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Inkjet printing is an established technology that has been revisited in recent years for the low-cost and easy production of electrical sensing and biosensing systems. With this technique, it is possible to produce flexible microsystems on eco-compatible substrates such as polymers and paper. In this sense, we investigated the printing performances of a common office inkjet printer and of a commercial conducting ink, to produce aptamer-based electrochemical biosensors for antibiotics detection. During our analysis we characterized both the morphological and electrical properties of the printed electrodes, considering also their stability over time and tuning all the parameters to obtain reproducible micrometric systems. The produced devices proved to be able to undergo aptamer functionalization and to detect Ampicillin, a common used antibiotic, in few minutes with a LOD of 10 μg/ml in milk. Therefore, in this preliminary work we demonstrated the feasibility of low-cost customized inkjet-printed biosensors, and their possible use to prevent both antibiotic contaminations and antibiotic resistance development.

Inkjet printing technology is showing a disruptive potential for low-cost optical and electrochemical biosensors fabrication. This technology is becoming affordable for every laboratory, potentially allowing every research group to implement a biosensors fabrication platform with consumer inkjet printers, commercially available inks and smartphones for readout. In the present work we developed an example of such platform testing several inks, printers, and substrates. We defined and optimized the protocols assessing the printing limits and the fabricated biosensors electrochemical properties in standard solutions. Our platform has a total cost of less than 450 Euro and a single sensor fabrication cost of 0.026 Euro. Finally, we tested the sensitivity of smartphone-performed impedance measurements with printed biosensors surface coverage by Self Assembling Monolayers (SAM), validating them with standard instruments.

In this work, veal urine dilutions in Hepes-buffered Ringer’s solution (HBRS) are tested by both UV-visible absorption spectroscopy and Cyclic Voltammetry (CV) to assess their viability as mediums for the detection of lactate, through the Lactate Dehydrogenase enzyme (LDH) reaction which involves the formation of NADH. Several data analysis algorithms for the recorded CV data are proposed and compared, in order to optimize the NADH detection in the urine samples dilutions. UV-visible spectroscopy was adopted as reference for NADH quantification.

Bacteriophages are responsible for significant material and time losses in the dairy industry. This because these viruses infect the selected lactic starter cultures used for milk fermentation, i.e., the first stage toward cheese production. Standard detection techniques are time- and labor-consuming, causing huge costs related to production plant sanitation and product wasting. A new type of biosensor for early detection of bacteriophage contamination is highly demanded by the milk processing market, and inkjet-printed electrochemical sensors could be the answer. Inkjet printing is a well-known technology that has been revisited in recent years, using silver nanoparticle (AgNP) based inks for low-cost and easy fabrication of sensing and biosensing systems on flexible and eco-compatible substrates. In this research, we studied inkjet printing for the manufacturing of both interdigitated electrodes arrays (IDEAs), and a versatile system to monitor bacterial cultures by electrochemical impedance spectroscopy (EIS). In particular, we studied this biosensing system for the detection of bacteriophages by comparing its performance with standard microbiological methods. We performed electrical and morphological characterizations of the devices produced with a consumer-use inkjet printer with commercial AgNPs ink on flexible substrates, such as office paper, polyethylene (PET), and photo paper. We used light microscopy optical analysis, profilometry, atomic force microscopy (AFM), and scanning electron microscopy (SEM) imaging to define the objects resolution, their real dimensions, and thickness. We also investigated the devices&rsquo, conductivity and layout, by EIS measurements with a standard buffer solution, i.e., phosphate buffered saline (PBS). Finally, we tested our system by monitoring Lactococcus lactis cultures and bacteriophage infection. We compared the results to those obtained by two standard microbiological methods in terms of response time, proving that our technique requires less than half the time of other methods and no specialized personnel.

This work describes a Combined Simulation System (CSS) able to predict the electrical behaviour of a metal electrode in contact with an electrolyte. The system is based on a mixture of Lumped Parameters Equivalent Electrical Circuits (LPEEC) and Pseudo-Distributed Elements (PDE): a PDE is a network of basic equivalent electrical circuits, e.g. resistor and capacitor parallels, in which a geometrical information can be retained. Electrochemical Impedance Spectroscopy (EIS) measurements have been performed on a standard solution of known electrical conductivity with Micro-Electrodes Array (MEA) devices in order to investigate set-up parasitic elements and electrochemical interfaces parameters. CSS performance has been compared to usual LPEEC fit approach in terms of both results accuracy and solving time.

This article outlines an exploratory comparative study of the vocal expression of emotions in Chinese versus Italian cultures. Given a strong relationship between voice and emotion, it is of special interest to analyze whether and how this connection may covariate with cultural influences in shaping emotions. Forty-eight undergraduates (29 Chinese and 19 Italian) are asked to read aloud short stories inducing different emotions (joy, sadness, anger, fear, contempt, pride, guilt, and shame) within a scenario approach. Subsequently, acoustic (sonographic) analysis is carried out on the recorded readings. On the one hand, the results confirm that different emotions may be expressed via variations in the modulation of vocal cues, in both cultures; on the other hand, differences in the specific patterns of vocal cues in expressing emotions are identified between Chinese and Italian participants. Theoretical implications of these findings are discussed. © 2008 Sage Publications.

Many fundamental researches in molecular biology deal with molecules which need to be inserted into the plasmatic membrane of living (cultured) cells. Working with single cells represents an important improvement for some of these studies, since it allows experiments where the behavior of a modified cell in a non modified context can be studied. This result can be achieved with a Multi Electrode Array which can locally break down the cell membrane, allowing molecules to enter the cell and acting as a multi-site, single-cell, electroporation biochip. Electrochemical impedance spectroscopy (EIS) measurements, coupled with an accurate electrical model of the biochip and cell interface, are used to detect the presence of a cell above the biochip microelectrode. This allows fully automatic single cell electroporation.

A novel compact architecture implementi ng grating-coupled surface plasmon resonance (GCSPR ) based on polarization modulation in conical mounting is presented. In this system a plasmonic grating is azimuthally rotated in order to support the excitation of high-sensitivity surface plasmon polaritons (SPPs). At SPP resonance, a scan of the incident polarization is performed before and after the binding event and the phase term of the output trend is exploited as sensing parameter. The mechanical complexity of the SPR system is significantly reduced and a resolution down to 10 -7 refractive index units is assured. In this work a numerical study of the polarization-based grating-coupled SPR technique is performed and analyzed with Chandezon’s method. Therefore an experimental test on an assembled prototype is presented and applied to the detection of binding events on the grating surface (avidin/biotin reaction, DNA/PNA probes). Keywords: surface plasmon resonance, metallic gratings, conical mounting, polarization modulation, sensing, biotin/avidin, PNA, DNA

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