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Metal oxide thin films show promising resistive switching properties, making them materials of reference for the development of memristive devices. TiO2 is probably one of the most studied materials and is being synthesized using various techniques, each of them having specific optimizable characteristics. In this paper, we report on an innovative approach by combining the sol–gel and the pulsed microplasma cluster source (PMCS) methods, exploiting the low temperature and low cost of the former process and precise control over nanocristallinity of the latter. We show that this approach overcomes the reported limitations that each technique shows in fabricating memristive devices when independently used. A side-by-side comparison of the TiO2 thin films produced by the PMCS, sol–gel, and PMCS/sol–gel hybrid methods (HM) demonstrates an improvement of the memristive properties and a reduction of the electrical shorts in the TiO2 based devices.

Sol-gel derived multi-layer ZnO films were prepared by spin coating technique on soda-lime glass, silica, silicon and platinum substrates from an alcoholic solution of zinc acetate dihydrate and monoethanolamine at different synthetic conditions. The curing and annealing conditions for the ZnO films were adjusted based on the study performed on the ZnO xerogel powders. Structural and morphological features as well as the thermal behavior of the samples were investigated by complementary techniques including electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analyses, and X-ray diffraction analysis. According to the electrical measurements performed on ZnO thin films sandwiched between Pt/Ti/SiO 2 substrate and Ag dishes as a top electrode, the selected fabrication conditions were suitable for fulfilling the requirements of active resistive layers for the development of memristive devices.

In this paper a novel approach is presented to prepare flexible and transparent conducting films, whose components can be separated and recovered via a recycling process. The fabrication method is based on low power sputtering of ultrathin gold layers on sodium alginate free-standing films. The resulting foils are thin, easy to handle, and shape, while showing good conductive properties. In particular, they show excellent resistance to mechanical stress, like bending or rubbing, and are highly stable in ambient atmosphere over several months. Therefore they may represent a very promising candidate to be employed in green electronics, thanks to the reduced energy consumption required for their fabrication, the absence of toxic components or chemicals that are derived from oil, and the possibility to disassemble the devices at the end of their life in environmentally friendly conditions.

We report an optofluidic ring resonator sensor based on liquid-core hybrid silicon-polymer waveguides. The device features a planar layout that combines optical and fluidic functions on the same platform. A high quality factor of $1.44\, \times \, 10^{4}$ is achieved. The device resonant wavelength shift has been measured as a function of the water-core temperature, obtaining a temperature sensitivity of 0.0633 nm/°C. Based on the thermo-optic effect of water, this corresponds to a bulk refractive index (RI) sensitivity of $\sim 700$ nm per RI unit (RIU), resulting in the RI limit of detection of $\sim 1.57\times 10^{\mathrm {-6}}$ RIU. The planar architecture combined with an optofluidic design concept holds the promise of high functionality and compactness toward a complete on-chip integrated sensing system.

Sol-gel derived TiO2 thin films were prepared by spin- coating from an alcoholic solution of titanium isopropoxide. With the aim to develop titania layers suitable for memristive devices, the films were deposited onto test structures based on fused silica quartz substrates patterned with a Ti (5nm)/Pt (50nm) layer. The reported fabrication protocol is suitable for the development of a memristive device. Optical, structural, and morphological features of the samples were investigated with complementary techniques, such as scanning electron microscopy (SEM), prism coupling m-line and micro-Raman spectroscopy as well as transmittance and profilometry measurements. The quality of the surface of the obtained films was evaluated by SEM technique, and the morphology of samples deposited with different fabrication protocols was investigated. Additionally, a computer code for the refractive index and thickness estimation from the transmittance spectra was developed by unconstrained optimization procedure. The results of simulation were in good agreement with the experimental data obtained by m-line measurements. Moreover, the porosity of a specific set of test unannealed films has been estimated. TiO2 films exhibit thickness of tens of nm, and micro-Raman spectroscopy in conjunction with SEM indicate the presence of anatase phase after thermal annealing at 400 °C. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

This work presents the advanced version of novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing chip. The new version of the tactile sensing chip presented here comprises of a 4 x 4 array of POSFET touch sensing devices and integrated interface electronics (i.e. multiplexers, high compliance current sinks and voltage output buffers). The chip also includes four temperature diodes for the measurement of contact temperature. Various components on the chip have been characterized systematically and the overall operation of the tactile sensing system has been evaluated. With new design the POSFET devices have improved performance (i.e. linear response in the dynamic contact forces range of 0.01–3N and sensitivity (without amplification) of 102.4 mV/N), which is more than twice the performance of their previous implementations. The integrated interface electronics result in reduced interconnections which otherwise would be needed to connect the POSFET array with off-chip interface electronic circuitry. This research paves the way for CMOS (Complementary Metal Oxide Semiconductor) implementation of full on-chip tactile sensing systems based on POSFETs.

An unconventional approach to impedance microbiology for Escherichia coli detection is under investigation. The detection principle of solution conductivity variation is based on intracellular content escape resulting from bacteriophage cell lysis. Bare electrodes on-chip included in a PDMS chamber were applied to the impedance measurements. Proofs of principle experiments were performed. In parallel, paramagnetic nano-beads were functionalised with selective phages for sample magnetic concentration and future methods integration. The system potential detection limit is about 10 CFU/chamber and provides the means for selective detection of viable cells. The methods integration could provide cost–effective results in less than 1 hour.

This work reports the development and the characterization of a microthermoelectric generator (μTEG) based on planar technology using electrochemically deposited constantan and copper thermocouples on a micro machined silicon substrate with a SiO2/Si3N4/SiO2 thermally insulating membrane to create a thermal gradient. The μTEG has been designed and optimized by finite element simulation in order to exploit the different thermal conductivity of silicon and membrane in order to obtain the maximum temperature difference on the planar surface between the hot and cold junctions of the thermocouples. The temperature difference was dependent on the nitrogen (N2) flow velocity applied to the upper part of the device. The fabricated thermoelectric generator presented maximum output voltage and power of 118 mV/cm2 and of 1.1 μW/cm2, respectively, for a device with 180 thermocouples, 3 kΩ of internal resistance, and under a N2 flow velocity of 6 m/s. The maximum efficiency (performance) was 2 × 10−3 μW/cm2 K2.

We report the development of sol-gel derived TiO2 thin films with adjustable and defined properties suitable for memristive cell fabrication. Memristive cells were developed by the sol-gel deposition of titania onto SiO2/Ti/Pt engineered electrodes via spin coating, followed by diverse curing and annealing procedures. The influence of the processing conditions and the sol's chemical composition on the film properties, and therefore on the memristive response, was studied by micro-Raman and transmission spectroscopies, profilometry, ellipsometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and X-ray absorption and diffraction spectroscopies (XAS and XRD). A memristive response was acquired from a number of these cells, revealing a dependence of the electrical behavior on minor changes in the TiO2 structure, electroforming parameters, and architecture. Thus, these properties provide a handle for fine-tuning electrical performance.

This work describes the development and testing of a microfabricated sensor for rapid cell growth monitoring, especially focused on yeast quality assessment for wine applications. The device consists of a NMOS ISFET sensor with Si(3)N(4) gate, able to indirectly monitor extracellular metabolism through pH variation of the medium, and a solid-state reference electrode implemented with PVC membranes doped with lipophilic salts (tetrabutylammonium-tetrabutylborate (TBA-TBB) and Potassium tetrakis(4-chlorphenyl)borate (KTClpB)). The use of a solid state reference electrode enables the implementation of a large number of cell assays in parallel, without the need of external conventional reference electrodes. Microbial growth testing has been performed both in standard culture conditions and on chip at different concentrations of ethanol in order to carry out a commonly used screening of wine yeast strains. Cell growth tests can be performed in few hours, providing a fast, sensitive and low cost analysis with respect to the conventional procedures.

This paper presents the design, fabrication and evaluation of the new version of POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) touch sensing device based tactile sensing chip. Implemented using CMOS (Complementary Metal Oxide Semiconductor) technology, the chip consists of POSFET device and the integrated bias and signal conditioning circuitry. In particular, a high compliance current sink and an output buffer have been integrated to respectively bias the POSFET device and to decouple the sensor from chip output. The performance of tactile sensing chip has been evaluated in the dynamic contact forces range of 0.01–3 N and the sensitivity of POSFET devices (without amplification) is 102.4 mV/N.

Micro/nanostructures of single-crystal Si, in the form of wires and ribbons, are promising building blocks for realizing high performance nano- to macro scale field-effect transistors (FETs). This work presents the method to fabricate single-crystal Si wires and ribbons from silicon-on-insulator (SOI) wafers using ''top-down'' fabrication strategy and transfer the same to ultra flexible substrates. Si wires with lengths ranging from 30 to 5000@mm and widths ranging from 4 to 50@mm have been fabricated. The parallel aligned wires are then successfully transferred, first to a flexible transfer substrates (PDMS) and then to the final receiver substrate (polyimide). Finally, the bending of Si wires has been investigated by bending them up to 220 degrees without breaking. Such a high bending of wires demonstrate the possibility of obtaining ultra flexible integrated electronics on flexible substrates.

This work presents an improved platform for single-site electroporation and controlled transfectants delivery. The device consists of a gold microelectrode array (MEA) with integrated microfluidics and nanostructured titanium dioxide (ns-TiO2) functionalized electrodes for the improvement of cell adhesion. Human cervical cancer cells (HeLa) have been successfully cultivated on chip surface using traditional protocols. The system has been previously tested by electroporating HeLa cells with Lucifer Yellow (LY) and then, in order to validate the approach and cell viability, with plasmid for the enhanced expression of Green Fluorescence Protein (pEGFP-N1) delivered through microchannels.

This work presents fabrication and evaluation of novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing chip. In the newer version presented here, the tactile sensing chip has been fabricated using CMOS (Complementary Metal Oxide Semiconductor) technology. The chip consists of 4 x 4 POSFET touch sensing devices (or taxels) and both, the individual taxels and the array are designed to match spatio–temporal performance of the human fingertips. To detect contact events, the taxels utilize the contact forces induced change in the polarization level of piezoelectric polymer (and hence change in the induced channel current of MOS). The POSFET device on the chip have linear response in the tested dynamic contact forces range of 0.01–3N and the sensitivity (without amplification) is 102.4mV/N.

This paper presents the research on tactile sensing system on chip. The tactile sensing chips comprise of 5 × 5 array of Piezoelectric Oxide Semiconductor Field Effect Transistor (POSFET) devices and temperature sensors. The POSFET devices are obtained by spin coating piezoelectric polymer, poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), films directly on to the gate area of Metal Oxide Semiconductor (MOS) transistors. The tactile sensing chips are able to measure dynamic contact forces and temperatures. The readout and the data acquisition system to acquire the tactile signals are also presented. The chips have been extensively tested over wide range of dynamic contact forces and temperatures and the experimental results are presented. The paper also reports the research on tactile sensing chips with POSFET array and the integrated electronics.

In this study, we present a microdevice coated with titanium dioxide for cells and particles separation and handling. The microsystem consists of a pair of planar interdigitated gold micro-electrode arrays on a quartz substrate able to generate a traveling electric completed with a microfabricated three-dimensional glass structure for cell confinement. Dielectrophoretic forces were exploited for both vertical and lateral cell motions. In order to provide a biocompatible passivation layer to the electrodes a highly biocompatible nanostructured titanium dioxide film was deposited by supersonic cluster beam deposition (SCBD) on the electrode array. The dielectrophoretic effects of the chip were initially tested using polystyrene beads. To test the biocompatibility and capability of dielectrophoretic cell movement of the device, four cell lines (NIH3T3, SH-SY5Y, MDCK, and PC12) were used. Separation of beads from SH-SY5Y cells was also obtained.

This work presents the design, fabrication and characterization of a Si-based microseparation module for liquid chromatography (LC), targeted for agrofood applications and in particular for wine quality monitoring. The microsystem chip is a Silicon/Pyrex structure realized by anodic bonding. The basic Si-chip modules are an open tubular microcolumn with inlet/outlet for fluidic connections, a platinum heater and a Pt three-electrode amperometric sensor. Analytical calculations and finite element analysis have been performed to optimize the microcolumn design. Microchannels and inlet/outlet have been fabricated by deep reactive ion etching (DRIE) and tetra methyl ammonium hydroxide (TMAH) wet etching, respectively. The column has been functionalized with n-octyltriethoxysilane (C8-TEOS). Preliminary characterization tests of the microcolumn have been performed by evaluating the capability of the system to retain test solutions of acetic acid.

Herein, we report a memristive response from Pt/TiO2/Ta2O5/Pt stack thin films with low SET and RESET voltages, and resistance ratio of 103. For the first time, Pt/TiO2/Ta2O5 stack thin films were produced by sol-gel procedure. The morphology and elemental composition of Pt/TiO2/Ta2O5 stacks were studied by a set of complementary techniques, including scanning electron microscopy (SEM), field-emission electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the material was estimated from the transmittance spectrum by Pointwise Unconstrained Optimization Approach (PUMA). Keywords: Memristive response, Tantalum pentoxide, Titanium dioxide, Sol-gel, Thin films

This work presents the realization of a Si-based miniaturised device for liquid chromatography (LC), targeted for agrofood applications and in particular for wine quality monitoring. The main modules of the system are: (1) a Si-based separation column, functionalized by n-octyltriethoxysilane (C8-TEOS), with inlet/outlet for fluidic connections; (2) a three-microelectrode voltammetric sensor. The system has been properly packaged and the capability of the sensing module to detect acetic acid concentration changes has been verified.

In this paper, we present a new type of rf MEMS switch with low actuation voltage and high isolation, for high rf power and reliability applications in telecommunication. ‘Symmetric toggle switch’ (STS) is based on push–pull mechanism and utilizes torsion springs and levers, placed symmetrically and transverse to CPW line. The switches designed for 8–14 GHz applications have analytically calculated and FEM simulated actuation voltages in the range of 8–10 V. The simulated insertion loss and isolation for the devices are 0.25 and 35 dB, respectively, at 10 GHz. The fabrication process and preliminary experimental results are also presented.

Herein, we developed a series of Pt/TiO 2 /Pt/Ti/SiO 2 resistive switching materials with a variation in chemical composition of TiO 2 in an attempt to evaluate the parameters affecting the memristive switching behavior and, therefore, to optimize and control it. Different chemical compositions of TiO 2 were obtained by annealing the films at 400 °C for 1 hour in diverse atmospheric conditions, such as air, vacuum and oxygen environments. The elemental composition of the produced samples was analyzed by X-ray photoelectron spectroscopy (XPS), revealing the different stoichiometric ratio of Ti/O and doping/contamination with silicon, carbon, and nitrogen depending on the annealing conditions. The preliminary I–V curves were acquired with Pt dish or wire, serving as a top electrode. The results showed a superior stability, durability and reproducibility of the resistive switch behavior observed in the samples containing oxidized silicon impurities. In addition to the electrical studies, the evolution of Pt dish top electrode was monitored by optical microscopy and scanning electron microscopy (SEM), revealing mechanical and electrochemical damage of the electrode during the electroforming step

We propose a multi-technique approach based on in-vacuum synthesis of metal oxides to optimize the memristive properties of devices that use a metal oxide thin film as insulating layer. Pulsed Microplasma Cluster Source (PMCS) is based on supersonic beams seeded by clusters of the metal oxide. Nanocrystalline TiO{sub 2} thin films can be grown at room temperature, controlling the oxide stoichiometry from titanium metal up to a significant oxygen excess. Pulsed Electron beam Deposition (PED) is suitable to grow crystalline thin films on large areas, a step towards producing device arrays with controlled morphology and stoichiometry. Atomic Layer Deposition (ALD) is a powerful technique to grow materials layer-by-layer, finely controlling the chemical and structural properties of the film up to thickness of 50-80 nm. We will present a few examples of metal-insulator-metal structures showing a pinched hysteresis loop in their current-voltage characteristic. The structure, stoichiometry and morphology of the metal oxide layer, either aluminum oxide or titanium dioxide, is investigated by means of scanning electron microscopy (SEM) and by Raman scattering.

This work reports the development of a micro thermoelectric generator based on planar technology using electrochemical deposited process with constantan and copper thermocouples on a micromachined silicon substrate. This configuration was selected because it can be manufactured into large area, flexible substrates, and the selected materials can be deposited with low-cost process. Efficiency of the module was investigated in different working condition, showing a maximum generated potential of 118 V/cm2 and a power of 1.1 μW/cm2. Constantan alloy electrodeposited at different deposition potential was characterized by Energy Dispersive X-ray Spectroscopy (EDX) and Scattering Electronic Spectroscopy (SEM) to observe the morphology and composition of the films.

This study describes the design, simulation, and micro fabrication of a micro thermoelectric generator (μTEG) based on planar technology using constantan (CuNi) and copper (Cu) thermocouples deposited electrochemically (ECD) on silicon substrate. The present thin film technology can be manufactured into large area and also on flexible substrate with low cost of production and can be used to exploit waste heat from equipments or hot surfaces in general. In the current implementation, the silicon structure has been designed and optimized with analytical models and FE simulations in order to exploit the different thermal conductivity of silicon and air gaps to produce the maximum temperature difference on a planar surface. The results showed that a temperature difference of 10K across the structure creates a temperature difference of 5.3K on the thermocouples, thus providing an efficiency of thermal distribution up to 55%, depending on the heat convection at the surface. Efficiency of module has been experimentally tested under different working condition, showing the dependence of module output on the external heat exchange (natural and forced convection). Maximum generated potential at 6m/s airflow is 5.7V/m 2 K and thermoelectric efficiency is 1.9μW K -2 m -2 .

This work presents the advanced version of novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing chip. The tactile sensing chip in the new version, presented here, has been fabricated using CMOS (Complementary Metal Oxide Semiconductor) technology. The chip consists of 4 × 4 POSFET touch sensing devices, four temperature diodes, and the electronic circuitry comprising of multiplexers, current mirrors, high compliance current sinks and voltage output buffers. The on chip POSFET devices have linear response in the tested dynamic contact forces range of 0.01-3N and the sensitivity (without amplification) is 102.4 mV/N.

This work presents research towards obtaining ultra-thin silicon chips (flex-chips) on flexible foils through post-processing steps. The flex-chips are obtained by chemically thinning down the silicon and then transferring the chips to polyimide foils. The transfer printing approach that has thus far been used to transfer quasi 1-D structures such as wires and ribbons, has been adapted in this work to transfer various large sized (width of chips ranging from 4.5mm to 1.5cm and the length ranging from 8mm to 3.6cm) and ultra-thin (thickness ≈ 15μm) chips. The flex-chips contain passive devices, whose resistances do not show any appreciable change on bending, at least in the testing range of radius of curvature 9mm and above. The distinct advantages of the work presented here are attaining bendability through postprocessing of chips, low-cost of fabrication, and east transferring of chips to the flexible substrates without using conventional and sophisticated equipment such as pick-an-place set up.

In this work the effect of air plasmas on wettability of Polydimethylsiloxane (PDMS) and polyethylene terephthalate (PET) was studied. These polymers are widely used materials in the fabrication of microfluidic devices. The microfluidic system fabricated from native PET and PDMS requires active pumping mechanism, due to a low hydrophilic surface behavior. To render hydrophilic and increase the capillary flow into the device, plasma treatments can be used. Air plasma treatment is an interesting technology for microfluidic fields due to simplicity of use and low cost. This study describes the effect of the working plasma pressure on wettability of polymers. The polymers were treated by RF plasma and the wettability was studied by means of sessile contact angle. The results established that the air plasma can increase the wettability of both polymers. Moreover we demonstrated that by optimizing the working pressure a superhydrophilic surface (with a contact angle less than 5°) can be obtained. The findings suggest that air plasma treatments are a suitable technology to enhance polymers surface wetting performance for microfluidic devices.

In this work, a compact low-cost system designed to detect low amounts of proteins in biological fluids is presented. The system, based on time-gated fluorescence detection principle, is composed by a Single-Photon Avalanche Diode (SPAD) pixel array, a LED excitation light source and a micro-machined reaction chamber coupled to a microfluidic network. A dual-site binding strategy based on DNA aptamers is used for target protein recognition. The microreactor, composed of an array of microwells covered with a transparent membrane, is functionalized with a primary aptamer, while a fluorescent-tagged secondary aptamer is used for the detection. Preliminary measurements demonstrate the feasibility of fluorescence lifetime detection to discriminate between different fluorophores. The detection of human thrombin protein in 300nM concentration is reported as a biological proof of principle of the biosensor.

This work presents current research achievements on POSFET sensing arrays based tactile sensing system. The tactile sensing chips implement POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices arrays and temperature sensors. This work presents quantitative evaluation of the tactile sensing chip and a proposal for the electronic data acquisition system. Our goal is to integrate the POSFET arrays into the hands of humanoid robots.

In this work we present the development of a system intended for DNA label free detection, based on piezoresistive microcantilever arrays and dedicated readout ASIC. Detector design and microfabrication technologies have been optimised for detection sensitivity, providing an efficient direct electrical measurement of DNA hybridisation. Readout ASIC has been implemented using a 0.35µm CMOS technology to provide a high resolution and low noise readout of the sensors, by also providing the compensation of large offset in the detector response.

This paper presents the design, fabrication and evaluation of the new version of POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) touch sensing device based tactile sensing chip. Implemented using CMOS (Complementary Metal Oxide Semiconductor) technology, the chip consists of POSFET device and the integrated bias (a high compliance current sink) circuitry. The high compliance current sink provides the current I DS for the POSFET devices. The performance of tactile sensing chip has been evaluated in the dynamic contact forces range of 0.01–3 N and the sensitivity of POSFET devices (without amplification) is 102.4 mV/N.

This work focuses on the realization of three different micro-actuators that will be integrated in a lab-on-chip for bioaffinity assays. The aim is to create a microfluidic network to control the sample and reagent delivery as well as the washing cycles for a complete analysis. The three micropumps have different working principles (electromagnetic, electrolytic and peristaltic actuation methods), but they share the same fabrication process. The reason for adopting three different actuation modes is mainly related to the different functionalities that have to be managed at microfluidic level. In particular the electrolytic one-shot micropump will be used for sample and reagents delivery, while the peristaltic and the electromagnetic micropumps are both good candidates for the washing cycles.

The present work is aimed at the design and fabrication of microfluidic devices for pharmacological in-vitro tests on cells as a tool for individuating the concentration range in which the drug effectiveness is guaranteed, with particular attention to anti-osteoporotic therapies with strontium ranelate. The microsystem consists of a microchannels network for the delivery and mixing of chemical species, designed to provide a controlled drug concentration to each cell culture [1]. The design and the optimization of the microfluidic network were carried out by means of both analytical and computational approaches. Besides, micromixers and wells modules were modeled, fabricated and tested separately. A prototype of the complete device has been produced and further experimental tests will be performed.

Nowadays, there is a great interest in developing microdevices able to perform in-vitro cell assays for high throughput drug screening. In this work, we propose two modules that could be integrated in a single platform: a gold microelectrode array (MEA) for single-site cell transfection and two interdigitated electrodes (IDEs) arrays for the controlled localization of cells and the delivery of bio-chemical species. The modules have been already realized, separately tested and both have demonstrated their feasibility. The final aim is to perform single-site drug delivery in a microfluidic structure where different bio chemical species could be addressed to different cell groups in specific areas of the chip. In perspective, an high level of integration can be obtained by combining the two miniaturized approaches through microfabrication techniques, resulting in a portable and high throughput system for fast and efficient in-vitro drug screening.

This work presents the realization of a MEMS-based miniaturized system for liquid chromatography focused on agrofood applications, and in particular on the detection of wine defects. The main modules of the systems are: i.) a Si-based separation column with inlet/outlet for fluidic connections; ii.) a three-microelectrode voltammetric sensor. Moreover, a Platinum heater has been realized on the back side of the chip containing the Si column in order to operate at temperatures greater than the room temperature. The realized device consists of a Silicon/Pyrex structure realised by anodic bonding. Microchannels and inlet/outlet have been fabricated by Deep Reactive Ion Etching (DRIE) and Tetra Methyl Ammonium Hydroxide (TMAH) wet etching respectively. The column has been functionalised with n-octyltriethoxysilane (C8-TEOS). A lift-off technique has been developed for realizing the Pt heater and the Pt microelectrodes on-chip. In order to separately characterize the main modules of the device, a package of the system has been realized following a modular approach; appropriate tubing and nanovolume connections have been used in order to minimize dead volumes. Then other packages approaches have been considered in order to minimize dead volumes and to avoid leakage issues. Preliminary characterization tests of the two main modules have been performed. The capability of the system to correctly retain and detect Acetic acid has been tested.

This work presents the design and simulations of an interdigitated micro-electrode array aimed to discriminate cancer cells, with potential applications in predictive oncology, diagnostics and anti-tumor drug research. The device has been designed and a technological fabrication process has been defined. The microsystem consists of a quartz substrate with gold electrodes and a microfabricated three-dimensional structure (glass/SU8) for cells confinement. The designed device consists of three separated part: two circular areas for confinement, detection and moving and a narrow channel between those areas for the transportation of the cells. The detection can be done by measuring the charge variations associated to the different membrane capacitances and conductivities of tumor and normal cells. Alternating electric field over the electrodes is used for moving the cells between the circular areas (Travelling Wave Dielectrophoresis TwDEP) as well as for levitating and trapping cells on the electrodes (positive-negative Dielectrophoresis p-nDEP). Analytical and Finite Elements simulations have been performed in order to verify the system reliability and to estimate the parameters in use, like operative frequency, voltage, expected velocity.

Development of robots capable of operating in unstructured environments or intended to substitute for man in hazardous or inaccessible environments, demands the implementation of sophisticated sensory capabilities, far beyond those available today. In this regard, the development of tactile sensors is one of the key technical challenges in advanced robotics and minimal access surgery. In this work we present arrays of 'taxels' (tactile elements) which will be placed on the distal phalange of the humanoid robot in our lab. We present two different designs and implementations. In the first one, microelectrode arrays(MEAs) of 32 elements, with 1 mm center to center distance, have been designed. The taxel is implemented by epoxy-adhering the sensing material (piezoelectric polymer film of PVDF-TrFE) on a microelectrode. Each taxel is intended to be used as an extended gate of an FET (external to the chip); the taxel collects the charge/voltage generated, as consequence of the applied stress, on the deposited piezoelectric polymer film (i.e. the extended gate itself). The second design and implementation integrates both the taxels array and the FET devices, on the same silicon die.

The feasibility of integrating the RF MEMS switches in space and wireless communication systems has generated tremendous interest in related fabrication, design and characterization methodologies [ 11. The applications make long term reliability of the devices a very pertinent issue, that involves both process and device characterization. The experimental methods to realize lifetime measurements and mechanical characterization of silicon MEMS switches are important tools to test the performance and reliability of the adopted microfabrication technology [2]. Both MEMS switches and dedicated test structures consisting of a series of suspended bridges have been designed to study the switch properties such as mechanical behavior and dependence of the actuation voltage on the bridge geometry. The composite bridge test structures have five suspended beams of different lengths with individually addressable actuation pads. A PC based experimental setup suitable for on-wafer long term electromechanical studies is developed around a manual probe station [3]-[4]. Our goal is to study the physical mechanisms related to the changes in device capacitance and actuation voltage due to dielectric charging and residual stress changes, as a function of the bias amplitude, polarity and pulse period.

In this paper we report the realization and characterization of low-loss, capacitive RF MEMS switches that utilize folded serpentine spring suspensions with large area actuation electrodes. The surface micromachined switches with 1.7 /spl mu/m thick electroplated gold beams are implemented in standard 50 ohm CPW configuration. The electromechanical characterization indicates the measured actuation voltages in the range of 8 - 15 volts. The RF measurements of devices give insertion loss of 0.24 dB and isolation better than 21 dB at 20 GHz.

In this work we present the development of system intended for DNA label free detection, based on piezoresistive microcantilever arrays and dedicated readout ASIC. Detector design and microfabrication technologies have been optimised for detection sensitivity, providing an efficient direct electrical measurement of DNA hybridisation. Three technological approaches were investigated and optimised by using analytical and finite element analysis: single crystal Si beams with implanted piezoresistors, SiO 2 cantilever with poly-Si piezoresistors and polymeric beams with gold strain gauges. According to results, the most performing technological approach is based on Silicon-On-Insulator (SOI) wafers, allowing the realisation of low thickness beams (340 nm silicon layer) with n-type resistors. Readout ASIC has been implemented in a separate chip using a 0.35 μm CMOS technology to provide a high resolution and low noise readout of the sensors, by also providing the compensation of large offset in the detector response.

This work presents an improved platform for single-site electroporation and controlled transfectants’ delivery. The device consists of a gold microelectrode array (MEA) with integrated microfluidics and nanostructured titanium dioxide (ns-TiO2) functionalized electrodes. Human cervical cancer cells (HeLa) have been successfully cultivated on chip surface. The system has been previously tested by electroporating them with Lucifer Yellow (LY) and then, in order to validate the approach and cell viability, with plasmids for the enhanced expression of Green Fluorescence Protein (pEGFP) delivered through microchannels.