An international team of researchers developed a novel technique to produce precise, high-performing biometric sensors — ScienceDaily

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Wearable sensors are evolving from watches and electrodes to bendable devices that provide far more precise biometric measurements and comfort for users. Now, an international team of researchers has taken the evolution one step further by printing sensors directly on human skin without the use of heat.

Led by Huanyu “Larry” Cheng, Dorothy Quiggle Career Development Professor in the Penn State Department of Engineering Science and Mechanics, the team published their results in ACS Applied Materials & Interfaces.

“In this article, we report a simple yet universally applicable fabrication technique with the use of a novel sintering aid layer to enable direct printing for on-body sensors,” said first author Ling Zhang, a researcher in the Harbin Institute of Technology in China and in Cheng’s laboratory.

Cheng and his colleagues previously developed flexible printed circuit boards for use in wearable sensors, but printing directly on skin has been hindered by the bonding process for the metallic components in the sensor. Called sintering, this process typically requires temperatures of around 572 degrees Fahrenheit (300 degrees Celsius) to bond the sensor’s silver nanoparticles together.

“The skin surface cannot withstand such a high temperature, obviously,” Cheng said. “To get around this limitation, we proposed a sintering aid layer — something that would not hurt the skin and could help the material sinter together at a lower temperature.”

By adding a nanoparticle to the mix, the silver particles sinter at a lower temperature of about 212 F (100 C).

“That can be used to print sensors on clothing and paper, which is useful, but it’s still higher than we can stand at skin temperature,” Cheng said, who noted that about 104 F (40 C) could still burn skin tissue. “We changed the formula of the aid layer, changed the printing material and found that

New technique breaks through a technology roadblock that limited RNA imaging for 50 years — ScienceDaily

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University of Maryland scientists have developed a method to determine the structures of large RNA molecules at high resolution. The method overcomes a challenge that has limited 3D analysis and imaging of RNA to only small molecules and pieces of RNA for the past 50 years.

The new method, which expands the scope of nuclear magnetic resonance (NMR) spectroscopy, will enable researchers to understand the shape and structure of RNA molecules and learn how they interact with other molecules. The insights provided by this technology could lead to targeted RNA therapeutic treatments for disease. The research paper on this work was published in the journal Science Advances on October 7, 2020.

“The field of nuclear magnetic resonance spectroscopy has been stuck looking at things that are small, say 35 RNA building blocks or nucleotides. But most of the interesting things that are biologically and medically relevant are much bigger, 100 nucleotides or more,” said Kwaku Dayie, a professor of chemistry and biochemistry at UMD and senior author of the paper. “So, being able to break down the log jam and look at things that are big is very exciting. It will allow us to peek into these molecules and see what is going on in a way we haven’t been able to do before.”

In NMR spectroscopy, scientists direct radio waves at a molecule, exciting the atoms and “lighting up” the molecule. By measuring changes in the magnetic field around the excited atoms — the nuclear magnetic resonance — scientists can reconstruct characteristics such as the shape, structure and motion of the molecule. The data this produces can then be used to generate images, much like MRI images seen in medicine.

Ordinarily, NMR signals from the many atoms in a biological molecule such as RNA overlap with each other, making

Technique could increase sensitivity of nasal swab tests up to tenfold through simple software updates — ScienceDaily

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A multidisciplinary research team at the National Institute of Standards and Technology (NIST) has developed a way to increase the sensitivity of the primary test used to detect the SARS-CoV-2 virus, which causes COVID-19. Applying their findings to computerized test equipment could improve our ability to identify people who are infected but do not exhibit symptoms.

The team’s results, published in the scientific journal Analytical and Bioanalytical Chemistry, describe a mathematical technique for perceiving comparatively faint signals in diagnostic test data that indicate the presence of the virus. These signals can escape detection when the number of viral particles found in a patient’s nasal swab test sample is low. The team’s method helps a modest signal stand out more clearly.

“Applying our technique could make the swab test up to 10 times more sensitive,” said Paul Patrone, a NIST physicist and a co-author on the team’s paper. “It could potentially spot more people who are carrying the virus but whose viral count is too low for the current test to give a positive result.”

The researchers’ findings prove that the data from a positive test, when expressed in graphical form, takes on a recognizable shape that is always the same. Just as a fingerprint identifies a person, the shape is unique to this type of test. Only the shape’s position, and importantly, its size, differ when graphed, varying with the quantity of viral particles that exist in the sample.

While it was known previously that the shape’s position could vary, the team learned that its size can vary as well. Reprogramming test equipment to recognize this shape, regardless of size or location, is the key to improving test sensitivity.

The swab test employs a lab technique called quantitative polymerase chain reaction, or qPCR, to detect the genetic material carried