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In this work we determined the Sensitivity (estimated as the I50 value) and Limit of Detection (LOD) for the immunodetection of carbaryl pesticide with two different types of acoustic wave sensors: High Fundamental Frequency Quartz Crystal Microbalance (HFF-QCM) and Love Mode Surface Acoustic Wave (LM-SAW). Results were compared with others previously reported using different sensors and techniques, like traditional QCM, Surface Plasmon Resonance (SPR) and Enzyme-Linked ImmunoSorbent Assay (ELISA). We used the AWS-A10 research platform (AWSensors, Spain) to perform the experiments. We obtained I50 values of 0.31 μg/L and 0.66 μg/L, and LODs of 0.09 μg/L and 0.14 μg/L, for 120 MHz LM-SAW and 100 MHz HFF-QCM devices, respectively. Both the sensitivities and LODs of the immunosensors improved previously reported SPR and QCM results by one and two orders of magnitude, respectively, and reached those of ELISA. [ABSTRACT FROM AUTHOR]

Abstract: This paper evaluates the performance characteristics of a new miniaturized lateral capacitive accelerometer with a high bandwidth as well as a high sensitivity, utilizing a low thermal budget SiGe MEMS technology. The accelerometer combines a 4μm SiGe structural layer thickness with a small capacitive sensing gap of 500nm, leading to an improvement in sensitivity along with large bandwidth and a reduction in overall dimension compared to conventional accelerometers, which have gaps in the order of 1μm. The accelerometer studied here is targeted for a maximum operational range of ±2g. [Copyright &y& Elsevier]

Abstract: Impedimetric biosensors are promising for label-free, real-time, sensitive and selective detection of bacteria. However, these sensors do typically not detect below 103 colony forming unit (CFU) per ml in absence of dielectrophoresis and labels. This work shows that the noise source due to random distributions of bacteria on the biosensor surface strongly restricts the limit of detection (LOD) for an interdigitated microelectrode (IDE) configuration. 3D finite-element simulations also indicate that the bacteria diameter and the surface coverage influence both the sensitivity and the signal-to-noise ratio (SNR). Optimization of the IDE design suggests that the SNR is maximized, i.e., the LOD is minimized, as the electrode gap is approximately five times the bacteria diameter and the electrode width and thickness are minimized and maximized with regards to current technological limitations, respectively. The paper finally highlights the critical design trade-off between SNR and sensitivity maximization. [Copyright &y& Elsevier]

Abstract: MEMS technology is expected to play a significant role in future space missions provided the effects of radiation on the reliability of MEMS devices is well understood . Radiation induced dielectric charging has been identified as a mechanism which can potentially limit the reliability of electrostatically actuated MEMS devices . The response of piezoresistive and PZT actuated MEMS was also found to change after exposure to different types of radiation . It is however necessary to further investigate the effect of radiation and especially neutrons on the electromechanical properties of various materials that are used in microfabrication . In this work we present results from mechanical and electrical tests on different materials before and after exposure to neutrons radiation. [Copyright &y& Elsevier]

Abstract: In hospital environment, the real-time monitoring of a patient’s respiration can provide valuable information to the physicians. Two examples are given by measuring the load effort during re-educative exercises or by detecting sleep apnoea. Using an oronasal sensor previously demonstrated performs a non-invasive recording of the breath activity. The sensor operates on condensation/evaporation cycles and provides an electrical signal representative of the respiration phase. We present in this paper a robust data acquisition and treatment algorithm that copes with the wide variations seen by the sensor in order to determine the respiratory frequency. To reduce both the computational load and the noise on the estimated frequency, the Median Absolute Deviation (MAD) was used in order to detect spurious signal segments. A real-time estimation of the respiratory state of elderly patients in hospital demonstrates the efficiency of the presented algorithm. Currently, a observation window of 5 s is processed in around 0.5 s. [ABSTRACT FROM AUTHOR]

Abstract: Silicon-on-Insulator (SOI) technology, with unique properties such as harsh environment resistance and lower power consumption [1], is presented here as a platform for CMOS and MEMS co-integration. An original CMOS-compatible process has been developed for the design and the co-fabrication of out-of-plane (3D) movable cantilevers and ring oscillators (RO) circuits on the same chip. The measured transducer, by deflection of the out-of-plane MEMS component, shows until 10% variation of the frequency under different flow rates. [ABSTRACT FROM AUTHOR]

Abstract: Rapid, real-time detection of pathogenic microorganisms is an emerging evolving field of research, especially for microorganisms that pose a major threat to public health. Alumina covered interdigitated capacitive microsensors were previously designed in our laboratory for DNA hybridization electrical detection (LOD of 30 nM target DNA). The device is constructed with standard CMOS materials. We show here that when coated with an appropriate anti- Staphylococcus aureus monoclonal antibody (MoAb), this device also permits to specifically detect this bacteria. The binding of bacteria to the microsensors induce a significant capacitance shift that is proportional to the amount of immobilized bacteria, thus enabling a possible quantitative analysis. [Copyright &y& Elsevier]

Abstract: Novel technologies for synthesis of nano-crystalline diamond (NCD) enable industrial production allowing large area deposition on a variety of substrate materials – at reasonable price. New perspectives for future innovative products emerge demonstrated by two case studies in the field of micro electro-mechanical systems (MEMS) sensors (case a) and medical implant devices (case b). a) This study comes as a preliminary step towards the integration of NCD thin film membranes in gravimetric sensors with low detection limits. We investigate theoretically and experimentally the mass sensing characteristics of composite thin Film Bulk Acoustic Resonator (FBAR) as a function of the side exposed to a mass perturbation. b) The aim of this study was to demonstrate the influence of different surface terminations of NCD on surface potentials and subsequently its influence on in vivo connective tissue healing. NCD-coated implants were evaluated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM)-surface potential measurements. After in vivo integration of the NCD-membranes into the subdermal layer of Wistar rats and subsequent histological evaluation it was demonstrated that the number of cells increased significantly at the O-terminated NCD and the scar tissue formed was less tight. Thus, a promising technique for controlling connective tissue adhesion in vivo is presented. [Copyright &y& Elsevier]

Abstract: Impedimetric sensors can be used for the detection of biological targets, such as bacteria. In this paper, 3D finite-element simulations show that random distributions of bacteria on interdigitated microelectrode sensor surfaces restrict their limit of detection (LOD). We demonstrate the strong influence of the bacteria diameter, surface coverage and electrode geometry on both the sensitivity and the signal-to-noise ratio (SNR). Particularly, we optimize the microelectrode design to maximize the SNR and hence the LOD, and establish that the optimal electrode gap is approximately four times the bacteria diameter. Furthermore, we show that the electrode width and thickness should respectively be minimized and maximized in the considered range with regards to current technological limitations. The paper finally highlights and discusses, from the designer point of view, the critical design tradeoff between SNR and sensitivity maximization. [Copyright &y& Elsevier]

Abstract The EuNetAir Joint Exercise focused on the evaluation and assessment of environmental gaseous, particulate matter (PM) and meteorological microsensors versus standard air quality reference methods through an experimental urban air quality monitoring campaign. This work presents the second part of the results, including evaluation of parameter dependencies, measurement uncertainty of sensors and the use of machine learning approaches to improve the abilities and limitations of sensors. The results confirm that the microsensor platforms, supported by post processing and data modelling tools, have considerable potential in new strategies for air quality control. In terms of pollutants, improved correlations were obtained between sensors and reference methods through calibration with machine learning techniques for CO (r2 = 0.13–0.83), NO 2 (r2 = 0.24–0.93), O 3 (r2 = 0.22–0.84), PM10 (r2 = 0.54–0.83), PM2.5 (r2 = 0.33–0.40) and SO 2 (r2 = 0.49–0.84). Additionally, the analysis performed suggests the possibility of compliance with the data quality objectives (DQO) defined by the European Air Quality Directive (2008/50/EC) for indicative measurements. Highlights • Several air quality microsensors were tested against reference methods. • Improved correlation between CO, NO2, O3, PM10, PM2.5, SO2 sensors and reference methods through calibration with machine learning techniques. • Parameter dependencies and measurement uncertainty of sensors were evaluated. • Possibility of compliance with DQO of the AQD for indicative measurements. • Microsensors can improve spatiotemporal data resolution to complement current monitoring networks. [ABSTRACT FROM AUTHOR]

We present a (1-D) SCAPS device model to address the following: (i) the surface passivation mechanisms (i.e. field-effect and chemical), (ii) their impact on the CIGS solar cell performance for varying CIGS absorber thickness, (iii) the importance of fixed charge type (+/−) and densities of fixed and interface trap charges, and (iv) the reasons for discrete gains in the experimental cell efficiencies (previously reported) for varying CIGS absorber thickness. First, to obtain a reliable device model, the proposed set of parameters is validated for both field-effect (due to fixed charges) and chemical passivation (due to interface traps) using a simple M-I-S test structure and experimentally extracted values (previously reported) into the SCAPS simulator. Next, we provide figures of merits without any significant loss in the solar cell performances for minimum net −Q f and maximum acceptable limit for D it , found to be ∼5 × 10 12 cm −2 and ∼1 × 10 13 cm −2 eV −1 respectively. We next show that the influence of negative fixed charges in the rear passivation layer (i.e. field-effect passivation) is more predominant than that of the positive fixed charges (i.e. counter-field effect) especially while considering ultra-thin (<0.5 μm) absorber layers. Furthermore, we show the importance of rear reflectance on the short-circuit photocurrent densities while scaling down the CIGS absorber layers below 0.5 μm under interface chemical and field-effect passivation mechanisms. Finally, we provide the optimal rear passivation layer parameters for efficiencies greater than 20% with ultra-thin CIGS absorber thickness (<0.5 μm). Based on these simulation results, we confirm that a negatively charged rear surface passivation with nano-point contact approach is efficient for the enhancement of cell performances, especially while scaling down the absorber thickness below 0.5 μm. [ABSTRACT FROM AUTHOR]

The 1st EuNetAir Air Quality Joint Intercomparison Exercise organized in Aveiro (Portugal) from 13th–27th October 2014, focused on the evaluation and assessment of environmental gas, particulate matter (PM) and meteorological microsensors, versus standard air quality reference methods through an experimental urban air quality monitoring campaign. The IDAD-Institute of Environment and Development Air Quality Mobile Laboratory was placed at an urban traffic location in the city centre of Aveiro to conduct continuous measurements with standard equipment and reference analysers for CO, NO x , O 3 , SO 2 , PM10, PM2.5, temperature, humidity, wind speed and direction, solar radiation and precipitation. The comparison of the sensor data generated by different microsensor-systems installed side-by-side with reference analysers, contributes to the assessment of the performance and the accuracy of microsensor-systems in a real-world context, and supports their calibration and further development. The overall performance of the sensors in terms of their statistical metrics and measurement profile indicates significant differences in the results depending on the platform and on the sensors considered. In terms of pollutants, some promising results were observed for O 3 (r 2 : 0.12–0.77), CO (r 2 : 0.53–0.87), and NO 2 (r 2 : 0.02–0.89). For PM (r 2 : 0.07–0.36) and SO 2 (r 2 : 0.09–0.20) the results show a poor performance with low correlation coefficients between the reference and microsensor measurements. These field observations under specific environmental conditions suggest that the relevant microsensor platforms, if supported by the proper post processing and data modelling tools, have enormous potential for new strategies in air quality control. [ABSTRACT FROM AUTHOR]

This work describes the development of a characterization method for biofunctionalized surfaces and its use for biosensor applications. The method is based on the processing of fluorescence images obtained by confocal microscopy. It retrieves quantitative data about the quantity and distribution of surface bound biomolecules, used to improve a biosensor performances in terms of specificity and sensitivity. Two biofunctionalization protocols were compared using the developed tools based on the fluorescence intensity, the surface coverage and the homogeneity of repartition of the fluorescence. In addition, the stability of the layer under flow, as well as the reproducibility and robustness of the protocols were evaluated. [ABSTRACT FROM AUTHOR]

Point-of-care (PoC) diagnostics for bacterial detection offer tremendous prospects for public health care improvement. However, such tools require the complex combination of the following performances: rapidity, selectivity, sensitivity, miniaturization and affordability. To meet these specifications, this paper presents a new selectivity method involving lysostaphin together with a CMOS-compatible impedance sensor for genus-specific bacterial detection. The method enables the sample matrix to be directly flown on the polydopamine-covered sensor surface without any pre-treatment, and considerably reduces the background noise. Experimental proof-of-concept, explored by simulations and confirmed through a setup combining simultaneous optical and electrical real-time monitoring, illustrates the selective and capacitive detection of Staphylococcus epidermidis in synthetic urine also containing Enterococcus faecium . While providing capabilities for miniaturization and system integration thanks to CMOS compatibility, the sensors show a detection limit of ca. 10 8 (CFU/mL).min in a 1.5 μL microfluidic chamber with an additional setup time of 50 min. The potentials, advantages and limitations of the method are also discussed. [ABSTRACT FROM AUTHOR]

Impedimetric biosensors with a passivation layer, also called capacitive biosensors, have recently shown great promise towards sensitive, selective and rapid detection of pathogen bacterial cells. However, few studies focus on their modeling, yet critical for the optimization of their sensitivity. To address this issue, we propose a comprehensive framework by developing analytical models and 2D numerical simulations of passivated interdigitated microelectrodes (IDEs) with adherent bacterial cells in electrolyte. While models provide a qualitative and semi-quantitative analysis of the AC impedance spectroscopy based on the system cutoff frequencies, finite element method (FEM) simulations based on Poisson–Nernst–Planck equations enable accurate quantification of the sensitivity to bacteria versus the applied frequency thanks to modeling of complex phenomena such as ion transport, surface and space charges, multi-shell bacterial dielectric properties and sensor topology. These numerical simulations are assessed by experimental results and compared to analytical models. [ABSTRACT FROM AUTHOR]

• Studying the benefits of in-situ thermal annealing to recover nMOSFET after irradiation. • Noise measurements confirms the creation of oxide defects at the gate-oxide after irradiation. • The radiation-induced trap is estimated to be localized at 5.4 nm from the Si-SiO 2 interface. • Total recovery of the initial characteristics has been achieved in the nMOS transistor. This paper demonstrates a procedure for complete in-situ recovery of on-membrane CMOS devices from total ionizing dose (TID) defects induced by gamma radiation. Several annealing steps were applied using an integrated micro-heater with a maximum temperature of 365 °C. The electrical characteristics of the on-membrane nMOSFET are recorded prior and during irradiation (up to 348 krad (Si)), as well as after each step of the in-situ thermal annealing. High-resolution current sampling measurements reveal the presence of oxide defects after irradiation, with a clear dominant single-trap signature in the random telegraph noise (RTN) traces. Drain current over time measurements are used for the trap identification and further for the defects' parameters extraction. The power spectral density (PSD) curves confirm a clear dominance of the RTN behavior in the low-frequency noise. A radiation-induced oxide trap is detected at 5.4 nm from the Si-SiO 2 interface, with an energy of 0.086 eV from the Fermi level in the bandgap. After annealing, the RTN behavior vanishes with a further important reduction of flicker noise. Low-frequency noise measurements of the transistor confirmed the neutralization of oxide defects after annealing. The electro-thermal annealing of the nMOSFET allows a total recovery of its original characteristics after being severely degraded by radiation-induced defects. [ABSTRACT FROM AUTHOR]