Passive Impedance-Matched Neural Recording Systems for Improved Signal Sensitivity.

Wireless passive neural recording systems integrate sensory electrophysiological interfaces with a backscattering-based telemetry system. Despite the circuit simplicity and miniaturization with this topology, the high electrode-tissue impedance creates a major barrier to achieving high signal sensitivity and low telemetry power. In this paper, buffered impedance is utilized to address this limitation. The resulting passive telemetry-based wireless neural recording is implemented with thin flexible packages. Thus, the paper reports neural recording implants and integrator systems with three improved features: (1) passive high impedance matching with a simple buffer circuit, (2) a bypass capacitor to route the high frequency and improve mixer performance, and (3) system packaging with an integrated, flexible, biocompatible patch to capture the neural signal. The patch consists of a U-slot dual-band patch antenna that receives the transmitted power from the interrogator and backscatters the modulated carrier power at a different frequency. When the incoming power was 5-10 dBm, the neurosensor could communicate with the interrogator at a maximum distance of 5 cm. A biosignal as low as 80 µV peak was detected at the receiver.

Naked-eye detection strategies coupled with isothermal nucleic acid amplification techniques for the detection of human pathogens.

Nucleic acid amplification-based techniques have gained acceptance by the scientific, and general, community as reference methodologies for many different applications. Since the development of the gold standard of these techniques, polymerase chain reaction (PCR), back in the 1980s many improvements have been made, and alternative techniques emerged reporting improvements over PCR. Among these, isothermal amplification approaches resulted of particular interest as could overcome the need of specialized equipment to accurately control temperature changes, but it was after year 2000 that these techniques have flourished in a huge number of novel alternatives with many different degrees of complexities and requirements. An added value is their possibility to be combined with many different naked-eye detection strategies, simplifying the resources needed, allowing to reduce cost, and serving as the basis for novel developments of lab-on-chip systems, and miniaturized devices, for point-of-care testing. In this review, we will go over different types of naked-eye detection strategies, combined with isothermal amplification. This will provide the readers up-to-date information for them to select the most appropriate strategies depending on the particular needs and resources for their experimental setup.

Ultraminiaturized Stretchable Strain Sensors Based on Single Silicon Nanowires for Imperceptible Electronic Skins.

Miniaturized stretchable strain sensors are key components in E-skins for applications such as personalized health-monitoring, body motion perception, and human-machine interfaces. However, it remains a big challenge to fabricate miniaturized stretchable strain sensors with high imperceptibility. Here, we reported for the first time novel ultraminiaturized stretchable strain sensors based on single centimeter-long silicon nanowires (cm-SiNWs). With the diameter of the active materials even smaller than that of spider silks, these sensors are highly imperceptible. They exhibit a large strain sensing range (>45%) and a high durability (>10 000 cycles). Their optimum strain sensing ranges could be modulated by controlling the prestrains of the stretchable cm-SiNWs. On the basis of this capability, sensors with appropriate sensing ranges were chosen to respectively monitor large and subtle human motions including joint motion, swallow, and touch. The strategy of applying single cm-SiNWs in stretchable sensors would open new doors to fabricate ultraminiaturized stretchable devices.

Advanced biosensors for mycotoxin detection incorporating miniaturized meters.

Advanced biosensors, considered as emerging technologies, are capable of accurate, quantitative and real-time analysis for point-of-care testing (POCT) applications. Moreover, the integrating of miniaturized meters into these advanced biosensors makes them ideally appropriate for portable, sensitive and selective detection of biomolecules. Miniaturized meters including PGMs (personal glucose meters), thermometer, pressuremeter, pH meter, etc. are the most accurate devices and wide availability in the market, exhibiting a promising potential towards detection of small molecule mycotoxins. In this article, we introduce and analyze the recent advancements for sensing of mycotoxins measured by handheld meters since the first report in 2012. Furthermore, limitations and challenges for versatile meters application against mycotoxins in food matrix are highlighted. By overcoming the bottleneck problems, we believe the miniaturized meters-based biosensor platform will provide great possibilities for mycotoxins analysis and launch them to the market.

Miniaturized Flexible Non-Contact Interface Based on Heat Shrinkage Technology.

High-performance miniaturized flexible sensors are becoming increasingly important in wearable electronics. However, miniaturization of devices often requires high-precision manufacturing processes and equipment, which limits the commercialization of flexible sensors. Therefore, revolutionary technologies for manufacturing miniaturized flexible sensors are highly desired. In this work, a new method for manufacturing miniaturized flexible humidity sensor by utilizing heat shrinkage technology is presented. This method successfully achieves much smaller sensor and denser interdigital electrode. Utilizing this method, a miniaturized flexible humidity sensor and array are presented, fabricated by anchoring nano-Al2 O3 into carbon nano-tube as the humidity sensitive film. This heat shrinkage technology, forming wrinkle structure on the humidity sensitive film, endows the sensor with a high sensitivity over 200% (ΔR/R0 ) at humidity levels ranging from 0 to 90%RH and a fast recovery time (0.5 s). The sensor allows non-contact monitoring human respiration and alerting in case of an asthma attack and the sensor array can be adaptively attached to the wrist as a non-contact human-machine interface to control the mechanical hand or computer. This work provides a general and effective heat shrinkage technology for the development of smaller and more efficient flexible circuits and sensor devices.

Analytical Chemistry Strategies in the Use of Miniaturised NIR Instruments: An Overview.

Miniaturized NIR instruments have been increasingly used in the last years, and they have become useful tools for many applications on a broad variety of samples. This review focuses on miniaturized NIR instruments from an analytical point of view, to give an overview of the analytical strategies used in order to help the reader to set up their own analytical methods, from the sampling to the data analysis. It highlights the uses of these instruments, providing a critical discussion including current and future trends.

Emerging Designs of Electronic Devices in Biomedicine.

A long-standing goal of nanoelectronics is the development of integrated systems to be used in medicine as sensor, therapeutic, or theranostic devices. In this review, we examine the phenomena of transport and the interaction between electro-active charges and the material at the nanoscale. We then demonstrate how these mechanisms can be exploited to design and fabricate devices for applications in biomedicine and bioengineering. Specifically, we present and discuss electrochemical devices based on the interaction between ions and conductive polymers, such as organic electrochemical transistors (OFETs), electrolyte gated field-effect transistors (FETs), fin field-effect transistor (FinFETs), tunnelling field-effect transistors (TFETs), electrochemical lab-on-chips (LOCs). For these systems, we comment on their use in medicine.