Amperometric Biosensor and Front-End Electronics for Remote Glucose Monitoring by Crosslinked PEDOT-Glucose Oxidase

Focusing on the interplay between interface chemistry, electrochemistry, and integrated electronics, we show a novel low-cost and flexible biosensing platform for continuous glucose monitoring. The amperometric biosensing system features a planar three-electrode structure on a plastic substrate, and a wireless near-field communication-powered electronic system performing sensor analog front-end, A/D conversion, digital control, and display tasks. The working electrode is made of electropolymerized poly (3,4-ethylenedioxythiophene) film onto a polyethylene terephthalate/gold electrode followed by immobilization of cross-linked glucose oxidase by glutaraldehyde. The advantages offered by such…

On the Interaction between 1D Materials and Living Cells

One-dimensional (1D) materials allow for cutting-edge applications in biology, such as single-cell bioelectronics investigations, stimulation of the cellular membrane or the cytosol, cellular capture, tissue regeneration, antibacterial action, traction force investigation, and cellular lysis among others. The extraordinary development of this research field in the last ten years has been promoted by the possibility to engineer new classes of biointerfaces that integrate 1D materials as tools to trigger reconfigurable stimuli/probes at the sub-cellular resolution, mimicking the in vivo protein fibres organization of the extracellular matrix. After a brief overview of the theoretical models r…

Point-Of-Care Plastic Biosensor Devices using a PEDOT-modified Electrochemical Glucose Sensing Platform

There is an emerging global epidemic of diabetes that can be related to rapid increases in overweight, including obesity and physical inactivity. According to World Healthcare Organization, diabetes is a leading cause of blindness, amputation and kidney failure, while total deaths from diabetes are projected to rise by more than 50% in the next 10 years. To prevent life threatening and debilitating complications associated with diabetes, researchers are continuously involved in developing glucose biosensors. Hence, it is essential to develop a biosensor that can determine glucose levels having fast-response, high sensitivity and selectivity. Depending upon the transduction technique, a numb…

Core-shell Zn-doped TiO2-ZnO nanofibers fabricated via a combination of electrospinning and metal-organic chemical vapour deposition

Zn-doped TiO2 nanofibers shelled with ZnO hierarchical nanoarchitectures have been fabricated combining electrospinning of TiO2 (anatase) nanofibers and metal-organic chemical vapor deposition (MOCVD) of ZnO. The proposed hybrid approach has proven suitable for tailoring both the morphology of the ZnO external shell as well as the crystal structure of the Zn-doped TiO2 core. It has been found that the Zn dopant is incorporated in calcined electrospun nanofibers without any evidence of ZnO aggregates. Effects of different Zn doping levels of Zn-doped TiO2 fibers have been scrutinized and morphological, structural, physico-chemical and optical properties evaluated before and after the hierarc…

Colloidal lithography and Metal-Organic Chemical Vapor Deposition process integration to fabricate ZnO nanohole arrays

A complete set up of optimal process conditions for an effective colloidal lithography/catalyst assisted MOCVD process integration is presented. It mainly focuses on the determination of the deposition temperature threshold for ZnO Metal-Organic Chemical Vapour Deposition (MOCVD) as well as the concentration of metal-organic silver (Ag) catalyst. Indeed, the optimization of such process parameters allows to tailor the ZnO film morphology in order to make the colloidal lithography/catalyst assisted MOCVD approach a valuable bottom up method to fabricate bi-dimensional ordered ZnO nanohole arrays. (C) 2010 Elsevier B.V. All rights reserved.

Integration of Metal Organic Chemical Vapour Deposition and Wet Chemical Techniques to Obtain Highly Ordered Porous ZnO Nanoplatforms

Large-area, highly ordered ZnO micropores-arrays consisting of ZnO nanotubes delimited by ZnO nanorods have been successfully fabricated and tested for protein sensing applications. ZnO seed layers have been deposited by Metal Organic Chemical Vapour Deposition and readily patterned by Colloidal Lithography to attain ZnO nanorods growth at selective sites by Chemical Bath Deposition. The used synthetic approach has been proven effective for the easy assembly of ZnO nanoplatforms into high-density arrays. Both patterned and unpatterned ZnO nanorods have been morphologically and compositionally characterised and, thus, tested for model studies of protein mobility at the interface. The pattern…

Effects of Metal-Organic Chemical Vapour Deposition grown seed layer on the fabrication of well aligned ZnO nanorods by Chemical Bath Deposition

Well aligned, long and uniform ZnO nanorods have been reproducibly fabricated adopting a two-steps Metal-Organic Chemical Vapour Deposition (MOCVD) and Chemical Bath Deposition (CBD) fabrication approaches. Thin (<100 nm) ZnO buffer layers have been seeded on silicon substrates by MOCVD and ZnO layers have been subsequently grown, in form of well textured nanorods, using CBD. It has been found that the structure and thickness of the seed layer strongly influence the final morphology and the crystal texturing of ZnO nanorods as well as the CBD growth rate. There is, in addition, a strong correlation between morphologies of CBD grown ZnO nanorods and those of the seed layer underneath. Thus, …

ZnO nanorod arrays fabrication via chemical bath deposition: Ligand concentration effect study

A new ligand, N, N, N', N'-tetramethylethylenediamine, has been used to grow ZnO nanorods on silicon substrates via a two steps approach. A preliminary seeding on silicon substrates has been combined with chemical bath deposition using a Zinc acetate - N, N, N', N'-tetramethylethylenediamine aqueous solution. The used diamino ligand has been selected as Zn(2+) complexing agent and the related hydrolysis generates the reacting ions (Zn(2-) and OH(-)) responsible for the ZnO growth. The seed layer has been annealed at low temperature (<200 degrees C) and the ZnO nanorods have been grown on this ZnO amorphous layer. There is experimental evidence that the ligand concentration (ranging from 5 t…

Printing ZnO Inks: From Principles to Devices

Solution-based printing approaches permit digital designs to be converted into physical objects by depositing materials in a layer-by-layer additive fashion from microscale to nanoscale resolution. The extraordinary adaptability of this technology to different inks and substrates has received substantial interest in the recent literature. In such a context, this review specifically focuses on the realization of inks for the deposition of ZnO, a well-known wide bandgap semiconductor inorganic material showing an impressive number of applications in electronic, optoelectronic, and piezoelectric devices. Herein, we present an updated review of the latest advancements on the ink formulations an…

Ultrathin and nanostructured ZnO-based films for fluorescence biosensing applications

The fluorescence-based sensing capability of ultrathin ZnO-SiO(2) nanoplatforms, deposited by an integrated approach of colloidal lithography and metal organic chemical vapor deposition, has been investigated upon adsorption of fluorescein-labeled albumin, used as model analyte biomolecule. The protein immobilization process after spontaneous adsorption/desorption significantly enhances the green emission of the different ZnO-based films, as evidenced by scanning confocal microscopy, corresponding to a comparable protein coverage detected by X-ray photoelectron spectroscopy. Moreover, experiments of fluorescence recovery after photobleaching evidence that the protein lateral diffusion at th…

Spectroscopic and Theoretical Study of the Grafting Modes of Phosphonic Acids on ZnO Nanorods

Metal oxides are versatile substrates for the design of a wide range of SAM-based organic-inorganic materials among which ZnO nanostructures modified with phosphonic SAM are promising semiconducting systems for applications in technological fields such as biosensing, photonics, and field-effect transistors (FET). Despite previous studies reported on various successful grafting approaches, issues regarding preferred anchoring modes of phosphonic acids and the role of a second reactive group (i.e., a carboxylic group) are still a matter of controversial interpretations. This paper reports on an experimental and theoretical study on the functionalization of ZnO nanorods with monofunctional alk…

Superhydrophobic TiO2/Fluorinated Polysiloxane Hybrid Coatings with Controlled Morphology for Solar Photocatalysis

Abstract Technological applications of polysiloxane coatings have been influenced by their intrinsic low surface energy, which increases their water repellence. Accurate control of composition and interfacial properties through the introduction of perfluorinated moieties further lowers the polysiloxane surface energy, while mixing with metal oxide nanoparticles enhances roughness, resulting in a great potential in the development of superhydrophobic materials for photocatalysis. Herein, a series of hydrophobic and superhydrophobic hybrid coatings were prepared by dehydrocoupling and hydrosilylation reactions of polymethylhydrosiloxane with 1H,1H,2H,2H‐perfluorooctyltriethoxysilane and 1,3-d…

Method for polyamide synthesis

Recent advances in upscalable wet methods and ink formulations for printed electronics

This review deals with the use of solution processing approaches for organic electronics with a focus on material ink formulations as well as on their applicability. The solution processing techniques include methods like gravure printing, screen printing and ink-jet printing. Basic principles of each approach are understood and fundamental correlations between material (metals, semiconductors, and dielectrics) ink properties and final device performances can be drawn. Nevertheless, solution processing methods have the potential to evolve as the most promising tools in organic device fabrication techniques and have already been applied successfully in the fields of organic thin film transis…

Fabrication and characterisation of ZnO nanostructures: from nanoscale building blocks to hybrid nanomaterials - towards emerging technologies in sensing applications

Metal oxide nanostructures characterized by multiple morphologies and structures are at the forefront of applications driven nanotechnology research. In particular, they represent a versatile solution for performance enhancement and applications in multifunctional devices and offer distinct advantages over their bulk counterparts. The current state in ZnO nanomaterials research and its impact in nanotechnology and modern engineering are discussed through the lens of con-tinuing technological advances in synthetic techniques allowing to obtain the material with predefined specific set of criteria including size, functionality, and uniqueness. Aim of this research activity is fabrication and …

SUPERHYDROPHOBIC TIO2-FLUORINATED POLYSILOXANE NANOCOMPOSITES WITH PHOTOCATALYTIC CLEANING ACTIVITY FOR CULTURAL HERITAGE APPLICATIONS

ACID-BASE INTERACTIONS AND THEIR ROLE IN FORECASTING OF POLYMER COMPOSITES ADHESION PROPERTIES

Acid-base properties of wide range of polymers and adhesion systems based on polymers, polymer composites and metals were investigated. Composite materials based on high and low density polyethylenes, ethylene copolymers, other carbochain and heterochain polymers, synthetic rubber and their based on composites, epoxy composites, cured with a wide range of curing agents were used as adhesives. By using the contact angle of test liquids the values of the dispersion, acid-base, acid and base components of the surface free energy were calculated and the acidity parameter was estimated by means of van Oss-Chaudhury-Good and E. Berger methods respectively. Effect of composition on acidity and bas…