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Category: biological – Page 174

Giant electrochemical actuation in a nanoporous silicon-polypyrrole hybrid material

The absence of piezoelectricity in silicon makes direct electromechanical applications of this mainstream semiconductor impossible. Integrated electrical control of the silicon mechanics, however, would open up new perspectives for on-chip actuorics. Here, we combine wafer-scale nanoporosity in single-crystalline silicon with polymerization of an artificial muscle material inside pore space to synthesize a composite that shows macroscopic electrostrain in aqueous electrolyte. The voltage-strain coupling is three orders of magnitude larger than the best-performing ceramics in terms of piezoelectric actuation. We trace this huge electroactuation to the concerted action of 100 billions of nanopores per square centimeter cross section and to potential-dependent pressures of up to 150 atmospheres at the single-pore scale. The exceptionally small operation voltages (0.4 to 0.9 volts), along with the sustainable and biocompatible base materials, make this hybrid promising for bioactuator applications.

An electrochemical change in the oxidation state of polypyrrole (PPy) can increase or decrease the number of delocalized charges in its polymer backbone (1). Immersed in an electrolyte, this is also accompanied by a reversible counter-ion uptake or expulsion and thus with a marcroscopic contraction or swelling under electrical potential control, making PPy one of the most used artificial muscle materials (1–5).

Here, we combine this actuator polymer with the three-dimensional (3D) scaffold structure of nanoporous silicon (6–8) to design, similarly as found in many multiscale biological composites in nature (9), a material with embedded electrochemical actuation that consists of a few light and abundant elemental constituents (i.e., H, C, N, O, Si, and Cl).

A New Chemical ‘Tree of The Origins of Life’ Reveals Our Possible Molecular Evolution

One of the greatest mysteries in our Universe is right here on our own doorstep. No, closer — it’s in every fibre of our being.

At least 3.7 billion years ago, a few simple molecules worked together to create something new. Then a few more. And, somehow, these snowballing combinations eventually produced the first very basic living organisms that would evolve and branch out to become all life on Earth.

We don’t know the order it happened in; heck, we don’t even know when or where it happened. But new research is showing us the possibilities.

DARPA’s SIGMA Program Transitions to Protect Major U.S. Metropolitan Region

On a blustery winter day last December, a car carrying radioactive material approached one of the Port Authority of New York and New Jersey’s major transportation hubs. As the car got closer, an alarm flashed and sounded on a large monitor in the police operations center, identifying on a digital map the exact location of the vehicle and the specific radioactive isotope radiating from the car – Cesium-137. Within minutes, officers in the Port Authority Police Department – equipped with vehicle-mounted and pocket-sized radiation sensors displaying the same real-time digital map – tracked the vehicle and apprehended the suspects in a parking lot. Thankfully, the potential terrorists and radiation-emitting isotope were not a threat, as the scenario was only a drill.

The December exercise marked the capstone for DARPA’s SIGMA program, culminating a five-year effort to develop and deploy an automated, high-performance, networked radiation detection capability for counterterrorism and continuous city-to-region scale radiological and nuclear threat monitoring. The transition of the radiation-detection system took place prior to the coronavirus disease (COVID-19) pandemic. In the eight months since the SIGMA transition, DARPA has been developing and testing additional sensors under its SIGMA+ effort to detect chemical, biological and explosive threats as well.

“We want to thank the Port Authority for their outstanding support throughout the SIGMA program and their continued support as we test SIGMA+ sensors,” said Mark Wrobel, DARPA program manager in the Defense Sciences Office. “Being able to test and refine the system in the country’s largest metropolitan region was invaluable in taking SIGMA from a research project to an operationally deployed system in just five years.”

Synthetic biology brings the hard science of engineering to the basics of life

Synthetic biology startups raised some $3 billion through the first half of 2020, up from $1.9 billion for all of 2019, as the field brings the science of engineering to the art of life.

The big picture: Synthetic biologists are gradually learning how to program the code of life the way that computer experts have learned to program machines. If they can succeed — and if the public accepts their work — synthetic biology stands to fundamentally transform how we live.

What’s happening: SynBioBeta, synthetic biology’s major commercial conference, launched on Tuesday, virtually bringing together thousands of scientists, entrepreneurs, VCs and more to discuss the state of the field.

Mutations that affect aging: More common than we thought?

The number of mutations that can contribute to aging may be significantly higher than previously believed, according to new research on fruit flies. The study by scientists at Linköping University, Sweden, supports a new theory about the type of mutation that can lie behind aging. The results have been published in BMC Biology.

We live, we age and we die. Many functions of our bodies deteriorate slowly but surely as we age, and eventually an organism dies. This thought may not be very encouraging, but most of us have probably accepted that this is the fate of all living creatures—death is part of life. However, those who study find it far from clear why this is the case.

“The evolution of aging is, in a manner of speaking, a paradox. Evolution causes continuous adaptation in organisms, but even so it has not resulted in them ceasing to age,” says Urban Friberg, senior lecturer in the Department of Physics, Chemistry and Biology at Linköping University and leader of the study.

Light-based ‘tractor beam’ assembles materials at the nanoscale

Modern construction is a precision endeavor. Builders must use components manufactured to meet specific standards — such as beams of a desired composition or rivets of a specific size. The building industry relies on manufacturers to create these components reliably and reproducibly in order to construct secure bridges and sound skyscrapers.

Now imagine construction at a smaller scale — less than 1/100th the thickness of a piece of paper. This is the nanoscale. It is the scale at which scientists are working to develop potentially groundbreaking technologies in fields like quantum computing. It is also a scale where traditional fabrication methods simply will not work. Our standard tools, even miniaturized, are too bulky and too corrosive to reproducibly manufacture components at the nanoscale.

Researchers at the University of Washington have developed a method that could make reproducible manufacturing at the nanoscale possible. The team adapted a light-based technology employed widely in biology — known as optical traps or optical tweezers — to operate in a water-free liquid environment of carbon-rich organic solvents, thereby enabling new potential applications.