employed as a reducing agent and various compounds containing lithium as lithiation agents. The selected lithiation agents included: LiCl, CH 3 COOLi , LiOH, Li 2 S , LiH, and Li 2 CO 3 . Solid state synthesis is used for the LiFePO 4 preparation and the so obtained materials are structurally characterized by XRD. The materials are used to fabricate composite electrode and their specific capacity is evaluated by low rate galvanostatic charge/discharge cycles (C/10 rate). Among the various lithium salts, the acetate give rise to the LiFePO 4 with the best electrochemical performance. The morphology of this material is further investigated by SEM microscopy and the specific capacity is evaluated as a function of the discharge rate and the cycle number.

A synthesis of LiFePO{sub 4} starting from FePO{sub 4} under reducing atmosphere

A fast and easy way to produce LiFePO 4 starting from FePO 4 , used as iron and phosphorus source, is proposed. 5% hydrogen is employed as a reducing agent and various compounds containing lithium as lithiation agents. The selected lithiation agents included: LiCl, CH 3 COOLi , LiOH, Li 2 S , LiH, and Li 2 CO 3 . Solid state synthesis is used for the LiFePO 4 preparation and the so obtained materials are structurally characterized by XRD. The materials are used to fabricate composite electrode and their specific capacity is evaluated by low rate galvanostatic charge/discharge cycles (C/10 rate). Among the various lithium salts, the acetate give rise to the LiFePO 4 with the best electrochemical performance. The morphology of this material is further investigated by SEM microscopy and the specific capacity is evaluated as a function of the discharge rate and the cycle number.