Search

Electrochemical sensors are expanding rapidly over other chemical sensoring technologies because of their potential to generate precise, selective, miniaturized and cost-effective analytical devices. These features satisfy the emerging global demand for disposable testing systems at the point-of-need, where usability, portability, and price counts most, enabling to detect critical analytical evidence by anyone, any-where and at any time, without concerning about recalibration and limited shelf life. In particular a disposable electrochemical device must include a paired smart electronic interface to specifically bias the electrochemical cell, acquire signals, per-form data conversion and communicate measurements through a standard digital interface, all under severe restrictions of size and power consumption. This thesis describes the development of a novel, cost-effective, disposable, high-performance and user-friendly electrochemical sensing platform that combines the smartness of CMOS integrated circuits (ICs) with the flexibility of printed electronics. Two practical µW-range readout integrated circuit (ROIC) realizations in 65-nm and0.18-µmCMOS technologies are presented and specifically optimized for the potentiostatic biasing and amperometric read-out of electrochemical sensors. The proposed frontend architectures yield very elegant and compact CMOS implementations by reusing the dynamic properties of the sensor itself to implement continuous-time mixed electrochemical delta-sigma modulators (¿SM). The topologies include differential potentiostats to extend its range. Furthermore, low limit of detection (LOD) values can be achieved by implementing a novel cancellation mechanism of the flicker noise coming from the feedback DAC of the electrochemical ¿SM. A standard interface based onI2Cis included on-chip not only to control the extensive system configuration but also to limit the number of IC pads towards a low-cost flip-chip assembly on flexible substrates., En els últims anys s’ha produït una ràpida expansió dels sensors electroquímics en comparació amb altres tecnologies químiques de sensat gràcies al seu potencial per generar dispositius analítics precisos, selectius, miniaturitzats i econòmics. Aquestes característiques satisfan l’actual creixent demanda de sistemes de sensat d’un sol ús, on la usabilitat, la portabilitat i el preu són els factors més importants, permetent detectar evidència analítica per qualsevol persona, en qualsevol lloc i en qualsevol moment, sense limitacions en termes de calibratge o de temps de vida útil. En particular, un dispositiu electroquímic ha d’incloure una interfície electrònica intel·ligent aparellada per estimular específicament la cèl·lula electroquímica, adquirir senyals, realitzar la conversió de dades i comunicar les mesures a través d’una interfície digital estàndard, tot sota restriccions severes de mida, cost i potencia consumida. Aquesta tesi descriu el desenvolupament d’una nova plataforma de detecció electroquímica, econòmica, d’un sol ús, d’alt rendiment i fàcil d’utilitzar, que combina la intel·ligència de circuits integrats CMOS amb la flexibilitat de l’electrònica impresa. Es presenten dues realitzacions de circuits integrats de lectura en tecnologies CMOS de65-nm i 0.18-µmamb un consum de l’ordre de µW, específicament optimitzades per ala polarització potenciostàtica i la lectura amperometria de sensors electroquímics. Les interfícies proposades ofereixen implementacions CMOS molt elegants i compactes, ja que reutilitzen les propietats dinàmiques del mateix sensor per implementar moduladors Delta-Sigma (ΔΣM) mixtes en temps continu. Les topologies inclouen potenciostats diferencials per ampliar el seu rang. A més, permeten aconseguir un límit baix de detecció mitjançant la implementació d’un nou mecanisme de cancel·lació del soroll de baixa freqüència pro-vinent de la retroalimentació digital-analògic del modulador ΔΣM electroquímic. El xip inclou una interfície dig, Postprint (published version)

An apparatus and a method using no switching elements for multiplexing and reading arrays of sensors whose electrical resistance is modulated by the signals to be measured are proposed. Sensor elements are arranged in groups and columns where each column is fed with a continuous voltage waveform of different amplitude, frequency and phase characteristics which then produce current signals that are modulated by the variable resistance signals to be measured. Modulated currents are summed row-wise and collected at the read-out circuits, either by applying a constant voltage to each row of the array or by connecting a capacitor and converting these current summations into output voltage signals. The read-out circuits de-multiplex each individual sensor signal to be measured by lock-in demodulation according to the frequencies and phases employed for the stimulation of each column.

An apparatus and a method using no switching elements for multiplexing and reading arrays of sensors whose electrical resistance is modulated by the signals to be measured are proposed. Sensor elements are arranged in group and columns where each column is fed with a continuous voltage waveform of different amplitude, frequency and phase characteristics which then produce current signals that are modulated by the variable resistance signals to be measured. Modulated currents are summed row-wise and collected at the read-out circuits, either by applying a constant voltage to each row of the array or by connecting a capacitor and converting these current summations into output voltage signals. The read-out circuits de-multiplex each individual sensor signal to be measured by means of lock-in demodulation according to the frequencies and phases employed for the stimulation of each column.

An apparatus and a method using no switching elements for multiplexing and reading arrays of sensors whose electrical resistance is modulated by the signals to be measured are proposed. Sensor elements are arranged in group and columns where each column is fed with a continuous voltage waveform of different amplitude, frequency and phase characteristics which then produce current signals that are modulated by the variable resistance signals to be measured. Modulated currents are summed row-wise and collected at the read-out circuits, either by applying a constant voltage to each row of the array or by connecting a capacitor and converting these current summations into output voltage signals. The read-out circuits de-multiplex each individual sensor signal to be measured by means of lock-in demodulation according to the frequencies and phases employed for the stimulation of each column.

La presente invención se refiere a un dispositivo biosensor para la determinación de analitos, no invasivo mediante la visuaüzación de un cambio de color, y a partir de una muestra de líquido. La presente invención se enmarca en el ámbito dispositivos para la salud, control durante realización de deporte, la seguridad laboral y la industria alimentaria. [ES], The present invention relates to a biosensor device for determining analytes non-invasively by displaying a colour change and by means of a liquid sample. The invention falls within the field of devices for health, monitoring during sports practice, work safety and the food industry. [EN]

Biosensor inalámbrico, portátil y reutilizable. La presente invención se refiere a un dispositivo biosensor para la determinación de analitos, no invasivo mediante la visualización de un cambio de color, y a partir de una muestra de líquido. La presente invención se enmarca en el ámbito dispositivos para la salud, control durante realización de deporte, la seguridad laboral y la industria alimentaria.

Smart wearables, among immediate future IoT devices, are creating a huge and fast growing market that will encompass all of the next decade by merging the user with the Cloud in a easy and natural way. Biological fluids, such as sweat, tears, saliva and urine offer the possibility to access molecular-level dynamics of the body in a non-invasive way and in real time, disclosing a wide range of applications: from sports tracking to military enhancement, from healthcare to safety at work, from body hacking to augmented social interactions. The term Internet of Wearables (IoW) is coined here to describe IoT devices composed by flexible smart transducers conformed around the human body and able to communicate wirelessly. In addition the biochemical transducer, an IoW-ready sensor must include a paired electronic interface, which should implement specific stimulation/acquisition cycles while being extremely compact and drain power in the microwatts range. Development of an effective readout interface is a key element for the success of an IoW device and application. This review focuses on the latest efforts in the field of Complementary Metal–Oxide–Semiconductor (CMOS) interfaces for electrochemical sensors, and analyses them under the light of the challenges of the IoW: cost, portability, integrability and connectivity.

This paper proposes a compact switched-capacitor (SC) multi-bit flash quantizer for low-power high-resolution delta-sigma modulators (¿SMs). First, a general power model for single-loop ¿SMs is presented to show the importance of using multi-bit quantization when facing high-resolution specifications. In this context, a SC multi-bit quantizer circuit is proposed, which exhibits low-power operation, high modularity, single comparator design and compatibility with both multi-feedforward ¿SM architectures and other SC low-power circuit techniques, like clocked comparators and switched OpAmps. A practical 50-kHz 16-bit ¿SM design case is also presented., Peer Reviewed, Postprint (published version)

The determination of ethanol intoxication in whole blood samples may open the opportunity for a precise and quick point-of-measurement in the ambit of medical emergency or law enforcement. In contrast with traditional techniques based on breath sampling, direct blood measurements present greater immunity to errors specially in case of unconscious or non-collaborative patients. In this context, a portable, sensitive and easy-to-use instrument is highly desirable. In the current work we present a smartphone-based µPotentiostat which combines a novel circuital technique for sensor readout digitalization with a reusable lab-on-a-chip (LoC) concept. Such system allows both chronoamperometric and cyclic voltammetry measurements with a reduced number of electronic components on a very compact PCB (38.5 × 22.5 mm2). Power, data-link and user interface are provided in combination with a standard smartphone, enabling cost-effectiveness and reconfigurability without sacrificing precision. The readout platform discussed in this work has been coupled to a LoC for point-of-care combining Pt electrodes microfabricated on silicon substrate for electrochemical measurement and a microfluidic structure of methacrylate for fluid management. Biosensing is enabled by in situ electrodeposition of a calcium alginate hydrogel containing horseradish peroxidase (HPR) and alcohol oxidase (AOx) for selective ethanol detection. Alginate membrane electrodeposition has been here optimized for rapid generation (2 min) and to retain the cellular fraction, thus allowing the measurement in whole blood samples. The µPotentiostat features a sensitivity of 36 nA/g L−1 to ethanol concentration in blood in the 0–1.25 g;L−1 range, with a limit of quantification (LoQ) of 4.5 nA, which is a suitable response for discerning the legal, illegal, severely illegal thresholds in a 40 µL sample of blood.