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This paper reports on the development of a fluorescent label-free aptamer assay integrated in a lab-on-chip (LoC) system for the detection of Ochratoxin A (OTA). The detection system relies on the integration, on a single glass substrate, of an array of amorphous silicon photosensors and a long pass interferential filter. The aptamer assay, integrated into the microfluidic network, is an aptasensor having affinity versus OTA, selected as a case study. The fluorescent molecule is a "light switch" complex [Ru(phen)

We present an optoelectronic system-on-glass for on-chip quantitative detection of a specific analyte in a biological solution. The system includes an amorphous silicon photodetector and an optical waveguide, integrated on a single glass substrate. The solution under investigation is placed on a waveguide's region where a monochromatic light is travelling. Light coupling depends on the sample's optical properties. Two different waveguiding structures have been investigated: glass-made waveguides, obtained by the double ion-exchange method on the glass substrate, and SU-8 polymer waveguides, obtained by photolithography. Optical losses around 0.5 dB/cm at 532 nm were achieved. The analyte detection is performed by a thin-film amorphous silicon p/i/n junction, fabricated with microelectronic technologies. The tested photodiodes present shot noise currents of about 2 fA/sqrt(Hz) and responsivity around 500 mA/W at 532 nm. As proof of concept, hemoglobin was studied as analyte for a demonstration scenario, involving optical simulations interpolated with experimental data, resulting in a detection limit around 100 ppm, in line with well-established colorimetric methods currently on the market.

This work reports on the development of a large-area thin film heater for lab-on chip applications. The device is a chromium/aluminum/chromium stacked structure with a spiral shape fabricated on a $5\times 5\text{cm}^{2}$ glass substrate through microelectronic technologies. Its geometry has been designed and optimized by COMSOL Multiphysics in terms of pitch and line width to achieve a uniform temperature distribution. Measurements performed with a thermo-camera show temperature variation below 1.5°C over 5cm2 area in excellent agreement with numerical modeling. To our knowledge, this is the largest area with such temperature uniformity achieved with a single heater in lab-on-chip systems. This opens the route for large-area thermal treatments as multiple-well DNA amplification or cell culture.

An optoelectronic, integrated system-on-glass for on-chip detection of biomolecules is here presented. The system&rsquo, s working principle is based on the interaction, detected by a hydrogenated amorphous silicon photosensor, between a monochromatic light travelling in a SU-8 polymer optical waveguide and the biological solution under analysis. Optical simulations of the waveguide coupling to the thin-film photodiode with a specific design were carried out. A prototype was fabricated and characterized showing waveguide optical losses of about 0.6 dB/cm, a photodiode shot noise current of about 2.5 fA/Hz and responsivity of 495 mA/W at 532 nm. An electro-optical coupling test was performed on the fabricated device to validate the system. As proof of concept, hemoglobin was studied as analyte for a demonstration scenario, involving optical simulations interpolated with experimental data. The calculated detection limit of the proposed system for hemoglobin concentration in aqueous solution is around 100 ppm, in line with colorimetric methods currently on the market. These results show the effectiveness of the proposed system in biological detection applications and encourage further developments in implementing these kinds of devices in the biomedical field.

Tungsten oxide (WO3) thin-films fabricated on glass slides have been proven to generate lossy mode resonances (LMRs) in the visible region. Obtained devices were characterized in transmission by lateral incidence of light on the edge of glass slides. Resonances at both TE and TM polarizations were analyzed for different thicknesses and in different deposition conditions. Moreover, it was successfully proved that WO3 coated glass slides present a high sensitivity to refractive index, which opens the path to the application of this structure in the domain of optical sensors. This work was supported in part by the Spanish Agencia Estatal de Investigación (AEI) through project PID2019-106231RB-I00 and by Italian Ministry of University and Research (MIUR) through the University Research Project 2017 (prot. RG11715C8213BD81).

The study and quantification of the effects of the space environment on human body is a primary task for future manned deep space missions. The risk models for radiation exposures incurred by astronauts beyond low-Earth orbit, have different limitations due to the difficulty to have terrestrial parallels on which to base risk estimates. Indeed, no terrestrial sources fully reproduce the deep space energy spectrum and the multi directional flux of the cosmic radiation. In situ analysis would therefore be fundamental in order to enable reliable studies about the effects of the radiation environment on living organisms as well as to evaluate customized radiological countermeasures for astronauts. A micro-incubator suitable for cubesat missions for studying in situ the effects of the space environment on cellular cultures is presented. The device is based on lab-on-chip technology with integrated thin-film sensors and actuators for the active control of the environmental conditions of the cell culture and for the monitoring of its metabolic status. In particular, the device includes an incubation chamber connected to a microfluidic network for the supply of nutrients and/or pharmaceuticals. A second network is used for the distribution of carbon dioxide through a thin gas-permeable membrane. On-chip on-demand production of carbon dioxide can be eventually achieved from the pyrolysis of sodium bicarbonate stored in a separate reservoir with a dedicated thin film heater. The same network can be used to supply a controlled atmosphere from a pressurized tank. The on-chip hydrogenated amorphous silicon photodiodes are used to measure the light emitted by genetically-modified cell cultures that express a bio-luminescent behavior when subjected to given stress conditions. Accurate temperature control is achieved by means of additional on-chip thin-film diodes and a transparent indium-tin-oxide heater located beneath the incubation chamber. From technological point of view, the system relies on the combination of different thin- and thick-film fabrication technologies jointly used with the aim to achieve a compact, automated and low-power device that represents a viable solution for biological experiments aboard cubesat satellites.

This paper presents the analysis and development of an evanescent waveguide sensor system, based on a hydrogenated amorphous silicon (a-Si:H) photodiode and a double ion-exchanged waveguide diffused in a borosilicate BK7 glass substrate. The a-Si:H sensor is a p-doped/intrinsic/n-doped diode, with a metal top electrode and an indium tin oxide (ITO) transparent bottom contact. Simulations on the confinement of a monochromatic light in a channel waveguide and its coupling into a thin-film photodetector were performed using COMSOL Multiphysics. The system design considers a deep investigation on refractive index and thickness of the ITO layer, which are key parameters for the optical coupling optimization between the waveguide and the photodetector. The first prototype was made using standard microelectronics techniques: physical and chemical vapor deposition of the thin films of the structure, wet and dry etching of the different materials, and photolithography for the thin-film pattern definition. The electrooptical characterization of the fabricated device shows the effectiveness of the optical coupling and suggests its use for on-chip detection in lab-on-chip applications.

Self-supported ZSM-5 zeolite monolith foams (ZMFs) with different Si/Al ratios have been successfully prepared by hydrothermal synthesis with a polyurethane foam (PUF) template followed by calcination in air at 550 °C to harden. Cu or Mn have been introduced on preformed ZMF samples to obtain monolithic catalysts that have been fully characterized by morphological (XRD and SEM), textural (BET and pore size distribution), mechanical (compressive strength) and chemical (ICP-MS) analyses, and eventually tested in the Selective Catalytic Reduction of NO with NH3 in the temperature range 100–450 °C. The zeolite monolith foams are characterized by a well crystallized ZSM-5 structure, a BET surface area ca. 420 m2 g−1 and remarkable mechanical resistance even without any binder. Those structured catalysts show specific catalytic activity in line with powdered counterparts, but they can guarantee improved NO conversion due to the higher amount of catalyst per unit volume of reactor and to their superior mass transfer coefficients coupled to low internal diffusion limitations.

Innovative materials for the integration of aptamers in Lab-on-Chip systems are important for the development of miniaturized portable devices in the field of health-care and diagnostics. Herein we highlight a general method to tailor an aptamer sequence in two subunits that are randomly immobilized into a layer of polymer brushes grown on the internal surface of microfluidic channels, optically aligned with an array of amorphous silicon photosensors for the detection of fluorescence. Our approach relies on the use of split aptamer sequences maintaining their binding affinity to the target molecule. After binding the target molecule, the fragments, separately immobilized to the brush layer, form an assembled structure that in presence of a “light switching” complex [Ru(phen)2(dppz)]2+, emit a fluorescent signal detected by the photosensors positioned underneath. The fluorescent intensity is proportional to the concentration of the target molecule. As proof of principle, we selected fragments derived from an aptamer sequence with binding affinity towards ATP. Using this assay, a limit of detection down to 0.9 µM ATP has been achieved. The sensitivity is compared with an assay where the original aptamer sequence is used. The possibility to re-use both the aptamer assays for several times is demonstrated.

Xanthan and ?-carrageenan were used to prepare alkaline hydrogels to be used as electrolytes in aluminium air primary batteries. Two pasty gels were obtained starting from xanthan and KOH solutions (1 M and 8 M), while only the 8 M KOH solution permitted the formation of a stable, elastic and gumminess hydrogel with ?-carrageenan. Discharge tests, performed on three Al/air cells assembled with Al anodes, electrolyte gels and Pt based cathodes, evidenced that all hydrogels exhibited appreciable properties of Al ion conductivities, according to the following performance order: xanthan with KOH 1 M

In this paper we demonstrate the implementation of a micro-scaled integrated system with the aim to sort, estimate and monitor the biomass of living cancer cells suspended in a culture medium. For this purpose, a 3D microfluidic network is designed to route small volumes of biological samples to the testing sites and dielectric spectroscopy is chosen as investigation method. Comparative electrical analyses are guaranteed by the separation of sole medium and medium-cells mixture in two different areas of the chip. A polyimide-based micro-sieve, placed between two microfluidic channels, is used to perform cell filtering and sorting. Two couples of thin-film metal electrodes ensure the comparative dielectric measurements of the separated materials. Preliminary experiments were carried out in order to test the microfluidics and demonstrate its particle-separating capabilities. The first results prove the robustness of the chosen materials, the effectiveness of the micro-sieving device in terms of particle separation from a liquid solution and its successful integration in the microfluidics. The proposed system represents a promising step for the development of novel valid solutions in the field of micro-scaled integrated cell sorting, cell monitoring and cell counting for a wide range of applications, such as tissue engineering, tumor cells research and biological monitoring in space environment

This work presents an equivalent electrical circuit of hydrogenated amorphous silicon diodes. It is constituted by four diodes and two resistances. Each element is directly related to the physical behavior of the thin film structure and models the different conduction regimes of the device.Results show a very good fitting of the experimental current-voltage characteristic up to several hundreds of millivolts in both forward and reverse bias conditions and demonstrate the suitability of the developed model for designing the diode fabrication parameters for specific application.

We present a device based on amorphous silicon photosensors and glass-diffused waveguides to be used inside lab-on-chip systems, to perform biomolecular recognition by means of optical interaction with the analyte. A 150 × 300 µm2 p-i-n photosensor was fabricated on a 200 µm wide optical waveguide, by using standard thin film microelectronic techniques, such as: thermal diffusion processes, metals and dielectrics deposition, semiconductors growth, UV photolithography and wet-dry etching to define the structure geometries. The electro-optical characterization of the device shows the effectiveness of the optical coupling and suggests its use for on-chip detection in lab-on-chip applications.

The integration of systems for real-time monitoring of DNA amplification reactions is rather limited, because the heating system, the temperature control and the detection system are usually realized with separate modules. In this work, a lab-on-a-chip system for real-time monitoring of the multiple displacement amplification reaction (MDA) is presented. The amplification and detection unit consists of a system-on-glass (SoG) coupled to a microfluidic chip. The SoG includes thin film metallic resistors and amorphous silicon temperature sensors to control the temperature, as well as amorphous silicon photosensors and an interference filter for fluorescence detection on a single glass plate. The amplification reaction is carried out in the microfluidic chip made of cyclic olefin copolymer (COC). By using this setup, the multiple displacement amplification reaction can be monitored in real-time using the fluorophore [Ru(phen)2(dppz)]2+.

The detection of life markers is a high priority task in the exploration of the Solar System. Biochips performing in-situ multiplex immunoassays are a very promising approach alternative to gas chromatography coupled with mass spectrometry. As part of the PLEIADES project, we present the development of a chemiluminescence-based, highly integrated analytical platform for the detection of biomarkers outside of the Earth. The PLEIADES device goes beyond the current lab-on-chip approaches that still require bulky external instrumentation for their operation. It exploits an autonomous capillary force-driven microfluidic network, an array of thin-film hydrogenated amorphous silicon photosensors, and chemiluminescence bioassays to provide highly sensitive analyte detection in a very simple and compact configuration. Adenosine triphosphate was selected as the target life marker. Three bioassay formats have been developed, namely (a) a bioluminescence assay exploiting a luciferase mutant with enhanced thermal and pH stability and (b and c) binding assays exploiting antibodies or functional nucleic acids (aptamers) as biospecific recognition elements and peroxidase or DNAzymes as chemiluminescence reporters. Preliminary results, showing limits of detection in the nanomolar range, confirm the validity of the proposed approach.

This paper reports the development of a miniaturized lab-on-glass,suitable for the on-chip detection of living cell bioluminescence and their on-chip thermal treatments. The glass substrate hosts, on one side, hydrogenated amorphous silicon diodes, working as both temperature sensors and photosensors, and, on the other side, transparent thin films acting as heating sources. The main challenge of the work is the determination of the correct fabrication recipes in order to satisfy the compatibility of different microelectronic steps. The measured uniformity of temperature distribution, sensitivity of the temperature sensors, reverse dark current and spectral response of the photosensors demonstrate the successful technological integration and the suitability of the developed lab-on-glass to control the cell temperature and detect the BL emission with high sensitivity.

This work reports on design and fabrication of a compact lab-on-chip system, based on detection of electrochemiluminescence (ECL) through thin film sensors. The proposed system couples an optoelectronic platform to a disposable microfluidic chip. The optoelectronic platform includes amorphous silicon photosensors for detection of ECL, while the microfluidic chip contains the ECL electrodes and the biological solutions to be analyzed. Optoelectronic characterization of photosensors and preliminary test on the ECL electrodes by cycling voltammetry show the suitability of these devices for the achievement of low-noise and high sensitive system.

Lab-on-chip are analytical systems which, compared to traditional methods, offer significant reduction of sample, reagent, energy consumption and waste production. Within this framework, we report on the development and testing of an optoelectronic platform suitable for the on-chip detection of fluorescent molecules. The platform combines on a single glass substrate hydrogenated amorphous silicon photosensors and a long pass interferential filter. The design of the optoelectronic components has been carried out taking into account the spectral properties of the selected fluorescent molecule. We have chosen the [Ru(phen)2(dppz)]2+ which exhibits a high fluorescence when it is complexed with nucleic acids in double helix. The on-glass optoelectronic platform, coupled with a microfluidic network, has been tested in detection of double-stranded DNA (dsDNA) reaching a detection limit as low as 10 ng/µL.

This work presents the development and testing of an integrated system for on-chip detection of thermochemiluminescent biomolecules. The activation energy of the reaction is provided by a transparent structure of thin film heaters deposited on one side of a glass substrate. Light, passing through the substrate, reaches an array of amorphous silicon differential structure deposited on the opposite side of the glass substrate. The structure is designed to perform differential current measurements between a light- shielded diode, whose current is sensitive only to temperature, and a photosensor, sensitive to both incident light and temperature. The device therefore balances the thermal variations of the photodiode current and reduces the dark-current noise. These features make the presented system very appealing as highly miniaturized micro-analytical devices for biosensing applications.

This work presents a lab-on-chip system, which combines a glass-polydimethilsiloxane microfluidic network and an array of amorphous silicon photosensors for the diagnosis and follow-up of Celiac disease. The microfluidic chip implements an on-chip enzyme-linked immunosorbent assay (ELISA), relying on a sandwich immunoassay between antibodies against gliadin peptides (GPs) and a secondary antibody marked with horseradish peroxidase (Ig-HRP). This enzyme catalyzes a chemiluminescent reaction, whose light intensity is detected by the amorphous silicon photosensors and transduced into an electrical signal that can be processed to recognize the presence of antibodies against GPs in the serum of people affected by Celiac syndrome.The correct operation of the developed lab-on-chip has been demonstrated using rabbit serum in the microfluidic ELISA. In particular, optimizing the dilution factors of both sera and Ig-HRP samples in the flowing solutions, the specific and non-specific antibodies against GPs can be successfully distinguished, showing the suitability of the presented device to effectively screen celiac disease epitopes. Keywords: Lab-on-chip, Celiac disease, Microfluidics, On-chip detection, ELISA, Amorphous silicon photosensors

This paper presents the design and fabrication of a microfluidic structure on a glass substrate for fluid handling in lab-on-chip systems. A polydimethilsiloxane microfluidic network hosts a thermally actuated microvalve on one side of the glass slide, while, on the opposite side, a thin film metal heater acts as heat source for the actuation of the microvalve. The design of the system has been carried out using COMSOL Multiphysics. The width of the microchannel has been optimized taking into account the deformation of the valve membrane and the temperature needed to actuate the valve. In order to overcome the fluid leakage due to the shape mismatch between the deformed valve membrane and the rectangular cross-section of the channel, a microchannel with round-shaped cross-section has been simulated and subsequently fabricated by using a mold of positive photoresist AZ ® 40 XT. The reliability of the complete device has been tested and verified on several fabricated devices through repeated cycles of closing and opening of the microvalve.

Indium Tin Oxide (ITO) is widely used in solar cell devices for its excellent electrical and optical characteristics, such as high transparency in the Ultraviolet-Visible range and good conductivity (around 104W-1cm-1). In this work we have compared thin (70-150 nm) ITO layers deposited by Direct Current or Radio Frequency sputtering. We have used different substrate temperatures during film growthand have afterwards thermally annealed the samples at different temperatures up to 300 °C to investigate the effects on the electrical and optical properties of the material. We have found out that the different growth/annealing conditions induce changes in the optical properties of the samples as well as in the conductivity and carrier concentration. © 2018 IEEE.

This article presents the successful design, fabrication and testing of a miniaturized system integrating capillarity and electrowetting-on-dielectric (EWOD) technology in a microfluidic network. In particular, the change in hydrophobicity occurring at the interphase between a capillary channel and a hydrophobic layer has been exploited using EWOD as a stop-go fluid valve. The combination of capillary forces and EWOD technology to control the fluid movement opens the possibility to implement a wide variety of microfluidic configurations to perform different biomedical assays with a low-power consumption process. These assays could be easily and inexpensively integrated in lab-on-chip systems featuring small size and high-throughput characteristics.

The paper represents the “state of the art” on sustainability in construction materials. In Part 1 of the paper, issues related to production, microstructures, chemical nature, engineering properties, and durability of mixtures based on binders alternative to Portland cement were presented. This second part of the paper concerns the use of traditional and innovative Portland-free lime-based mortars in the conservation of cultural heritage, and the recycling and management of wastes to reduce consumption of natural resources in the production of construction materials. The latter is one of the main concerns in terms of sustainability since nowadays more than 75% of wastes are disposed of in landfills.

This review presents “a state of the art” report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1—the present paper—focuses on the use of binders alternative to Portland cement, including sulfoaluminate cements, alkali-activated materials, and geopolymers. Part 2 will be dedicated to traditional Portland-free binders and waste management and recycling in mortar and concrete production.

This paper presents the development of a compact optoelectronic device suitable for on-chip detection of fluorescent molecules. In order to obtain a highly integrated device, a long-pass multi-dielectric filter has been integrated with thin-film amorphous silicon photosensors on a single glass substrate. Filter rejects the excitation light, allowing the reduction of the distance between the source and the fluorescent site and avoiding the use of external optical component. The compatibility of the technological processes determined the materials and the temporal sequence of the device fabrication. The developed device has been designed for the fluorescence detection of ruthenium complex based molecules and tested, as a proof of concept, for the detection of double-stranded DNA down to 0.5 ng. Results demonstrate the correct operation of the integrated system in both rejecting the excitation light and in detecting the fluorescent signal, demonstrating the suitability of this optoelectronic platform in practical biomedical applications.

In this paper, we present an optoelectronic system-on-glass (SoG), suitable for detection of fluorescent molecule. It integrates, on the same glass substrate, an array of amorphous silicon (a-Si:H) photosensors and a thin film interferential filter. The system can be directly coupled with another glass substrate hosting a polydimethylsiloxane based microfluidic network where the fluorescent phenomena occur. The compatibility of the different technological steps to attain on the same glass substrate the photosensors and the filter determined the sequence, the selection of materials and the deposition parameters of the whole process. The electro-optical characterization of the photodiode, performed after the filter deposition, demonstrated the efficacy of the filter in reducing the excitation light. The system has been successfully tested using the ruthenium complex [Ru(phen)2(dppz)]2+, a fluorescent dye which works as DNA intercalating molecule. © Springer International Publishing AG 2018.

The present paper describes the development of an integrated lab-on-chip, in which viral DNA amplification with real-time on-chip detection is carried out under constant temperature of 65 °C. The lab-on-chip is composed of a disposable 10-μL polydimethylsiloxane reaction chamber which is thermally and optically coupled to a glass substrate that hosts a thin-film metallic resistive heater and thin-film amorphous silicon diodes which act as temperature and radiation sensors. A loop-mediated isothermal amplification (LAMP) technique was optimized to specifically amplify parvovirus B19 DNA and coupled with Bioluminescent Assay in Real Time (BART) technology to provide real-time detection of target DNA. The experimental results demonstrate the ability of the proposed device to discriminate among different concentrations of viral DNA with an excellent agreement with standard off-chip methods.

On-chip optical detection of chemiluminescent reactions is presented. The device is based on the integration of thin film hydrogenated amorphous silicon photosensors on a functionalized glass substrate ensuring both a good optical coupling and an optimal separation between biological or chemical reagents and the sensing elements. The sensor has been characterized and optimized using the chemiluminescent system composed by the enzyme horseradish peroxidase (HRP) and luminol/peroxide/enhancer cocktail. The detectability of HRP is at the attomole level with a sensitivity of 1.46 fA/fg. Experiments, involving the detection of immobilized bio-specific probes on the functionalized surface have been performed both in bulk and microfluidics regime, proving the ability of the system to effectively detect chemiluminescent reactions and their kinetics. In particular, results achieved using conventional polydimethylsiloxane microfluidics for samples and reagents handling confirmed the good detection capabilities of the proposed system.

In this paper we present a compact technological demonstrator including on the same glass substrate an electrowetting-on-dielectrics (EWOD) system, a linear array of amorphous silicon photosensor and a capillary-driven microfluidic channel. The proposed system comprises also a compact modular electronics controlling the digital microfluidics through the USB interface of a computer. The system provides therefore both on-chip detection and microfluidic handling needed for the realization of a ‘true’ Lab-on-Chip. The geometry of the photosensors has been designed to maximize the radiation impinging on the photosensor and to minimize the inter-site crosstalk, while the fabrication process has been optimized taking into account the compatibility of all the technological steps for the fabrication of the EWOD system, the photosensor array and the microfluidics channels. As a proof of the successful integration of the different technological steps we demonstrated the ability of the a-Si:H photosensors to detect the presence of a droplet over an EWOD electrode and the effective coupling between the digital and the continuous microfluidics, that can allow for functionalization, immobilization and recognition of biomolecules without external optical devices or microfluidic interconnections.

This work reports on the design, simulation and fabrication of an autonomous microfluidic network. It is a part of a highly integrated, new analytical platform for the multiparametric detection of bio-organic molecules in extra-terrestrial environment. The proposed microfluidic system, made in SU-8 3050, allows to obtain an autonomous microfluidic network able to have simultaneous capillary filling and fresh solution into each site of detection avoiding cross-contamination among different sites. Computational Fluid Dynamics (CFD) simulations have been carried in order to verify the proper operation of the designed microfluidic network and to optimize it. Technological processes have been refined and adapted in order to ensure good adhesion, using low-temperature and low-pressure bonding avoiding the risk of breaking the glass slides. Experiments have been conducted to verify the autonomous capillary filling of the entire network and its rinsing with buffer solution. The experimental results are in good agreement with the simulations.

In this paper, we present an improved microfluidic network based on polydimethylsiloxane (PDMS) and thin film heaters for thermal treatment of biomolecules in lab-on-chip systems. It relies on the series connection of two thermally actuated valves, at both inlet and outlet of the network, in order to reduce leakage of sample when its process temperature approaches 100 °C. The spatial arrangement of valves and microfluidic channels in between has been optimized using COMSOL Multiphysics, through the investigation of the system thermal behavior. Taking into account the simulation results, the geometries of the heaters have been defined following standard microelectronic technologies and the microfluidic network has been fabricated by soft lithography. The experiments demonstrate that with the proposed configuration the liquid evaporation is strongly reduced since more than 80% of the sample is recovered after a practical thermal treatment experiment.

This work combines a lab-on-chip device with an electronic system for the achievement of a small-scale and low-cost thermal treatment of biomolecules. The lab-on-chip is a 1.2 mm-thick glass substrate hosting thin film resistor acting as heater and, on the other glass side, amorphous silicon diodes acting as temperature sensors. The electronic system controls the lab-on-chip temperature through a Proportional-Integral-Derivative algorithm. In particular, an electronic board infers the temperature measuring the voltage across the amorphous silicon diodes, which are biased with a constant forward current of 50 nA, and drives the heater to achieve the set-point temperature. The characterization of the whole system has been carried out implementing the thermal cycles necessary in the polymerase chain reaction technique for amplification of DNA. To this purpose, the lab-on-chip has been thermally coupled with another glass hosting a microfluidic network made in polydimethilsiloxane, and the time evolution of temperature has been carefully monitored. The measured performances in terms of heating rate, cooling rate and settling time demonstrate that the proposed system completely fulfills the requirements of the investigated biological application.

This work presents a miniaturized lab-on-chip system suitable for monitoring the activity of living cells through the on-chip detection of their bioluminescence emission. The system integrates amorphous silicon diodes, acting as temperature and light sensors, and indium tin oxide film, acting as heater, on a single glass substrate. During its operation, the glass is thermally and optically coupled to the investigated cells and electrically connected to an electronic board, which controls the lab-on-chip temperature and monitors the sensor photocurrents. The proposed lab-on-chip is particularly attractive for the development of portable cell-based biosensors useful for biological activity monitoring as well as for cell cytotoxicity evaluation.

This work presents analysis and development of an evanescent waveguide sensor system, which integrates an amorphous silicon photodiode and a glass-diffused waveguide. Design of the system includes a study of thickness and refractive index of the transparent electrode of the diode, which are crucial parameters for the optimization of the optical coupling between the waveguide and the photodetector. Preliminary electro-optical measurements on the fabricated device show excellent system performances, and suggest its use for on-chip detection in lab-on-chip applications.

We present the design and fabrication of an evanescent waveguide sensor based on a-Si:H photodiodes for biomedical applications. The complete device presents a noise level lower than 2fA and a responsivity of 300mA/W at 532nm.

Here we present the design of an amorphous silicon photodetector integrated with an ion-exchanged waveguide on the same glass substrate in order to obtain an evanescent waveguide sensor for on-chip biomolecular recognition in Lab-on-Chip applications. We studied the behaviour of a monochromatic light in a channel waveguide and its coupling into the thin-film sensor, using COMSOL Multiphysics. Simulations show that the presence of the photodiode’s insulation layer and transparent electrode strongly affects the coupling efficiency between the waveguide and the sensor.

This paper presents the integration on the same glass substrate of an amorphous silicon photodiode and a diffused waveguide, to achieve an integrated evanescent waveguide sensor. Simulations performed with COMSOL Multiphysics show that the coupling efficiency between the waveguide and the photosensor is strongly affected by the presence of the passivation layer, and by thickness and refractive index of the transparent electrode of the photodiode. A first prototype has been fabricated using standard microelectronics techniques in a 6-masks process fiow. Electro-optical characterization, performed measuring the diode photocurrent with and without lighting the waveguide, shows the effectiveness of the optical coupling between diode and waveguide, and suggest its use for on-chip detection in lab-on-chip applications.

A lab-on-chip system, integrating an all-glass microfluidics and on-chip optical detection, was developed and tested. The microfluidic network is etched in a glass substrate, which is then sealed with a glass cover by direct bonding. Thin film amorphous silicon photosensors have been fabricated on the sealed microfluidic substrate preventing the contamination of the micro-channels. The microfluidic network is then made accessible by opening inlets and outlets just prior to the use, ensuring the sterility of the device. The entire fabrication process relies on conventional photolithographic microfabrication techniques and is suitable for low-cost mass production of the device. The lab-on-chip system has been tested by implementing a chemiluminescent biochemical reaction. The inner channel walls of the microfluidic network are chemically functionalized with a layer of polymer brushes and horseradish peroxidase is immobilized into the coated channel. The results demonstrate the successful on-chip detection of hydrogen peroxide down to 18 μM by using luminol and 4-iodophenol as enhancer agent.

In this paper, we report on the design, fabrication and characterization of a low cost, portable detection system able to quantify, in a rapid and reliable way, the contamination level of Ochratoxin A (OTA) in red wine. The operating principle is the real-Time monitoring of the natural fluorescence of OTA molecules during a chromatographic run on a thin layer chromatographic plate. The fluorescence is detected by an array of amorphous silicon photosensors whose photocurrents are directly proportional to the amount of OTA molecules present in the sample under analysis. By comparison with a reference sample the system is able to determine if the OTA contamination level is below or above the limit law for each food commodity. The system performances have been verified in real matrices analyzing several samples extracted from red wines obtaining a minimum detectable quantity of 0.2ng. © 2017 IEEE.

In this paper we present the integration, on a single glass substrate, of amorphous silicon photodiodes with an electrowetting-on-dielectric (EWOD) system as a technological demonstrator for achieving a compact, stand alone Lab-on-Chip (LoC) system. The EWOD system comprises a thin film of indium tin oxide (ITO) acting as actuation electrodes and a 1 μm-thick polydimethylsiloxane (PDMS) layer acting as both insulation and hydrophobic layer. The a-Si:H photosensors are ITO/p-type/intrinsic/n-type/metal stacked structures, aligned with the transparent EWOD electrodes, to detect optical signals generated inside (or modulated by) the liquid droplets handled by the digital microfluidic system. The fabrication process has been designed and performed taking into account the compatibility of all the technological steps of the photosensor and EWOD structures fabrication. The successful integration has been demonstrated checking the correct geometry of EWOD electrodes and measuring the optoelectronic performances of the a-Si:H photosensors at the end of the system fabrication. The correct operation and potentiality of the presented device has been assessed monitoring a photodiode current when a water droplet is moved forward and backward over the EWOD electrodes aligned with the photosensors.

The ion-exchange properties of a synthetic hydrosodalite (Na-hS) have been investigated by kinetic and thermodynamic analysis of exchange reactions of the original sodium form for lithium, potassium and calcium forms. Kinetic curves, modelled by a Langmuir-type equation, revealed that exchange rate for lithium and for potassium are of the same order, whereas they are two order faster than for calcium. Thermodynamic analysis of the cation exchange isotherms pointed out that sodalite is selective for sodium over the other three cationic forms examined, which is consistent with the preference exhibited by the sodalite type for sodium environments, either in natural or in laboratory crystallization. Na/Li and Na/Ca exchanges are incomplete, whereas unexpectedly Na/K exchange turns out to be complete, even though K+ dimension exceeds the width of the access window to sodalite cages. The obtained results have been discussed in terms of Eisenman–Sherry theory, pointing out agreements and discrepancies.

In this paper, we present the preliminary results of an ELISA-on-chip device, intended as a technological demonstrator of a novel analytical system suitable for the diagnosis and follow-up of celiac disease. The idea of the work is to combine an array of amorphous silicon photosensors with a pattern of a poly(2-hydroxyethyl methacrylate) polymer brush film, which acts as anchor for the immobilization of gliadin peptides containing the celiac disease epitopes. Recognition relies on a sandwich immunoassay between antibodies against the peptides and secondary antibodies marked with horseradish peroxidase to obtain a chemiluminescent signal. Detection is based on the measurement of photocurrent induced in the array of amorphous silicon photosensors by the chemiluminescent signal. An ad-hoc procedure has been developed in order to enable the fabrication of the photodiode array and the polymer brush pattern on the two sides of the same glass substrate ensuring the compatibility of the different technological steps. The sensitivity and the selectivity of the chip for multiplex immunoassays were demonstrated using two gliadin peptides (VEA and DEC). In particular, we found that the average amount of the bound HRP revealed by our analytical protocol is 3.5(±0.3) × 10−6 pg μm−2 and 0.85(±0.3) × 10−6 pg μm−2 for specific and non-specific interactions, respectively.

This paper describes a novel and easily manufacturable method for increasing the thermal resistance of microheaters fabricated on glass substrates, thus decreasing the thermal dissipation of the devices. An automatic sawing machine was exploited to dig 240 μm wide trenches in order to thermally isolate the heater from the glass substrate and four different layouts of the trenches have been investigated. An improvement of the thermal resistance up to 217% on a heat sink and 30% in air has been obtained. The thermal capacitance was also considerably decreased, thus improving the dynamic thermal behavior.

Objective: To evaluate Bacille Calmette-Guérin (BCG) effects after clinically isolated syndromes (CIS). Methods: In a double-blind, placebo-controlled trial, participants were randomly assigned to receive BCG or placebo and monitored monthly with brain MRI (6 scans). Both groups then entered a preplanned phase with IM interferon-?-1a for 12 months. From month 18 onward, the patients took the disease-modifying therapies (DMTs) that their neurologist considered indicated in an open-label extension phase lasting up to 60 months. Results: Of 82 randomized subjects, 73 completed the study (33 vaccinated and 40 placebo). During the initial 6 months, the number of cumulative lesions was significantly lower in vaccinated people. The relative risks were 0.541 (95% confidence interval [CI] 0.308-0.956; p = 0.03) for gadolinium-enhancing lesions (the primary endpoint), 0.364 (95% CI 0.207-0.639; p = 0.001) for new and enlarging T2-hyperintense lesions, and 0.149 (95%CI 0.046-0.416; p = 0.001) for new T1-hypointense lesions. The number of total T1-hypointense lesions was lower in the BCG group at months 6, 12, and 18: mean changes from baseline were - 0.09 ± 0.72 vs 0.75 ± 1.81 (p = 0.01), 0.0 ± 0.83 vs 0.88 ± 2.21 (p = 0.08), and -0.21 ± 1.03 vs 1.00 ± 2.49 (p = 0.02). After 60 months, the cumulative probability of clinically definite multiple sclerosis was lower in the BCG 1 DMT arm (hazard ratio = 0.52, 95% CI 0.27-0.99; p < 0.05), and more vaccinated people remained DMT-free (odds ratio = 0.20, 95% CI 0.04-0.93; p = 0.04). Conclusions: Early BCG may benefit CIS and affect its long-term course. Classification of evidence: BCG, as compared to placebo, was associated with significantly reduced development of gadolinium-enhancing lesions in people with CIS for a 6-month period before starting immunomodulating therapy (Class I evidence). © 2013 American Academy of Neurology.

Lab-on-Chip are miniaturized systems able to perform biomolecular analysis in shorter time and with lower reagent consumption than a standard laboratory. Their miniaturization interferes with the multiple functions that the biochemical procedures require. In order to address this issue, our paper presents, for the first time, the integration on a single glass substrate of different thin film technologies in order to develop a multifunctional platform suitable for on-chip thermal treatments and on-chip detection of biomolecules. The proposed System on-Glass hosts thin metal films acting as heating sources; hydrogenated amorphous silicon diodes acting both as temperature sensors to monitor the temperature distribution and photosensors for the on-chip detection and a ground plane ensuring that the heater operation does not affect the photodiode currents. The sequence of the technological steps, the deposition temperatures of the thin films and the parameters of the photolithographic processes have been optimized in order to overcome all the issues of the technological integration. The device has been designed, fabricated and tested for the implementation of DNA amplification through the Polymerase Chain Reaction (PCR) with thermal cycling among three different temperatures on a single site. The glass has been connected to an electronic system that drives the heaters and controls the temperature and light sensors. It has been optically and thermally coupled with another glass hosting a microfluidic network made in polydimethylsiloxane that includes thermally actuated microvalves and a PCR process chamber. The successful DNA amplification has been verified off-chip by using a standard fluorometer.

This work presents a miniaturized system combining, on the same microfluidic chip, capillarity and electrowetting-on-dielectric (EWOD) techniques for movement and control of fluids. The change in hydrophobicity occurring at the edge between a capillary channel and a hydrophobic layer is successfully exploited as a stop-and-go valve, whose operation is electronically controlled through the EWOD electrodes. Taking into account the variety of microfluidic operation resulting from the combination of the two handling techniques and their characteristic features, this work prompts the development of autonomous, compact and low-power consumption lab-on-chip systems.

Lab-on-chip devices are ideal candidates for use in space missions where experiment automation, system compactness, limited weight and low sample and reagent consumption are required. Currently, however, most microfluidic systems require external desktop instrumentation to operate and interrogate the chip, thus strongly limiting their use as stand-alone systems. In order to overcome the above-mentioned limitations our research group is currently working on the design and fabrication of “true” lab-on-chip systems that integrate in a single device all the analytical steps from the sample preparation to the detection without the need for bulky external components such as pumps, syringes, radiation sources or optical detection systems. Three critical points can be identified to achieve ‘true’ lab-on-chip devices: sample handling, analytical detection and signal transduction. For each critical point, feasible solutions are presented and evaluated. Proposed microfluidic actuation and control is based on electrowetting on dielectrics, autonomous capillary networks and active valves. Analytical detection based on highly specific chemiluminescent reactions is used to avoid external radiation sources. Finally, the integration on the same chip of thin film sensors based on hydrogenated amorphous silicon is discussed showing practical results achieved in different sensing tasks.