A jellified alginate based capsule serves as biocompatible and biodegradable electrolyte system to gate an organic field-effect transistor fabricated on a flexible substrate. Such a system allows operating thiophene based polymer transistors below 0.5 V through an electrical double layer formed across an ion-permeable polymeric electrolyte. Moreover, biological macro-molecules such as glucose-oxidase and streptavidin can enter into the gating capsules that serve also as delivery system. An enzymatic bio-reaction is shown to take place in the capsule and preliminary results on the measurement of the electronic responses promise for low-cost, low-power, flexible electronic bio-sensing applications using capsule-gated organic field-effect transistors

A model for the electrical characteristics of Functional-Bio-Interlayer Organic Field-Effect Transistors (FBI-OFETs) electronic sensors is here proposed. Specifically, the output current-voltage characteristics of a streptavidin (SA) embedding FBI-OFET are modeled by means of the analytical equations of an enhancement mode p-channel OFET modified according to an ad hoc designed equivalent circuit that is also independently simulated with pspice. An excellent agreement between the model and the experimental current-voltage output characteristics has been found upon exposure to 5 nM of biotin. A good agreement is also found with the SA OFET parameters graphically extracted from the device transfer I-V curves.

A model for the electrical characteristics of Functional-Bio-Interlayer Organic Field-Effect Transistors (FBI-OFETs) electronic sensors is here proposed. Specifically, the output current-voltage characteristics of a streptavidin (SA) embedding FBI-OFET are modeled by means of the analytical equations of an enhancement mode p-channel OFET modified according to an ad hoc designed equivalent circuit that is also independently simulated with PSPICE. An excellent agreement between the model and the experimental current-voltage output characteristics has been found upon exposure to 5 nM of biotin. A good agreement is also found with the SA OFET parameters graphically extracted from the device transfer I-V curves

A new type of nanomaterial has been developed as antibacterial additive for food packaging applications. This nanocomposite is composed of copper nanoparticles embedded in polylactic acid, combining the antibacterial properties of copper nanoparticles with the biodegradability of the polymer matrix. Metal nanoparticles have been synthesised by means of laser ablation, a rising and easy route to prepare nanostructures without any capping agent in a liquid environment. As prepared, nanoparticle suspensions have been easily mixed to a polymer solution. The resulting hybrid solutions have been deposited by drop casting, thus obtaining self-standing antibacterial packages. All samples have been characterized by UV-Vis spectroscopy, X-ray photoelectron spectroscopy and electro-thermal atomic absorption spectroscopy. Ion release data have been matched with bioactivity tests performed by Japanese Industrial Standard (JIS) method (JIS Z 2801:2000) against Pseudomonas spp., a very common Gram-negative microbial group able to proliferate in processed food.

Gold nanoparticles stabilized on metal oxide supports have found a wide range of applications especially in heterogeneous catalysis and gas sensing. A facile methodology for the in situ electrodecoration of gold nanoparticles on metal oxide supports is presented herein. Metal oxides such as indium oxide (In2O3) and zirconia (ZrO2) nanoparticles are first prepared via the sol-gel route. Subsequently, gold nanoparticles are electrodeposited in situ on the surface of these metal oxides using a modified sacrificial Au-anode electrolysis procedure. Both pristine as well as electrodecorated metal oxides are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM, TEM). SEM images of electrodecorated metal oxides reveal successful deposition of gold nanoparticles on metal oxide supports. XPS shows that nano-sized gold is significantly available on the materials' surface and it is in the elemental oxidation state. Moreover, it is found that the electrodecoration of gold nanoparticles on metal oxide surfaces proceeds as a function of the concentration of hydroxyl groups on the surface of metal oxide supports.

Among the metal oxide semiconductors, ZnO has been widely investigated as a channel in thin film transistors (TFTs) due to its excellent electrical properties, optical transparency and simple fabrication via solution processed techniques. Herein, we are reporting a solution processable ZnO based thin-film transistor, gated through a liquid electrolyte having an ionic strength comparable to that of a physiological fluid. The surface morphology and chemical composition of the ZnO films upon exposure to water and phosphate buffer solution (PBS), are discussed in terms of operation stability and electrical performance of the ZnO TFT devices. Improved device characteristics upon exposure to PBS are associated with the enhancement of the oxygen vacancies in ZnO lattice, possibly due to Na+ doping. Moreover, dissolution kinetics of ZnO thin film in liquid electrolyte opens to possible applicability of these devices as active element in “transient” implantable systems.

Methods to immobilize proteins are of particular relevance for biosensing. In biosensors, proteins have to be assembled according to suitable architectures on solid surfaces such as electrodes, optical windows, or the organic semiconductor layer of electronic devices and their integrity and activity have to be preserved. This chapter deals with the use of immobilized proteins in several types of biosensors. The importance of molecular architecture control, particularly with synergistic combination of proteins and “other” materials, is evidenced. Different methodologies for protein assembly are described, highlighting the environmental applications of the protein based biosensors. Results from the literature, grouped into large areas covering optical and electrochemical biosensors and also sensing exploiting field-effect transistors, are reported. Layer by layer (LbL) immobilization of proteins on the transparent substrate of optical biosensors is proposed for its advantageous control of molecular architecture and versatility to accommodate layers having different functionalities. Covalent immobilization is evaluated as an alternative process for the controlled incorporation of the recognition element on/into the electrode surface, in the case of electrochemical transducers. Finally, the integration of immobilized proteins in electronic devices is presented, especially in the context of using field-effect transistors (FETs) for biosensing. It is hoped that this survey may assist researchers in choosing materials, molecular architectures, and detection principles, which may be tailored for specific applications.

Peripheral events in olfaction involve odorant binding proteins (OBPs) whose role in the recognition of different volatile chemicals is yet unclear. Here we report on the sensitive and quantitative measurement of the weak interactions associated with neutral enantiomers differentially binding to OBPs immobilized through a self-assembled monolayer to the gate of an organic bio-electronic transistor. The transduction is remarkably sensitive as the transistor output current is governed by the small capacitance of the protein layer undergoing minute changes as the ligand–protein complex is formed. Accurate determination of the free-energy balances and of the capacitance changes associated with the binding process allows derivation of the free-energy components as well as of the occurrence of conformational events associated with OBP ligand binding. Capacitance-modulated transistors open a new pathway for the study of ultra-weak molecular interactions in surface-bound protein–ligand complexes through an approach that combines bio-chemical and electronic thermodynamic parameters.

Bio-sensing represents one of the most attractive applications of carbon material based electronic devices; nevertheless, the complete integration of bioactive transducing elements still represents a major challenge, particularly in terms of preserving biological function and specificity while maintaining the sensor’s electronic performance. This review highlights recent advances in the realization of field-effect transistor (FET) based sensors that comprise a bio-receptor within the FET channel. A birds-eye view will be provided of the most promising classes of active layers as well as different device architectures and methods of fabrication. Finally, strategies for interfacing bio-components with organic or carbon nanostructured electronic active layers are reported.

Alkyl-methylimidazolium based ionic liquids are proposed as gating electrolytes in field-effect transistors and the ionic properties are seen to influence the devices electrical performance. Specifically, over a selection of different cations and anions correlations have been established between the ion-pairing occurring in the pure ionic-liquid and the intensity of the current circulating in the transistor channel in the on state. Ion-pairing was determined by means of pulse-gradient-spin-echo (PGSE) NMR experiments. Moreover, the effect of the ions chemical structure and hydrophobicity on the off-current and on the field-effect mobility as well as on the threshold voltage, are discussed. The occurrence of hysteresis in the current–voltage transfer curves is evaluated and associated to the electrolyte molar conductivity and the ions self-diffusion coefficients. The gained understanding allows to optimize the system reaching better device performance level. Moreover, thanks to the well-known bio-compatibility of this class of ionic liquids, application in electrolyte gated biosensors can be foreseen.

Gold (Au) nanoparticles stabilized on metal oxide supports offer superior catalytic activity and recyclability in organic catalysis. We report for the first time synthesis of indium oxide stabilized gold (Au@In2O 3) nanocatalysts using an electrochemical procedure and their application in homocoupling of arylboronic acids. In2O3 nanoparticles prepared via sol-gel process are subjected to sacrificial anode electrolysis (SAE) under inert condition for electrodeposition of nano Au on In2O3. Thus Au@In2O3 nanoparticles obtained are thermally annealed at high temperature to partially oxidize Au and to remove any surfactants. XPS results show the existence of both elemental (nano Au0) and cationic (Au3+) species in Au@In 2O3 nanocatalysts, while SEM images confirm the presence of nanoscale Au (<10 nm) particles on In2O3 surface. Au@In2O3 nanocatalysts are tested for arylboronic acids homocoupling under different conditions and it is found that they are highly active in organic medium with K2CO3 base and demonstrate excellent conversion (>97%) and selectivity (>98%). The catalyst recyclability and performance towards differently substituted arylboronic acids is also studied and a plausible mechanism of action is proposed.

Electrolyte-gated organic field-effect transistors are successfully used as biosensors to detect binding events occurring at distances from the transistor electronic channel that are much larger than the Debye length in highly concentrated solutions. The sensing mechanism is mainly capacitive and is due to the formation of Donnan's equilibria within the protein layer, leading to an extra capacitance (CDON) in series to the gating system.

Organic thin film transistors (OTFT) are metal-insulator-semiconductor field-effect transistors in which the semiconductor is a conjugated organic material. They are the subject of intense industrial research because their fabrication process is less expensive when compared with inorganic TFTs. Among the others, the organic material mostly employed in their construction consists of two semiconductor polymers, namely poly(3-hexylthiophene) (P3HT) and poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). Despite the large amount of experimental efforts in the characterization of the electronic properties of these devices, several questions regarding their morphological arrangement in bulk and at interfaces remain wide open. Here, we report results obtained by classical molecular dynamics simulations of P3HT and PBTTT inspired by OTFT fabrication techniques. In particular, we investigate how the annealing fabrication process and the presence of residual solvent molecules left over after spin coating might modify the morphology and the dynamics of the amorphous phase of these two polymers. Simulations of both polymer deposits at 300 K after annealing show an increase in the number of interdigitation events between the alkyl chains of two polymeric macromolecules; moreover, we find that the increased stability of the pi-pi stacking is caused by an improved layering of the films, which may account for the better charge transport properties reported in experiments. Our results strongly suggest that thin semiconductor films are required to boost the performances of the devices and that a minimal presence of residual solvent does not alter dramatically the microscopic structure and stability of the polymeric films.

There is an increasing interest in low cost, timesaving, yet reliable, point-of-care assays. Direct electronic, label-free transduction of bio-recognition events represents a compelling alternative offering miniaturization, easy data handling and processing. Low costs and versatility can be provided if organic electronic devices such as organic fi eld-effect transistors (OFETs) are used as transducers. [ 1 , 2 ] At the beginning, OFET sensors were mostly involved the detection of volatile chemical analytes, [ 3 , 4 ] while organic electronics allowed fabrication of sensing circuits on fl exible substrates. [ 5 , 6 ] However, bare OFET-sensor responses are based on weak interactions that are non-specifi c in nature. Specifi city can be achieved by endowing the OFET with receptor molecules capable of selectively interacting with given analytes.

Automobile exhaust gas emissions are causing serious damage to urban air quality in and around major cities of the world, which demands continuous monitoring of exhaust emissions. The chief components of automobile exhaust include carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons. Indium zirconate (InZrOx) and gold/indium zirconate (Au/InZrOx) composite nanopowders are believed to be interesting materials to detect these substances. To this end, characterization and gas sensing properties of InZrOx and Au/InZrOx composite nanopowders are discussed. InZrOx nanoparticles with In/Zr atomic ratio of 1.00 (±0.05) are synthesized via pH-controlled co-precipitation of In and Zr salts in aqueous ammonia. Gold (Au) nanoparticles are subsequently deposited on InZrOx using an in situ sacrificial Au electrolysis procedure. The products are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing performance of Au/InZrOx composite nanopowder is studied by depositing a thick powder film on interdigitated electrode structures patterned on SiC substrate to facilitate high temperature operation. The resistivity of the Au/InZrOx layer is the sensor signal, and the sensors could be operated at 500–600 °C, which is a suitable temperature range for engine exhaust measurements. The control sensing measurements reveal that Au/InZrOx composite nanopowder exhibits higher response towards 2–20 % O2 gas as compared to pristine InZrOx nanoparticles. Further studies show that when applied to exhaust gases such as CO and nitric oxide (NO), the response of Au/InZrOx sensors is significantly higher towards NO in this temperature range. Thus, sensor performance characteristics of Au/InZrOx composite nanopowder are promising in terms of their applications in automobile exhaust emission control.

In the present study, gold/surfactant core/shell colloidal nanoparticles with a controlled morphology and chemical composition have been obtained via the so-called sacrificial anode technique, carried out in galvanostatic mode. As synthesized Au-NPs had an average core diameter comprised between 4 and 8 nm, as a function of the electrochemical process experimental conditions. The UV–Vis characterization of gold nanocolloids showed clear spectroscopic size effects, affecting both the position and width of the nanoparticle surface plasmon resonance peak. The nanomaterial surface spectroscopic characterization showed the presence of two chemical states, namely nanostructured Au(0) (its abundance being higher than 90%) and Au(I). Au-NPs were then deposited on the top of a capacitive field effect sensor and subjected to a mild thermal annealing aiming at removing the excess of stabilizing surfactant molecules. Au-NP sensors were tested towards some gases found in automotive gas exhausts. The sensing device showed the largest response towards NOx, and much smaller – if any – responses towards interferent species such as NH3, H2, CO, and hydrocarbons.

A general method to obtain the efficient entrapment of mixtures of glyco-enzymes in calcium alginate hydrogel is proposed in this paper. As a proof of principle, three glyco-enzymes acting in series (trehalase, glucose oxidase and horseradish peroxidase) have been co-immobilized in calcium alginate beads. The release of the enzymes from the hydrogel mesh (leakage) is avoided by exploiting the enzymes aggregation induced by the concanavalin A. The aggregation process has been monitored by dynamic light scattering technique, while both enzyme encapsulation efficiency and leakage have spectrophotometrically been quantified. Obtained data show an encapsulation efficiency above 95% and a negligible leakage from the beads when enzyme aggregates are larger than 300 nm. Operational stability of “as prepared” beads has been largely improved by a coating of alternated shells of polycation poly(diallyldimethylammonium chloride) and of alginate. As a test for the effectiveness of the overall procedure, analytical bio-assays exploiting the enzyme containing beads have been developed for the optical determination of glucose and trehalose and Limit of Detection values of 0.2 uM and of 40 uM respectively have been obtained.

Biosystems integration into an organic field-effect transistor (OFET) structure is achieved by spin coating phospholipid or protein layers between the gate dielectric and the organic semiconductor. An architecture directly interfacing supported biological layers to the OFET channel is proposed and, strikingly, both the electronic properties and the biointerlayer functionality are fully retained. The platform bench tests involved OFETs integrating phospholipids and bacteriorhodopsin exposed to 1–5% anesthetic doses that reveal drug-induced changes in the lipid membrane. This result challenges the current anesthetic action model relying on the so far provided evidence that doses much higher than clinically relevant ones (2.4%) do not alter lipid bilayers’ structure significantly. Furthermore, a streptavidin embedding OFET shows label-free biotin electronic detection at 10 parts-per-trillion concentration level, reaching state-of-the-art fluorescent assay performances. These examples show how the proposed bioelectronic platform, besides resulting in extremely performing biosensors, can open insights into biologically relevant phenomena involving membrane weak interfacial modifications.

A polyanionic proton conductor, named poly(4-styrenesulfonic acid) (PSSH), was used to gate an Organic Thin-Film Transistor (OFET) based on p-type poly(2,5-bis(3-tetradecylthiophen-2-yl)thienol [3,2-b]thiophene) (pBTTT-C14) organic semiconductor (OSC). Different device configurations were evaluated and a bottom gate – top contact (BGTC) device was investigated as transducer for gas sensing measurements. The sensors׳ performance in terms of stability, repeatability and reproducibility were evaluated when the device was exposed to different concentrations of 1-butanol. Comparison with a conventionally gated OFET (SiO2 dielectric instead of PSSH) was also performed.

One- and two-dimensional carbon nanostructures, i.e. carbon nanotubes (CNTs) and graphene possess exceptional physical properties owing to their distinctive structure and atomic arrangement. High electrical conductivity, highly exposed surface area and stability of these carbon nanostructures institute them as the leading choice of nanomaterials for a number of electrical and industrial applications. Besides these carbon nanostructures are extremely sensitive towards minute changes in the surrounding gas atmosphere, i.e. their conductance (or resistance) varies greatly with the adsorption-desorption of gas molecules such as nitrogen oxides (NOx). This article critically reviews the most recent advances in NOx sensors based on one- and two-dimensional carbon nanostructures and nanohybrids as gas sensitive materials. The advantages and limitations of CNT- and graphene-based devices are briefly discussed in the light of recent literature. The potential and future perspectives of these devices are also outlined in this study.

21st century has already seen huge progress in science and technology of small, highly sensitive gas sensors, which can selectively detect environmental toxins like NOx – the oxides of nitrogen – a byproduct of fossil fuel combustion. Into this bargain, public became more health-aware and environmental bodies grew stricter, stimulating analytical and material scientists to find new strategies from material synthesis to fabrication of NOx sensors in order to produce fast and reliable gas detectors. To the scientists, semiconducting metal oxides, owing to their low cost, easy processing, high gas response, good electrical properties and above all tunable structure at the nanoscale, always presented a first-hand choice for sensor fabrication. This article presents an overview of the most recent developments in semiconducting NOx gas sensors based on these metal oxide nanostructures and their applications in vehicle exhaust and environmental monitoring. A strong emphasis is presented on chemiresistor and field effect transistor devices using semiconducting metal oxides as active layers. The performance levels of these NOx sensors are compared to those of other devices as well as other semiconductor materials. Furthermore, keeping in mind the ultimate user demands, limitations of the current sensor technologies and future strategies are discussed

The functioning principles of electronic sensors based on organic semiconductor field-effect transistors (OFETs) are presented. The focus is on biological sensors but also chemical ones are reviewed to address general features. The field-induced electronic transport and the chemical and biological interactions for the sensing, each occurring at the relevant functional interface, are separately introduced. Once these key learning points have been acquired, the combined picture for the FET electronic sensing is proposed. The perspective use of such devices in point-of-care is introduced, after some basics on analytical biosensing systems are provided as well. This tutorial review includes also a necessary overview of the OFET sensing structures, but the focus will be on electronic rather than electrochemical detection. The differences among structures are highlighted along with the implications on the performance level in terms of key analytical figure of merits such as: repeatability, sensitivity and selectivity

A Functional Bio-Interlayer Organic Field-Effect Transistor (FBI-OFET) sensor, embedding a streptavidin protein capturing layer, capable to perform label-free specific electronic detection of biotin at 3 part-per-trillion (mass fraction) or 15 pM, is here proposed. The response shows a logarithmic dependence on the analyte concentration along with a dynamic range spanning over five orders of magnitude. The optimization of the FBI analytical performances is achieved by depositing the capturing layer through a controllable Layer-by-Layer (LbL) assembly, while an easy processable spin-coating deposition is proposed for potential low-cost production of equally highly performing sensors. A Langmuirian adsorption based model allows to rationalize the analyte binding to the capturing layer whose analytical performances are discussed accordingly. The FBI-OFET device is shown to operate also with an antibody interlayer as well as with an ad hoc designed micro-fluidic system. These occurrences, along with the proven extremely high sensitivity and selectivity, open to FBI-OFETs appraisal as a suitable platform for disposable electronic strip-tests for assays in biological fluids requiring very low detection limits.

A plasma enhanced chemical vapor deposition process was proposed to functionalize the P3HT organic semiconductor surface of electrolyte gated organic field effect transistors with hydrophilic coatings bearing –COOH groups. Results demonstrate that the developed plasma process allows to functionalize the P3HT surfaces with carboxyl groups with negligible adverse effect on the bulk properties of P3HT as well as on EGOFET performances.

A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10^-3 cm^2 V^-1 s^-1 range and an on/off current ratio of 10^3. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids.

We report on the use of a polyanionic proton conductor, poly(acrylic acid), to gate a poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]-based organic field-effect transistor (OFET). A planar configuration of the OFET is evaluated, and the electrical performance and implementation on a flexible substrate are discussed.

The on–board quantification of exhaust emission from the internal combustion engines is of global concern in order to monitor and control release of toxic gaseous pollutants such as the oxides of nitrogen (NOx). This scenario calls for highly performing, cost–effective and long lasting gas sensors. In this regard, semiconducting metal oxides present the foremost choice of active materials for real–time detection of exhaust gases due to their low cost, good electrical properties, high sensitivity and stability at temperatures as high as >500°C [1]. In this work, we report on the synthesis, analytical characterization, and surface modification of metal oxide nanoparticles (ZnO–, ZrOx, InOx- NPs) for their potential application as semiconductor gas sensors. ZnO is a promising material and one of the earliest oxides studied for gas adsorption [2]. However, owing to its high working temperature and limited selectivity, ZnO did not achieve commercial success. ZrOx and InOx nanomaterials are well known active components of NOx sensors, which have shown some performance limitations –either in selectivity or in response intensity and kinetics-. To overcome these limitations, in recent years semiconductor metal oxides (MO) are being frequently modified by selected inclusions of transition metal nanoparticles, bringing their own surface reactivity characteristics to the hybrid catalyst-MO system [3]. In the present study, MO–NPs are prepared via simple and economical sol–gel methods. The surface of MO–NPs is subsequently modified by electro–chemical decoration of nanoscale gold (nano–Au), performed under surfactant stabilization conditions. Since Au nanoparticles exhibit pronounced selectivity toward NOx gases [4], the nano–Au/MO–NPs hybrids are believed to enhance the sensing properties of MO–NPs such as the selectivity and long–term stability of the nanomaterial. Both the pristine MO–NPs and the composite nano–Au/MO–NPs are calcined at temperatures >500°C to induce stability at the usual operating temperature of gas-sensing experiments and the effect of calcination on nanostructure and morphology is systematically studied. The as–prepared and the calcined nanomaterials are characterized by transmission electron microscopy, scanning electron microscopy, X–ray photoelectron spectroscopy, and X–ray diffraction techniques. The results demonstrate that these nanomaterials are highly stable and even ultrafine gold nanophases retain their morphology and surface chemical speciation upon annealing. The experimental evidences support further application of these composite nano–Au/MO–NPs as active elements in semiconductor NOx gas sensors.

Low density lipoprotein self-assembled layers on gold support, proposed as model for oxidation studies, were subjected to oxidation processes using different oxidative agents: 2,20-Azobis(2methylpropionamidine)dihydrochloride, atmospheric oxygen, and metal-induced oxidation. The freshly prepared and the oxidized layers were characterized by X ray photoelectron spectroscopy (XPS), Fourier-Transformed infrared spectroscopy, and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-ToF) mass spectrometry to discriminate the effects of oxidative reagents. Data obtained from FTIR and MALDI spectra proved the lipoperoxide formation subsequent to reactive oxygen species attack and the opportunity to use the model to discriminate between oxidation toxicity.

Organic field-effect transistors including a functional bio-recognition interlayer, sandwiched between the dielectric and the organic semiconductor layers, have been recently proposed as ultrasensitive label-free biosensors capable to detect target molecule in the low pM concentration range. The morphology and the structure of the stacked bilayer formed by the protein bio-interlayer and the overlying organic semiconductor is here investigated for different protein deposition methods. X-ray scattering techniques and scanning electron microscopy allow to gather key relevant information on the interface structure and to assess target analyte molecules capability to percolate through the semiconducting layer reaching the protein deposit lying underneath. Correlations between the structural and morphological data and the device analytical performances are established allowing to gather relevant details on the sensing mechanism and further improving sensor performances, in particular in terms of sensitivity and selectivity.

Nowadays we have no doubt that surfaces exist, we recognize that their physicochemical properties are different from those of the bulk, we exploit this fact for a variety of fundamental studies and applications, and surface science is a mature and distinct discipline. It was not so in the past, when surfaces were a matter of lively debate among ancient philosophers. The thoughts of Plato, Aristotle, and Posidonius in favour or against the existence and definition of surfaces, and the historical excursus of the surface concept during the centuries has been well reviewed (Paparazzo E. (2003) Surfaces—lost and found, Nature 3:351–353). The claim of Wolfgang Pauli that the bulk of a bodywas created byGod while the devil invented the surface is further proof of the concern that scientists had and still have about surfaces. Perversely, the mixture of attraction and distrust surfaces exerted on researchers stimulated the development of instruments and strategies able to guarantee scientists full control of them. Once scientists became confident of dominating surface chemistry and physics, they went as far as issuing the challenge of fabricating and manipulating nano-sized materials, for which the surface effects are enormously amplified. Nowadays functionalization of nano-patterned or nanostructured surfaces and surface engineering approaches are mature technology and are formidable tools in a plethora of applications in different fields. In analytical chemistry, surface architecture is designed and developed mainly for use in applications in which selectivity is needed, e.g. separation science, recognition assays, capture/release of drugs, sensors. Several approaches are available for building a suitable molecular recognition interface, the choice being related to the principles of transduction, and the nature of the receptor and the analyte. Generally speaking, a crucial point is immobilization of the receptor, which can be accomplished by adsorption, physical entrapment, covalent binding, or use of a chemical and/or biochemical “capture system”. These approaches may take advantage of a variety of surfaceengineering techniques, for example self-assembly of monolayers (SAM), Langmuir–Blodgett (LB), Langmuir–Schafer (LS), layer by layer assembly (LBL), surface functionalization, molecular imprinting in polymers (MIP), nanoscale patterning, and chemical or physical vapour deposition. This issue covers a broad range of examples of surface architecture designed and realized mainly for fabrication of highly selective and highly sensitive sensing devices able to meet today’s challenges in analyte detection and discrimination. A series of reviews present the state of the art spanning from functionalization of nano-structured materials for DNA detection to construction of protein layered architecture for recognition of biomolecules; from viable cell immobilization to molecular template integration for detection of analytes of medical, toxicological, and environmental interest; from interlocked surface-attached architecture for ion recognition to the many configurations of active components in organic field-effect transistors for detection of organic and/or inorganic species of biological interest. Reviews critically discuss crucial issues which affect more or less all classes of sensors and in some cases still limit their performances and/or prevent their use in real life; important aspects of these are immobilization of the recognition element, which should preserve its chemical and/or biological functionality, and the integration between recognition element and transducer. Moreover, insights are provided on problems related to miniaturization, stability, reliability, and lowcost production, and future perspectives for each class of sensing device are emphasized. We thank the authors for their valuable and timely contribution

The control of pollutants emission from internal combustion engines is a worldwide issue, in the automotive field. The roadmap for the reduction of vehicle emission limits is driving the academic and industrial interest towards the development of innovative systems integrating novel detection elements and fast feedback circuits and actuators. Based on a tighter control over emissions, and starting from 2014, Euro 6 standards are expected to improve the environmental compatibility of a new generation of vehicles in Europe. This scenario calls for a significant improvement of the sensors technologies for the detection of the main pollutants related to the automotive field, including nitrogen oxides (NOx). In this work, we report on the synthesis and analytical characterization of hybrid nanocomposites containing gold nanoparticles (Au-NPs) and metal oxide nanostructures (MO-NPs, such as zirconium oxide, indium oxide, oxide mixtures, etc.). These species are promising for real-time detection of low levels of NOx species, owing to their low cost, high sensitivity and availability under a variety of stoichiometric and mixing ratios, showing different gas sensing characteristics [1- 2]. Different MO-NPs and mixed MO-NP systems were prepared using a simple but efficient sol-gel method. Subsequently, the nano-oxides were electrodecorated by Au-NPs. Since Au nanophases exhibit pronounced selectivity toward NOx gases [3], the resulting hybrid nanocomposites are expected to improve the nanomaterial sensing performance. All the nanomaterials were characterized using FTIR, XPS, XRD, TEM, and SEM techniques. Experimental evidences support further application of these NPs as active elements in novel NOx sensors.

Organic thin film transistor (OTFT) technology can be implemented to develop cost-effective and label-free bio-affinity sensor chips, having a field-effect transport directly coupled to a bio-sensing process, useful to high-throughput testing and point-of-care applications. Biological recognition elements such as antibodies or other proteins can be integrated in OTFT devices to confer specificity. In this study the use of lipid bilayers as support for biomolecules immobilization is investigated. Preliminary results in terms of electrical resistance and capacitance of the lipid bilayers are presented.

A simple and time-saving wet method to endow the surface of organic semiconductor films with carboxyl functional groups is presented. A thin layer of poly(acrylic acid) (pAA) is spin-coated directly on the electronic channel of an electrolyte-gated organic FET (EGOFET) device and cross-linked by UV exposure without the need for any photo-initiator. The carboxyl functionalities are used to anchor phospholipid bilayers through the reaction with the amino-groups of phosphatidyl-ethanolamine (PE). By loading the membranes with phospholipids carrying specific functionalities, such a platform can be easily implemented with recognition elements. Here the case of biotinylated phospholipids that allow selective streptavidin electronic detection is described. The surface morphology and chemical composition are monitored using SEM and XPS, respectively, during the whole process of bio-functionalization. The electronic and sensing performance level of the EGOFET biosensing platform is also evaluated. Selective analyte (streptavidin) detection in the low pM range is achieved, this being orders of magnitude lower than the performance level obtained by the well assessed surface plasmon resonance assay reaching the nM level, at most.

The detailed action mechanism of volatile general anesthetics is still unknown despite their effect has been clinically exploited for more than a century. Long ago it was also assessed that the potency of an anesthetic molecule well correlates with its lipophilicity and phospholipids were eventually identified as mediators. As yet,the direct effect of volatile anesthetics at physiological relevant concentrations on membranes is still under scrutiny. Organic field-effect transistors(OFETs)integrating a phospholipid (PL) functional biointer-layer(FBI)are here proposed for the electronic detection of archetypal volatile anesthetic molecules such as diethylether and halothane. This technology allows to directly interface a PL layer to an electronic transistor channel,and directly probe subtle changes occurring in the bio-layer. Repeatable responses of PLFBI-OFET to anesthetics are produced in a concentration range that reaches few percent,namely the clinically relevant regime. The PLFBI-OFET is also shown to deliver a comparably weaker response to a non-anesthetic volatile molecule such as acetone

La presente invenzione riguarda dispositivi sensori analiti gassosi comprendenti transistor a film sottile organico e, in particolare, sensori in grado di effettuare la discriminazione enantiomerica di analiti gassosi. I film sottili organici sono caratterizzati dal fatto di comprendere un composto di formula (I).

Transistore comprendente almeno uno strato conduttivo (4), almeno uno strato dielettrico di gate (3) e almeno un film semiconduttore (1) depositato su uno strato di molecola recettore (2) precedentemente depositato o collegato in modo covalente alla superficie del gate dielettrico (3). Detto strato di materiale biologico è costituito da strati singoli o doppi di fosfolipidi, strati costituiti da proteine ​​quali recettori, anticorpi, canali ionici ed enzimi, singoli o doppi strati di fosfolipidi con inclusione o ancoraggio di proteine ​​quali: recettori, anticorpi, ionici canali ed enzimi, strati fatti di sonde oligonucleotidiche (DNA, RNA, PNA), strati fatti di cellule o virus, strati fatti di recettori sintetici per esempio molecole o macromolecole simili ai recettori biologici per proprietà, reattività o aspetti sterici.

L'invenzione consiste in un transistore “electrolyte gated” che integra uno strato di elementi biologici di riconoscimento in grado di rivelare selettivamente il loro ligando di affinità presente ad una concentrazione nel range dello zepto-molare (10-12 M).

La struttura del dispositivo proposta nella domanda di brevetto no. EP 16207596.4 è stata migliorata per rendere il dispostivo piu’ stabile.

Si tratta di un sensore a transistore, cos’ come del suo array, capace di rivelare, in modo affidabile, selettivo e label-free fino ad una singola molecola di DNA così come di anticorpi e peptidi. noltre il semiconduttore usato è un composito nanostrutturato a base di un polimero semiconduttore, facile da preparare, scalabile ed economico, è anche particolarmente stabile quando impiegato in diretto contatto con l’acqua.

Nanoparticles having a core formed of a metal selected from Ag, Cu, Sn and Zn and a shell formed of a plurality of molecules of quaternary ammonium compounds NR 1 R 2 R 3 R 4 + X - , where X is selected from Cl, Br and I and where NR 1 R 2 R 3 R 4 + is a quaternary ammonium compound wherein at least one R is different from the others and is an alkyl chain, linear or functionalised or provided with branches or aromatic lateral groups with length preferably between 8 and 18 atoms of carbon.

In nanoparticles having formula (Me)(NR 4 + X - ) n wherein Me is the metal core selected from Ag, Cu, Sn and Zn; (NR 4 + X - ) is the shell, where X is selected from Cl, Br and I, and R is an alkyl chain C 4 -C 12 , the length of the alkyl chain is chosen to control the release speed of metal ions from the core; several types of nanoparticles all with equal chains in the same particle can form a composition for antimicrobial applications to fabrics and the like.

Transistor comprising at least one conductive layer (4), at least one gate dielectric layer (3) and at least one semiconducting film (1) deposited on top of a receptor molecule layer (2) previously deposited or covalently linked to the surface of the gate dielectric (3). Said layer of biological material is constituted by single or double layers of phospholipids, layers made of proteins such as receptors, antibodies, ionic channels and enzymes, single or double layers of phospholipids with inclusion or anchoring of proteins such as: receptors, antibodies, ionic channels and enzymes, layers made of oligonucleotide (DNA, RNA, PNA) probes, layers made of cells or viruses, layers made of synthetic receptors for example molecules or macromolecules similar to biological receptors for properties, reactivity or steric aspects.

Transistor comprising at least one conductive layer, at least one dielectric layer and at least one thin organic semiconductor film and characterized by at least one layer of biological material deposited directly on the surface of the dielectric. Said layer of biological material is constituted by single or double layers of phospholipids, layers made of proteins such as receptors, antibodies, ionic channels and enzymes, single or double layers of phospholipids with inclusion or anchoring of proteins such as: receptors, antibodies, ionic channels and enzymes, layers made of oligonucleotide (DNA, RNA, PNA) probes, layers made of cells or viruses, layers made of synthetic receptors for example molecules or macromolecules similar to biological receptors for properties, reactivity or steric aspects.

This invention pertains to gaseous analytes sensor devices comprising organic thin film transistor and, in particular sensors able to perform the enantiomeric discrimination of gaseous analytes. The organic thin films are characterized by comprising a compound of formula (I).