How to Repair Severe Spinal Cord Injuries

Northwestern University researchers have developed a new injectable therapy that harnessesdancing molecules” to reverse paralysis and repair tissue after severe spinal cord injuries. In a new study, researchers administered a single injection to tissues surrounding the spinal cords of paralyzed mice. Just four weeks later, the animals regained the ability to walk.

By sending bioactive signals to trigger cells to repair and regenerate, the breakthrough therapy dramatically improved severely injured spinal cords in five key ways: (1) The severed extensions of neurons, called axons, regenerated; (2) scar tissue, which can create a physical barrier to regeneration and repair, significantly diminished; (3) myelin, the insulating layer of axons that is important in transmitting electrical signals efficiently, reformed around cells; (4) functional blood vessels formed to deliver nutrients to cells at the injury site; and (5) more motor neurons survived. After the therapy performs its function, the materials biodegrade into nutrients for the cells within 12 weeks and then completely disappear from the body without noticeable side effects.

 

A new injectable therapy forms nanofibers with two different bioactive signals (green and orange) that communicate with cells to initiate repair of the injured spinal cord.

Our research aims to find a therapy that can prevent individuals from becoming paralyzed after major trauma or disease,” said Northwestern’s Samuel I. Stupp, who led the study. “For decades, this has remained a major challenge for scientists because our body’s central nervous system, which includes the brain and spinal cord, does not have any significant capacity to repair itself after injury or after the onset of a degenerative disease. We are going straight to the FDA to start the process of getting this new therapy approved for use in human patients, who currently have very few treatment options.”

Stupp is Board of Trustees Professor of Materials Science and Engineering, Chemistry, Medicine and Biomedical Engineering at Northwestern, where he is founding director of the Simpson Querrey Institute for BioNanotechnology (SQI) and its affiliated research center, the Center for Regenerative Nanomedicine.

The research has been published in the journal Science. The study is now available online.

Source: https://news.northwestern.edu/

How To Create a Spectrum of Natural-looking Hair Colors

We’ve long been warned of the risks of dyeing hair at home and in salons. Products used can cause allergies and skin irritation — an estimated one percent of people have an allergy to dye. Furthermore, repeated use of some dyes has been linked to cancer. But there soon may be a solution for the growing list of salons and hair color enthusiasts searching for natural alternatives to dyes and cosmetics.

Northwestern University researchers have developed a new way to create a spectrum of natural-looking hair colors, ranging from blond to black, by using enzymes to catalyze synthetic melaninMelanin is an enigmatic and ubiquitous material often found in the form of brown or black pigment. Northwestern’s Nathan Gianneschi, the research lead and associate director for the International Institute for Nanotechnology, said every type of organism produces melanin, making it a readily available and versatile material to use in the lab.

Synthetic melanin can create colors ranging from blond to black

In humans, it’s in the back of our eye to help with vision, it’s in our skin to help with protecting skin cells from UV damage,” Gianneschi said. “But birds also use it as a spectacular color display — peacock feathers are made of melanin entirely.”

Gianneschi is Professor of Chemistry in Northwestern’s Weinberg College of Arts and Sciences and a professor of materials science and engineering and biomedical engineering in Northwestern Engineering. Claudia Battistella, a postdoctoral fellow in Gianneschi’s lab, is the paper’s first author.

The research was published in the journal Chemistry of Materials.

Source: https://www.mccormick.northwestern.edu/

Electrified Tattoos and Personalized Biosensors

Electrical engineers at Duke University have devised a fully print-in-place technique for electronics that is gentle enough to work on delicate surfaces including paper and human skin. The advance could enable technologies such as high-adhesion, embedded electronic tattoos and bandages tricked out with patient-specific biosensors.

Two electronically active leads directly printed along the underside of Duke graduate student Nick Williams’s pinky successfully light up an LED when a voltage is applied

When people hear the term ‘printed electronics,’ the expectation is that a person loads a substrate and the designs for an electronic circuit into a printer and, some reasonable time later, removes a fully functional electronic circuit,” said Aaron Franklin, Associate Professor at Duke.

“Over the years there have been a slew of research papers promising these kinds of ‘fully printed electronics,’ but the reality is that the process actually involves taking the sample out multiple times to bake it, wash it or spin-coat materials onto it,” Franklin said. “Ours is the first where the reality matches the public perception.

The concept of so-called electronic tattoos were first developed in the late 2000s at the University of Illinois by John A. Rogers, who is now Professor of Materials Science and Engineering at Northwestern University. Rather than a true tattoo that is injected permanently into the skin, Rogers’s electronic tattoos are thin, flexible patches of rubber that contain equally flexible electrical components.

The thin film sticks to skin much like a temporary tattoo, and early versions of the flexible electronics were made to contain heart and brain activity monitors and muscle stimulators. While these types of devices are on their way to commercialization and large-scale manufacturing, there are some arenas in which they’re not well suited, such as when direct modification of a surface by adding custom electronics is needed. “For direct or additive printing to ever really be useful, you’re going to need to be able to print the entirety of whatever you’re printing in one step,” said Franklin. “Some of the more exotic applications include intimately connected electronic tattoos that could be used for biological tagging or unique detection mechanisms, rapid prototyping for on-the-fly custom electronics, and paper-based diagnostics that could be integrated readily into customized bandages.”

The techniques are described in a series of papers published in the journal Nanoscale and in the journal ACS Nano.

Source: https://pratt.duke.edu/

Self-Healing Coating Protects Metals From Corrosion

It’s hard to believe that a tiny crack could take down a gigantic metal structure. But sometimes bridges collapse, pipelines rupture and fuselages detach from airplanes due to hard-to-detect corrosion in tiny cracks, scratches and dents. A Northwestern University team has developed a new coating strategy for metal that self-heals within seconds when scratched, scraped or cracked. The novel material could prevent these tiny defects from turning into localized corrosion, which can cause major structures to fail.

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Localized corrosion is extremely dangerous,” said Jiaxing Huang, who led the research. “It is hard to prevent, hard to predict and hard to detect, but it can lead to catastrophic failure.” Huang is a professor of materials science and engineering in Northwestern’s McCormick School of Engineering.

When damaged by scratches and cracks, Huang’s patent-pending system readily flows and reconnects to rapidly heal right before the eyes. The researchers demonstrated that the material can heal repeatedly — even after scratching the exact same spot nearly 200 times in a row.While a few self-healing coatings already exist, those systems typically work for nanometer- to micron-sized damages. To develop a coating that can heal larger scratches in the millimeter-scale, Huang and his team looked to fluid. “When a boat cuts through water, the water goes right back together,” Huang said. “The ‘cut’ quickly heals because water flows readily. We were inspired to realize that fluids, such as oils, are the ultimate self-healing system.” But common oils flows too readily, Huang noted. So he and his team needed to develop a system with contradicting properties: fluidic enough to flow automatically but not so fluidic that it drips off the metal’s surface.

The team met the challenge by creating a network of lightweight particles — in this case graphene capsules — to thicken the oil. The network fixes the oil coating, keeping it from dripping. But when the network is damaged by a crack or scratch, it releases the oil to flow readily and reconnect. Huang said the material can be made with any hollow, lightweight particlenot just graphene. “The particles essentially immobilize the oil film,” Huang said. “So it stays in place.”

The study was published  in Research, the first Science Partner Journal recently launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST).

Source: https://news.northwestern.edu/

Megalibrary To Boost Discovery of New Materials

Different eras of civilization are defined by the discovery of new materials, as new materials drive new capabilities. And yet, identifying the best material for a given application—catalysts, light-harvesting structures, biodiagnostic labels, pharmaceuticals and electronic devices—is traditionally a slow and daunting task. The options are nearly infinite, particularly at the nanoscale (a nanometer is one-billionth of a meter) where material propertiesoptical, structural, electrical, mechanical and chemical—can significantly change, even at a fixed composition.

A new study published this week in the Proceedings of the National Academy of Sciences (PNAS) supports the efficacy of a potentially revolutionary new tool developed at Northwestern University to rapidly test millions (even billions) of nanoparticles to determine the best for a specific use.

Laser-induced heating of nanoparticles on micropillars for carbon nanotube growth

When utilizing traditional methods to identify new materials, we have barely scratched the surface of what is possible,” said Northwestern’s Chad A. Mirkin, the study’s corresponding author and a world leader in nanotechnology research and its applications. “This research provides proof-of-concept—that this powerful approach to discovery science works.”

The novel tool utilizes a combinatorial library, or megalibrary, of nanoparticles in a very controlled way. (A combinatorial library is a collection of systematically varied structures encoded at specific sites on a surface). The libraries are created using Mirkin’s Polymer Pen Lithography (PPL) technique, which relies on arrays (sets of data elements) with hundreds of thousands of pyramidal tips to deposit individual polymerdots” of various sizes and composition, each loaded with different metal salts of interest, onto a surface. Once heated, these dots are reduced to metal atoms forming a single nanoparticle at fixed composition and size.

By going small, we create two advantages in high throughput materials discovery,” said Mirkin, the executive director of Northwestern’s International Institute for Nanotechnology (IIN). “First, we can pack millions of features into square-centimeter areas, creating a path for making the largest and most complex libraries, to date. Second, by working at the sub-100 nanometer-length scale, size can become a library parameter, and much of the action, for example, in the field of catalysis, is on this length scale.”

Source: https://news.northwestern.edu/