Microsyringe-based deposition of two-dimensional and three-dimensional polymer scaffolds with a well-defined geometry for application to tissue engineering.

A technique for controlled deposition of biomaterials and cells in specific and complex architectures is described. It employs a highly accurate three-dimensional micropositioning system with a pressure-controlled syringe to deposit biopolymer structures with a lateral resolution of 5 microm. The pressure-activated microsyringe is equipped with a fine-bore exit needle and a wide variety of two- and three-dimensional patterns on which cells to be deposited can adhere. The system has been characterized in terms of deposition parameters such as applied pressure, motor speed, line width and height, and polymer viscosity, and a fluid dynamic model simulating the deposition process has been developed, allowing an accurate prediction of the topological characteristics of the polymer structures.

A comparative study of protein immobilization techniques for optical immunosensors.

This paper presents the results of a study of a number of antibody immobilization techniques for application to optical immunosensors. In particular, well-known methods such as covalent binding and physical adsorption have been extended to the Langmiur-Blodgett method in an attempt to improve the density and possibly the uniformity of orientation of monoclonal antibodies on an optical surface. The surface density of active immobilized antibodies was determined from enzyme immunoassay and their thickness and refractive index were deduced from ellipsometry. It is shown that, although high surface densities (500 ng/cm2) of antibody can be obtained, the major obstacle to the detection of low concentrations of antigens or haptens is the non-specific binding of foreign molecules to the sensing surface.

Detection of incipient object slippage by skin-like sensing and neural network processing.

Detection of incipient slippage is of great importance in robotics for the control of grasping and manipulation tasks. Together with fine-form reconstruction and primitive recognition, it has to be the main feature of an artificial tactile system. The system presented here is based on a neural network used to detect incipient slippage and on a skin-like sensor sensible to normal and shear stresses. Normal and shear stresses components inside the sensor are the input data of the neural net. An important feature of the system is that the a priori knowledge of the friction coefficient between the sensor and the object being manipulated is not needed. To validate the method we worked on both simulated and experimental data. In the first case, the finite element method is used to solve the direct problem of elastic contact in its full nonlinearity by resorting to the lowest number of approximations regarding the real problem. Simulation has shown that the network learns and is robust to noise. Then an experimental test was carried out. Experimental results show that, in a simple case, the method is able to detect the insipiency of slippage between an object and the sensor.

Strain sensing fabric for hand posture and gesture monitoring.

Monitoring body kinematics and analyzing posture and gesture is an area of major importance in bioengineering and several other connected disciplines such as rehabilitation, sport medicine and ergonomics. Recent developments of new smart materials consent the realization of a new generation of garments with distributed sensors. What we present here is a sensing glove able to detect the posture and movements of the hand.

Artificial kinesthetic systems for telerehabilitation.

Artificial sensory motor systems are now under development in a truly wearable form using an innovative technology based on electroactive polymers. The integration of electroactive polymeric materials into wearable garments endorses them with strain sensing and mechanical actuation properties. The methodology underlying the design of haptic garments has necessarily to rely on knowledge of biological perceptual and motor processes which is, however, scattered and fragmented. Notwithstanding, the combined use of new polymeric electroactive materials in the form of fibers and fabrics with emerging concepts of biomimetic nature in sensor data analysis, pseudomuscular actuator control and biomechanical design may not only provide new avenues toward the realization of truly wearable kinesthetic and haptic interfaces, but also clues and instruments to better comprehend human manipulative and gestual functions. In this talk the conception, early stage implementation and preliminary testing of a fabric-based wearable interface endowed with spatially redundant strain sensing and distributed actuation are illustrated with reference to a wearable upper limb artificial kinesthesia system, intended to be used in telerehabilitation of post stroke patient.

A feasibility study of yarns and fibers with annexed electronic functions: the ARIANNE project.

In this paper several issues concerning the development of fibers endowed with electronic functions will be presented and discussed. In particular, issues concerning materials, structures, electronic models and the mechanical constraints due to textile technologies will be detailed. All these aspects have been studied in the framework of the project ARIANNE, funded by the European Community during the V Frame Programme.

Daily-life monitoring of stroke survivors motor performance: the INTERACTION sensing system.

The objective of the INTERACTION Eu project is to develop and validate an unobtrusive and modular system for monitoring daily life activities, physical interactions with the environment and for training upper and lower extremity motor function in stroke subjects. This paper describes the development and preliminary testing of the project sensing platform made of sensing shirt, trousers, gloves and shoes. Modular prototypes were designed and built considering the minimal set of inertial, force and textile sensors that may enable an efficient monitoring of stroke patients. The single sensing elements are described and the results of their preliminary lab-level testing are reported.

A neuron-astrocyte transistor-like model for neuromorphic dressed neurons.

Experimental evidences on the role of the synaptic glia as an active partner together with the bold synapse in neuronal signaling and dynamics of neural tissue strongly suggest to investigate on a more realistic neuron-glia model for better understanding human brain processing. Among the glial cells, the astrocytes play a crucial role in the tripartite synapsis, i.e. the dressed neuron. A well-known two-way astrocyte-neuron interaction can be found in the literature, completely revising the purely supportive role for the glia. The aim of this study is to provide a computationally efficient model for neuron-glia interaction. The neuron-glia interactions were simulated by implementing the Li-Rinzel model for an astrocyte and the Izhikevich model for a neuron. Assuming the dressed neuron dynamics similar to the nonlinear input-output characteristics of a bipolar junction transistor, we derived our computationally efficient model. This model may represent the fundamental computational unit for the development of real-time artificial neuron-glia networks opening new perspectives in pattern recognition systems and in brain neurophysiology.

Wearable monitoring of lumbar spine curvature by inertial and e-textile sensory fusion.

This paper describes the design, the development and the preliminary testing of a wearable system able perform a real time estimation of the local curvature and the length of the spine lumbar arch. The system integrate and fuse information gathered from textile based piezoresistive sensor arrays and tri-axial accelerometers. E-textile strain sensing garments suffer from non-linearities, hysteresis and long transient, while accelerometers, used as inclinometers, present biased values and are affected by the system acceleration due to subject movements. In this work, focused on the wearability and comfort of the user, we propose a fusion of the information deriving from the two class of sensors to reduce their intrinsic errors affecting measurements. Comparative evaluation of system performances with stereophotogrammetric techniques shows a 2% error in lumbar arch length reconstruction.

Heart rate and accelerometer data fusion for activity assessment of rescuers during emergency interventions.

The current state of the art in wearable electronics is the integration of very small devices into textile fabrics, the so-called ¿smart garment.¿ The ProeTEX project is one of many initiatives dedicated to the development of smart garments specifically designed for people who risk their lives in the line of duty such as fire fighters and Civil Protection rescuers. These garments have integrated multipurpose sensors that monitor their activities while in action. To this aim, we have developed an algorithm that combines both features extracted from the signal of a triaxial accelerometer and one ECG lead. Microprocessors integrated in the garments detect the signal magnitude area of inertial acceleration, step frequency, trunk inclination, heart rate (HR), and HR trend in real time. Given these inputs, a classifier assigns these signals to nine classes differentiating between certain physical activities (walking, running, moving on site), intensities (intense, mild, or at rest) and postures (lying down, standing up). Specific classes will be identified as dangerous to the rescuer during operation, such as, ¿subject motionless lying down¿ or ¿subject resting with abnormal HR.¿ Laboratory tests were carried out on seven healthy adult subjects with the collection of over 4.5 h of data. The results were very positive, achieving an overall classification accuracy of 88.8%.

Wearable system-on-a-chip UWB radar for contact-less cardiopulmonary monitoring: present status.

The present status of the project aimed at the realization of an innovative wearable system-on-chip UWB radar for the cardiopulmonary monitoring is presented. The overall system consists of a wearable wireless interface including a fully integrated UWB radar for the detection of the heart beat and breath rates, and a IEEE 802.15.4 ZigBee low-power radio interface. The principle of operation of the UWB radar for the monitoring of the heart wall is summarized. With respect to the prior art, this paper reports the results of the experimental characterization of the intra-body channel loss, which has been carried out successfully in order to validate the theoretical model employed for the radar system analysis. Moreover, the main building blocks of the radar have been manufactured in 90 nm CMOS technology by ST-Microelectronics and the relevant performance are resulted in excellent agreement with those expected by post-layout simulations.

Assessment of bioinspired models for pattern recognition in biomimetic systems.

The increasing complexity of the artificial implementations of biological systems, such as the so-called electronic noses (e-noses) and tongues (e-tongues), poses issues in sensory feature extraction and fusion, drift compensation and pattern recognition, especially when high reliability is required. In particular, in order to achieve effective results, the pattern recognition system must be carefully designed. In order to investigate a novel biomimetic approach for the pattern recognition module of such systems, the classification capabilities of an artificial model inspired by the mammalian cortex, a cortical-based artificial neural network (CANN), are compared with several artificial neural networks present in the e-nose and e-tongue literature, a multilayer perceptron (MLP), a Kohonen self-organizing map (KSOM) and a fuzzy Kohonen self-organizing map (FKSOM). Each network was tested with large datasets coming from a conducting polymer-sensor-based e-nose and a composite array-based e-tongue. The comparison of results showed that the CANN model is able to strongly enhance the performances of both systems.

Wearable microwave radiometers for remote fire detection: System-on-Chip (SoC) design and proof of the concept.

The paper reports the present status of the project aimed at the realization of a wearable low-cost low-power System-on-Chip (SoC) 13-GHz passive microwave radiometer in CMOS 90 nm technology. This sensor has been thought to be inserted into the firemen jacket in order to help them in the detection of a hidden fire behind a door or a wall, especially where the IR technology fail. With respect of the prior art, the SoC is further developed and a proof of the concept is provided by means of a discrete-component prototype.

Wearable system-on-a-chip radiometer for remote temperature sensing and its application to the safeguard of emergency operators.

The remote sensing and the detection of events that may represent a danger for human beings have become more and more important thanks to the latest advances of the technology. A microwave radiometer is a sensor capable to detect a fire or an abnormal increase of the internal temperature of the human body (hyperthermia), or an onset of a cancer, or even meteorological phenomena (forest fires, pollution release, ice formation on road pavement). In this paper, the overview of a wearable low-cost low-power system-on-a-chip (SoaC) 13 GHz passive microwave radiometer in CMOS 90 nm technology is presented. In particular, we focused on its application to the fire detection for civil safeguard. In detail, this sensor has been thought to be inserted into the fireman jacket in order to help the fireman in the detection of a hidden fire behind a door or a wall. The simulation results obtained by Ptolemy system simulation have confirmed the feasibility of such a SoaC microwave radiometer in a low-cost standard silicon technology for temperature remote sensing and, in particular, for its application to the safeguard of emergency operators.

Performance analysis and early validation of a bi-modal ultrasound transducer.

In this paper we report on results from experiments performed on a bi-modal piezoelectric transducer used both as an active ultrasound transceiver and a passive acoustic sensor. The transducer, which has a low Q factor in order to exhibit a sufficiently broad bandwidth, will be integrated into a wearable system. In particular, it is placed, along with ECG fabric electrodes, within a textile belt wrapped around the chest. The transducer behaves as an acoustic sensor at low frequency and as an ultrasound transducer at high frequency. The low-frequency acoustic signals were compared with the analogue signals acquired simultaneously by commercial biomedical sensors. These signals provide information about the respiratory activity and heart apex pulse. A comparative analysis was performed both in the time and frequency domain and results were discussed. Moreover, the same transducer used at high frequencies is able to generate ultrasound signals which can bounce off the target organ, the heart, and receive the back-propagated echoes. The experimental validation was done by means of a comparison between the spatial interval inferred from time delay of the return echoes detected by the transducer and the actual distance from the target. This information, in addition to ECG signals, can provide helpful cues for the cardiac status of the subject, both in terms of prevention and diagnosis.

Multichannel techniques for motion artifacts removal from electrocardiographic signals.

Electrocardiographic (ECG) signals are affected by several kinds of artifacts, that may hide vital signs of interest. Motion artifacts, due to the motion of the electrodes in relation to patient skin, are particularly frequent in bioelectrical signals acquired by wearable systems. In this paper we propose different approaches in order to get rid of motion confounds. The first approach we follow starts from measuring electrode motion provided by an accelerometer placed on the electrode and use this measurement in an adaptive filtering system to remove the noise present in the ECG. The second approach is based on independent component analysis methods applied to multichannel ECG recordings; we propose to use both instantaneous model and a frequency domain implementation of the convolutive model that accounts for different paths of the source signals to the electrodes.

Textile sensing interfaces for cardiopulmonary signs monitoring.

A wearable system able to monitor cardiopulmonary vital signs is presented. The innovative technological core of the system is based on the use of a textile conformable sensing cloth, where conducting and piezoresistive materials are integrated in form of fibres and yarns, giving rise to fabric sensors, electrodes and connections. Electrocardiogram and impedance pneumography signals are acquired through the same textile electrodes, while to discriminate between abdominal and thoracic activity, two piezoresistive fabric sensors are placed below the lower end of the sternum and at the level of the navel for recording the thorax and the abdominal pattern of breathing. The use of impedance pneumography methodology reduces the artefacts due to the movement, phonation and rib cage expansions disjointed from respiratory mechanics. All the signals are acquired simultaneously allowing a comparative control of the cardiopulmonary activity and artefacts rejection.

a new fiber-optic liquid crystal catheter for oxygen saturation and blood flow measurements in the coronary sinus.

A new catheter for oxygen saturation and thermodilution measurements in the coronary sinus is described. The distinctive feature of this catheter is a new cholesteric liquid crystal (CLC) temperature sensor. Described in brief are the constructive and performance characteristics of the sensor, which permits temperature measurement by means of luminous pulses transmitted through optical fibres. The advantages of this solution are pointed out in terms of patient safety and instrumental integration of the thermodilution and oxygen saturation measurements both achieved through reflection photometry via optical fibres. Two possible configurations of the new catheter, with a double or a single optical connector, are illustrated and the instruments designed to be used with each catheter, are also described. Preliminary animal experiments on the application of the new catheter for the study of the coronary circulation are finally reported.

Characterization of IgG Langmuir-Blodgett films immobilized on functionalized polymers.

The bioactivity of anti-human IgG Langmuir-Blodgett (LB) films, the non-specific adsorption of protein and the topography of anti-IgG LB films have been studied for application in immunosensors. The antibody (AB) LB films were horizontally deposited on glass and functionalized polymers, such as carboxy-poly(vinyl chloride) (PVC-COOH), chloropropyl and aminopropyl sol-gel. The LB films were characterized by means of ellipsometry, atomic force microscopy (AFM) and bicinchoninic acid (BCA) protein test. The interpretation of ellipsometric data was performed using a one-layer model. Non-specifically adsorbed protein was desorbed by washing the IgG film in 0.5 M NaCl, 2 M NaCl and 1% N-cetyl-N,N,N-trimethylammoniumbromide detergent solution resulting in a 50% reduction of the film thickness. The mean thickness of an anti-IgG film on glass measured by ellipsometry, PVC-COOH and aminopropyl sol-gel was 9+/-2, 11+/-1 and 23+/-8 nm, respectively. According to the BCA test 6-8 mug antibody (AB) per slide was bound to the functionalized polymers, but only 3 mug AB per slide was adsorbed on glass. The average distance of anti-IgG granules as indicated by AFM measurements on PVC-COOH, chloropropyl and aminopropyl sol-gel was 42+/-20, 34+/-3 and 23+/-4 nm. The average distance of granular AB structures on glass, however, was 150+/-50 nm.