(Press-News.org) CAMBRIDGE, Mass.--Researchers at MIT have developed a family of materials that can emit light of precisely controlled colors -- even pure white light -- and whose output can be tuned to respond to a wide variety of external conditions. The materials could find a variety of uses in detecting chemical and biological compounds, or mechanical and thermal conditions.
The material, a metallic polymer gel made using rare-earth elements, is described in a paper in the Journal of the American Chemical Society by assistant professor of materials science and engineering Niels Holten-Andersen, postdoc Pangkuan Chen, and graduate students Qiaochu Li and Scott Grindy.
The material, a light-emitting lanthanide metallogel, can be chemically tuned to emit light in response to chemical, mechanical, or thermal stimuli -- potentially providing a visible output to indicate the presence of a particular substance or condition.
The new material is an example of work with biologically inspired materials, Holten-Andersen explains. "My niche is biomimetics -- using nature's tricks to design bio-inspired polymers," he says. There are an amazing variety of "really funky" organisms in the oceans, he says, adding: "We've barely scratched the surface of trying to understand how they're put together, from a chemical and mechanical standpoint."
Studying such natural materials, evolved over millions of years to adapt to challenging environmental conditions, "allows us as engineers to derive design principles" that can be applied to other kinds of materials, he adds.
Holten-Andersen's own research has examined a particular kind of crosslinking in the threads mussels use to anchor themselves to rocks, called metal-coordination bonds. These bonds, he adds, also play an important role in many biological functions, such as binding oxygen to hemoglobin in red blood cells.
He emphasizes that the idea is not to copy nature, but to understand and apply some of the underlying principles of natural materials; in some cases, these principles can be applied in materials that are simpler in structure and easier to produce than their natural counterparts.
In this case, the use of a metal from the lanthanide group, also known as rare-earth elements, combined with a widely used polymer called polyethylene glycol, or PEG, results in a material that produces tunable, multicolored light emissions. The light emission can then reflect very subtle changes in the environment, providing a color-coded output that reveals details of those conditions.
"It's super-sensitive to external parameters," Holten-Andersen says. "Whatever you do will change the bond dynamics, which will change the color."
So, for example, the materials could be engineered to detect specific pollutants, toxins, or pathogens, with the results instantly visible just through color emission.
The materials can also detect mechanical changes, and could be used to detect stresses in mechanical systems, Holten-Andersen says. For example, it's difficult to measure forces in fluids, he says, but this approach could provide a sensitive means of doing so.
The material can be made in a gel, a thin film, or a coating that could be applied to structures, potentially indicating the development of a failure before it happens.
Metal-coordination bonds in polymers have been the subject of other work by Holten-Andersen: In a separate paper he published Aug. 31 in the journal Nature Materials, he reported making polymers with tunable mechanical properties, including stiffness. These materials are naturally self-assembling and self-healing, he says, and could be useful as energy-absorbing materials or in biological implants that need to be able to absorb impacts without breaking, he says.
This work was supported by the MIT Energy Initiative and the MIT Sea Grant via the Doherty Professorship in Ocean Utilization.
A sophisticated imaging technique has allowed scientists to virtually peer inside a 10-million-year-old sea urchin, uncovering a treasure trove of hidden fossils.
The international team of researchers from the United Kingdom, Spain and Germany, including Dr Imran Rahman from the University of Bristol, studied the exceptional specimen with the aid of state-of-the-art X-ray computed tomography (CT).
Their results show that the sea urchin fossil was riddled with borings made by shelled invertebrates called bivalves.
These fossilized boring bivalves were preserved inside ...
WASHINGTON, DC (September 3, 2015)-- The District of Columbia's needle exchange program prevented 120 new cases of HIV infection and saved an estimated $44 million over just a two-year period, according to a first-of-a-kind study published today by researchers at the Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University.
"Our study adds to the evidence that needle exchange programs not only work but are cost-effective investments in the battle against HIV," says Monica S. Ruiz, PhD, MPH, an assistant research professor in ...
Voriconazole, a prescription drug commonly used to treat fungal infections in lung transplant recipients, significantly increases the risk for skin cancer and even death, according to a new study by UC San Francisco researchers. The team recommends physicians consider patient-specific factors that could modify the drug's risks and benefits, when providing care.
Their study appears online Sept. 3, 2015, in the American Journal of Transplantation.
"It is important for physicians to be aware of the impact of voriconazole on these outcomes," said senior author Sarah Arron, ...
WASHINGTON -- Children with broken bones or joint dislocations in northern Israel emergency departments received equal pain treatment, regardless of their ethnicity or the ethnicity of the nurses who treated them, even during a period of armed conflict between the two ethnic groups. An investigation of potential disparities in pediatric emergency department pain relief in northern Israel was published online today in Annals of Emergency Medicine (""Emergency Department Pain Management in Pediatric Patients with Fracture or Dislocation in a Bi-Ethnic Population").
SAN FRANCISCO -- Black students in schools with more black teachers have more positive attitudes and higher perceptions of fairness in school discipline, according to a new study that includes a University of Kansas researcher.
The study also found white students who attend schools with a higher number of minority teachers are more likely to believe discipline from school officials is fair as well.
"Increasing the proportion of minority teachers in a school enhances all students' perceptions of school discipline fairness," said Don Haider-Markel, professor and chair ...
Imagine 12 patients who need new kidneys, and six kidneys available. How would you allocate them? New research by Rutgers social psychologists suggests your answer would depend on how the patients and their situations are presented to you.
In research recently published in Psychological Science, a journal of the Association for Psychological Science, Gretchen Chapman and Jeff DeWitt of Rutgers and Helen Colby of the University of California-Los Angeles found that people make dramatically different decisions about who should receive a transplant depending on whether the ...
As animal architects go, the average termite doesn't have many tools at their disposal - just their bodies, soil and saliva. And as guidance, variations in wind speed and direction and daily fluctuations in temperature as the sun rises and sets.
Despite such limitations, the tiny insects have managed build structures that are efficiently ventilated - a challenge that human architects still struggle with.
Led by L. Mahadevan, Lola England de Valpine Professor of Applied Mathematics, of Organismic and Evolutionary Biology, and of Physics, a team of researchers that ...
RIVERSIDE, Calif. -- Advance supply signals, such as financial health and production viability, contain rich information on supplier conditions. When and how these signals should be used is critical for improving firms' forecast and profitability.
A recent paper, "Dynamic Supply Risk Management with Signal-Based Forecast, Multi-Sourcing, and Discretionary Selling," provides mathematical tools and management principles on this issue.
The authors, Long Gao (from University of California, Riverside School of Business Administration), Nan Yang and Renyu Zhang (both from ...
Scientists have pinpointed a population of neurons in the brain that influences whether one drink leads to two, which could ultimately lead to a cure for alcoholism and other addictions.
A study, published in the Journal of Neuroscience by researchers at the Texas A&M Health Science Center College of Medicine, finds that alcohol consumption alters the structure and function of neurons in the dorsomedial striatum, a part of the brain known to be important in goal-driven behaviors. The findings could be an important step toward creation of a drug to combat alcoholism. ...
New research indicates that household food insecurity dramatically increases the likelihood of metabolic diseases in children, with many showing chronic disease markers before they graduate from high school. The study published today in the Journal of the American Osteopathic Association.
Food insecurity, defined as lacking access to food for an active, healthy life, is a preventable health threat. Yet, lack of basic access to food affects 14.3 percent of all U.S.
households and 19.5 percent of households with children.
"This is a looming health issue for the nation. ...