Flexible doctor blade-coated abiotic cathodes for implantable glucose/oxygen biofuel cells.

Implantable devices powered by batteries have been used for sixty years. In recent devices, lithium-based batteries are the most widely used power source. However, lithium batteries have many disadvantages in terms of safety, reliability, and longevity and require regular monitoring and substitution.

3D printable fully biomass-based composite using poly(furfuryl alcohol) as binder and cellulose as a filler.

Nowadays, composite materials are widely used in different sectors owing to their improved mechanical and functional properties compared to bulk materials and efficient manufacturing processes. Nevertheless, the majority of these materials are still petroleum-based, which is incompatible with the recent environmental awareness. As a result, in the current study, a fully biomass-based composite material was produced employing poly(furfuryl alcohol) (PFA) as a bio-based matrix coupled with cellulose powder as fillers and processing aid agent.

A fibrous cellulose paste formulation to manufacture structural parts using 3D printing by extrusion.

An optimized paste based on short natural cellulose fibers combined with carboxymethyl cellulose at a high dry content (42 wt.%) was implemented as a bio-based material for 3D printing by extrusion. The homogeneous paste exhibited a pronounced thinning behavior and yield stress; it was extruded using a screw extrusion-based direct ink writing system and could easily flow through a small nozzle.

Use of Cellulose Nanofibers as an Electrode Binder for Lithium Ion Battery Screen Printing on a Paper Separator.

Water-based inks were formulated using cellulose nanofibers as a binder in order to directly front/reverse print lithium ion cells on a paper separator. Moreover, the high cohesion of electrodes as provided by cellulose nanofibers allowed for the embedding metallic current collectors in the electrodes during the printing stage, in order to develop a one-step printing and assembling process. Positive and negative inks based on LiFePO₄, or graphite, respectively, and cellulose nanofibers, displayed rheological properties complying with a variety of printing processes, as well as with screen printing.

Fabrication of 3D conductive circuits: print quality evaluation of a direct ink writing process.

The use of conductive inks and direct writing techniques for the fabrication of electronic circuits on complex substrates is attracting ever increasing interest. However, the existing knowledge is only focused on the electrical performances of the produced smart objects with no direct correlation with the conductive paths morphology and printing conditions. In order to evaluate the printing quality of a direct writing process using an eccentric screw dispenser, a printing device for the deposition of silver paste on 3D objects was developed.

Screen-Printed Polyaniline-Based Electrodes for the Real-Time Monitoring of Loop-Mediated Isothermal Amplification Reactions.

Nucleic acid amplification testing is a very powerful method to perform efficient and early diagnostics. However, the integration of a DNA amplification reaction with its associated detection in a low-cost, portable, and autonomous device remains challenging. Addressing this challenge, the use of screen-printed electrochemical sensor is reported.

On the halt of spontaneous capillary flows in diverging open channels.

Due to their compactness and independence of exterior energy sources, capillary microsystems are increasingly used in many different scientific domains, from biotechnology to medicine and biology, chemistry, energy and space. Obtaining a capillary flow depends on channel geometry and contact angle. A general condition for the establishment of a spontaneous capillary flow in a uniform cross section channel has already been derived from Gibbs free energy.

Laccase-based biocathodes: Comparison of chitosan and Nafion.

Chitosan and Nafion(®) are both reported as interesting polymers to be integrated into the structure of 3D electrodes for biofuel cells. Their advantage is mainly related to their chemical properties, which have a positive impact on the stability of electrodes such as the laccase-based biocathode. For optimal function in implantable applications the biocathode requires coating with a biocompatible semi-permeable membrane that is designed to prevent the loss of enzyme activity and to protect the structure of the biocathode.

Capillary Flow Resistors: Local and Global Resistors.

The use of capillary systems in space and biotechnology applications requires the regulation of the capillary flow velocity. It has been observed that constricted sections act as flow resistors. In this work, we also show that enlarged sections temporarily reduce the velocity of the flow.

Laccase wiring on free-standing electrospun carbon nanofibres using a mediator plug.

Electrospun carbon nanofibres (CNFs) containing CNTs were produced by electrospinning and subsequent thermal treatment. This material was evaluated as a bioelectrode for biofuel cell applications after covalent grafting of laccase. Bis-pyrene-modified ABTS was used as a plug to wire laccase to the nanofibres leading to a maximum current density of 100 μA cm(-2).

Chitosan improves stability of carbon nanotube biocathodes for glucose biofuel cells.

We demonstrate a novel combined chitosan-carbon-nanotube-enzyme biocathode with a greatly enhanced and stable long-term current density of -0.19 mA mL(-1). The fibrous microstructure of the electrode improves the performance of the biocathode by creating a protective microenvironment, preventing the loss of the electrocatalytic activity of the enzyme, and providing good oxygen diffusion.

Encapsulation of a pressure-sensitive adhesive by spray-drying: microparticles preparation and evaluation of their crushing strength.

An industrial pressure-sensitive adhesive was microencapsulated by spray-drying using an aqueous colloidal ethylcellulose dispersion (Aquacoat® ECD) plasticised by triacetin to form the wall material. Unloaded (0:100) and adhesive-loaded (25:75) particles were produced in a Büchi B-191 mini spray-dryer with product yields of 62% and 57%, respectively. Microparticles were spherical and narrow sized with mean D₃,₂ diameters of 3.

Photoluminescence of 2,7-poly(9,9-dialkylfluorene-co-fluorenone) nanoparticles: effect of particle size and inert polymer addition.

Stable nanoparticle dispersions of 2,7-poly(9,9-dialkylfluorene-co-fluorenone) (PFFO) and of PFFO/cellulose acetate butyrate (CAB) mixtures with particle size ranging between 5 and 500 nm were prepared by miniemulsification in the presence of a cationic surfactant. Photoluminescence spectra of nanoparticle dispersions showed that the decrease of particle size and of the PFFO/CAB mass ratio induced the progressive suppression of the PFFO excimer emission band at 535 nm. This behavior was associated with the limited ordered structure and π-stacking arrangement of PFFO molecules when confined within nanoparticles smaller than 150 nm or in the presence of CAB molecules.

Preparation of highly hydrophobic and lipophobic cellulose fibers by a straightforward gas-solid reaction.

This work describes a very simple, rapid, and efficient approach to the hydrophobization and lipophobization of cellulose fibers through their reaction with gaseous trichloromethylsilane (TCMS). The characterization of the modified surface involved FTIR-ATR and solid-state (29)Si NMR spectroscopy, scanning electron microscopy (SEM), and contact angle measurements with different liquids. The modification generated an inorganic coating around the fibers, associated with the construction of a three-dimensional network of Si-O-Si bridges partly bound to the polysaccharide macromolecules.

Surfactant (TTAB) role in the preparation of 2,7-Poly(9,9-dialkylfluorene-co-fluorenone) nanoparticles by miniemulsion.

The role of tetradecyltrimethylammonium bromide (TTAB) and its partition between water, chloroform, and the chloroform/water interface during the miniemulsification of a photoluminescent polymer was investigated by indirect interfacial tension/elasticity measurements. Dynamic interfacial tension and elasticity measurements showed the presence of a gas-liquid phase transition at the chloroform/water interface and the formation of a rigid interface, which was supposed to promote emulsion stability. The parameters of the adsorption isotherms and the TTAB partition coefficient were obtained from surface tension isotherms.