Currently, there is no available needle-free approach for diabetics to monitor glucose levels in the interstitial fluid. Here, we report a path-selective, non-invasive, transdermal glucose monitoring system based on a miniaturized pixel array platform (realized either by graphene-based thin-film technology, or screen-printing). The system samples glucose from the interstitial fluid via electroosmotic extraction through individual, privileged, follicular pathways in the skin, accessible via the pixels of the array. A proof of principle using mammalian skin ex vivo is demonstrated for specific and 'quantized' glucose extraction/detection via follicular pathways, and across the hypo- to hyper-glycaemic range in humans. Furthermore, the quantification of follicular and non-follicular glucose extraction fluxes is clearly shown. In vivo continuous monitoring of interstitial fluid-borne glucose with the pixel array was able to track blood sugar in healthy human subjects. This approach paves the way to clinically relevant glucose detection in diabetics without the need for invasive, finger-stick blood sampling.

Ambipolar organic field-effect transistors (OFETs) based on heterojunction active films still suffer from an imbalance in the transport of electrons and holes. This problem is related to an uncontrolled phase separation between the donor and acceptor organic semiconductors in the thin films. In this work, we have developed a concept to improve the phase separation in heterojunction transistors to enhance their ambipolar performance. This concept is based on preaggregation of the donor polymer, in this case poly(3-hexylthiophene) (P3HT), before solution mixing with the small-molecular-weight acceptor, phenyl-C61-butyric acid methyl ester (PCBM). The resulting heterojunction transistor morphology consists of self-assembled P3HT fibers embedded in a PCBM matrix, ensuring balanced mobilities reaching 0.01 cm/V s for both holes and electrons. These are the highest mobility values reported so far for ambipolar OFETs based on P3HT/PCBM blends. Preaggregation of the conjugated polymer before fabricating binary blends can be regarded as a general concept for a wider range of semiconducting systems applicable in organic electronic devices.

Used in low-cost thermal imaging, 8-to-12μm infrared micro-bolometer hybrid detectors are very demanding in terms of offset skimming and technological fluctuation compensation: typical offset values are about 100 times larger than the signal, while the fixed-pattern noise (FPN) is about 10 times larger. State-ofthe-art image sensors feature noise-equivalent temperature difference (NETD), i.e. thermal resolutions, of about 50mK.To reach such an NETD, and considering the dependency of both offset and FPN to the temperature of the focal plane, a thermo-electrical cooler (TEC) is used to prevent the temperature of the focal plane from varying either spatially and temporally.This paper presents a 640×480 17μm-pitch TEC-less IR bolometer imager that features an NETD below 50mK over a 60°C range, while keeping a low 4V power supply. It also features a figure of merit of only 400mK/ms, which reflects its ability to deliver 50mK NETD lag-free images at 60fps. Getting rid of the TEC is a key issue to spread the use of microbolomoter imagers to cost-sensitive markets (e.g. automotive) or to extend the battery life of portable devices (e.g. gun sight). Few works to achieve TEC-less capabilities have been reported to date [1][2][3][4].This circuit is based on an enhanced differential pixel read-out ( Fig. 22.8.1), which differs from the classical bolometer read-out architectures [1,2]. As with all microbolometer imagers, this circuit is based on sensitive thermistor arrays (i.e. the bolometers), processed on top of a CMOS read-out circuit (ROIC). A bolometer's resistance varies according to its temperature, which is linked to biasing, self-heating, focal-plane temperature, and scene temperature. The differences between the sensitive bolometers and a "blind", i.e. shielded or a thermalized, reference bolometer gives an image of the scene temperature. This difference is less accurate when the characteristics of the reference bolometer differ from the sensitive bolometer (i.e. polarization, duty cycle, and physical design). The read-out circuit also impacts the accuracy of the difference and its sensitivity to temperature [5]. To sum up the TEC-less characteristic implies to keep output NETD over a large thermal range, without tuning either the supplies or polarizations of the circuit. So it depends on conversion gain, mismatch, and the offset level drift. This work is an improvement on [1], for which thermal drift of NMOS and PMOS differs, except for a specific polarization point. Finding such a polarization point for each imager design makes this architecture suffer from a lack of flexibility. The presented circuit is also an improvement over [2] and [3], for which the TEC-less ability is obtained by using a temperature probe and correction tables in order to modify polarization conditions. Such an approach implies costly calibration steps and power-consuming off-chip processing.In the presented circuit, the reference is provided by a shielded bolometer with the same characteristics as the sensitive bolometer. A shielded bolom...

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