Molecular electronics sensors on a scalable semiconductor chip: A platform for single-molecule measurement of binding kinetics and enzyme activity.

For nearly 50 years, the vision of using single molecules in circuits has been seen as providing the ultimate miniaturization of electronic chips. An advanced example of such a molecular electronics chip is presented here, with the important distinction that the molecular circuit elements play the role of general-purpose single-molecule sensors. The device consists of a semiconductor chip with a scalable array architecture. Each array element contains a synthetic molecular wire assembled to span nanoelectrodes in a current monitoring circuit. A central conjugation site is used to attach a single probe molecule that defines the target of the sensor. The chip digitizes the resulting picoamp-scale current-versus-time readout from each sensor element of the array at a rate of 1,000 frames per second. This provides detailed electrical signatures of the single-molecule interactions between the probe and targets present in a solution-phase test sample. This platform is used to measure the interaction kinetics of single molecules, without the use of labels, in a massively parallel fashion. To demonstrate broad applicability, examples are shown for probe molecule binding, including DNA oligos, aptamers, antibodies, and antigens, and the activity of enzymes relevant to diagnostics and sequencing, including a CRISPR/Cas enzyme binding a target DNA, and a DNA polymerase enzyme incorporating nucleotides as it copies a DNA template. All of these applications are accomplished with high sensitivity and resolution, on a manufacturable, scalable, all-electronic semiconductor chip device, thereby bringing the power of modern chips to these diverse areas of biosensing.

Cross-Border Supply Chain System Constructed by Complex Computer Blockchain for International Cooperation.

The rapid development of China's local e-commerce and the continuous improvement of its business model have not only pushed the country to the forefront of the globe but also opened up the unprecedented potential for China's cross-border e-commerce. Therefore, it is imperative to build a balanced and sustainable cross-border e-commerce system, and cross-border e-commerce on the Silk Road has become a new highlight of China's e-commerce development. This study proposes a cross-border supply chain model based on the complex computer blockchain for international cooperation scenarios, contrasts and analyzes decision making in two cross-border supply chain scenarios with and without blockchain implementation, and investigates the sufficient conditions for blockchain implementation in the cross-border supply chain from the perspective of various value objectives. The analysis reveals that the cross-border supply chain has sufficient incentive to implement blockchain when the value gain generated by implementing blockchain is high or the value gain is low but the potential market size weakening factor of cross-border products is greater than a certain degree. It demonstrates that the link between cross-border product price elasticity, manufacturer cross-border effort cost, and customer cross-border preference degree would impact the circumstances for adopting blockchain in cross-border supply chains. The model also lays out a plan for the government to improve cross-border e-commerce logistics, strengthen oversight, and create a regional financial service network system to reduce credit risk.4.

Robust Biopotential Acquisition via a Distributed Multi-Channel FM-ADC.

This contribution presents an active electrode system for biopotential acquisition using a distributed multi-channel FM-modulated analog front-end and ADC architecture. Each electrode captures one biopotential signal and converts to a frequency modulated signal using a VCO tuned to a unique frequency. Each electrode then buffers its output onto a shared analog line that aggregates all of the FM-modulated channels. This aggregation results in rugged, wearable form factor by eliminating wire clutter of traditional systems. A gateway integrated circuit then digitizes the composite FM signal and transmits for further processing. The coding gain due to bandwidth expansion of FM provides a large usable dynamic range (DR) and the single ADC for multiple channels results in significant power savings. Finally, the use of FM signals between the transducers and ADC provides resilience to motion and EMI artifacts. The system is implemented in 65 nm silicon using two distinct 1 mm 2 chip designs. Six-channel operation is demonstrated using FM channels with center frequencies around 15 MHz and the system achieves a usable DR of over 100 dB, while achieving figure of merit competitive with state of the art prior works using traditional approaches.