Rice University, Paris colleagues: Study of lung cells suggests nanotubes are common pollutants
Cars appear to produce carbon nanotubes, and some of the evidence has been found in human lungs.
Carbon nanotubes (the long rods) and nanoparticles (the black clumps) appear in vehicle exhaust taken from the tailpipes of cars in Paris. The image is part of a study by scientists in Paris and at Rice University to analyze carbonaceous material in the lungs of asthma patients. They found that cars are a likely source of nanotubes found in the patients.
Courtesy of Fathi Moussa/Paris-Saclay University
Rice University scientists working with colleagues in France have detected the presence of man-made carbon nanotubes in cells extracted from the airways of Parisian children under routine treatment for asthma. Further investigation found similar nanotubes in samples from the exhaust pipes of Paris vehicles and in dust gathered from various places around the city.
The researchers reported in the journal EBioMedicine this month that these samples align with what has been found elsewhere, including Rice's home city of Houston, in spider webs in India and in ice cores.
The research in no way ascribes the children's conditions to the nanotubes, said Rice chemist Lon Wilson, a corresponding author of the new paper. But the nanotubes' apparent ubiquity should be the focus of further investigation, he said.
"We know that carbon nanoparticles are found in nature," Wilson said, noting that round fullerene molecules like those discovered at Rice are commonly produced by volcanoes, forest fires and other combustion of carbon materials. "All you need is a little catalysis to make carbon nanotubes instead of fullerenes."
A car's catalytic converter, which turns toxic carbon monoxide into safer emissions, bears at least a passing resemblance to the Rice-invented high-pressure carbon monoxide, or HiPco, process to make carbon nanotubes, he said. "So it is not a big surprise, when you think about it," Wilson said.
The team led by Wilson, Fathi Moussa of Paris-Saclay University and lead author Jelena Kolosnjaj-Tabi, a graduate student at Paris-Saclay, analyzed particulate matter found in the alveolar macrophage cells (also known as dust cells) that help stop foreign materials like particles and bacteria from entering the lungs.
The researchers wrote that their results "suggest humans are routinely exposed" to carbon nanotubes. They also suggested previous studies that link the carbon content of airway macrophages and the decline of lung function should be reconsidered in light of the new findings. Moussa confirmed his lab will continue to study the impact of man-made nanotubes on health.
The cells were taken from 69 randomly selected asthma patients aged 2 to 17 who underwent routine fiber-optic bronchoscopies as part of their treatment. For ethical reasons, no cells from healthy patients were analyzed, but because nanotubes were found in all of the samples, the study led the researchers to conclude that carbon nanotubes are likely to be found in everybody.
The study notes but does not make definitive conclusions about the controversial proposition that carbon nanotube fibers may act like asbestos, a proven carcinogen. But the authors reminded that "long carbon nanotubes and large aggregates of short ones can induce a granulomatous (inflammation) reaction."
The study partially answers the question of what makes up the black material inside alveolar macrophages, the original focus of the study. The researchers found single-walled and multiwalled carbon nanotubes and amorphous carbon among the cells, as well as in samples swabbed from the tailpipes of cars in Paris and dust from various buildings in and around the city.
"The concentrations of nanotubes are so low in these samples that it's hard to believe they would cause asthma, but you never know," Wilson said. "What surprised me the most was that carbon nanotubes were the major component of the carbonaceous pollution we found in the samples."
The nanotube aggregates in the cells ranged in size from 10 to 60 nanometers in diameter and up to several hundred nanometers in length, small enough that optical microscopes would not have been able to identify them in samples from former patients. The new study used more sophisticated tools, including high-resolution transmission electron microscopy, X-ray spectroscopy, Raman spectroscopy and near-infrared fluorescence microscopy to definitively identify them in the cells and in the environmental samples.
"We collected samples from the exhaust pipes of cars in Paris as well as from busy and non-busy intersections there and found the same type of structures as in the human samples," Wilson said.
"It's kind of ironic. In our laboratory, working with carbon nanotubes, we wear facemasks to prevent exactly what we're seeing in these samples, yet everyone walking around out there in the world probably has at least a small concentration of carbon nanotubes in their lungs," he said.
The researchers also suggested that the large surface areas of nanotubes and their ability to adhere to substances may make them effective carriers for other pollutants.
The study followed one released by Rice and Baylor College of Medicine earlier this month with the similar goal of analyzing the black substance found in the lungs of smokers who died of emphysema. That study found carbon black nanoparticles that were the product of the incomplete combustion of such organic material as tobacco.
Wilson, a professor of chemistry at Rice, and Moussa, a professor of analytical chemistry at Paris-Saclay University and a clinical biologist at the Department of Biochemistry at the Hôpitaux de Paris, are co-principal investigators of the study.
Co-authors are Henri Szwarc of Paris-Saclay University; Jocelyne Just, Yacine Laoudi and Sabah Boudjemaa, physicians at the Paediatric Pulmonology and Allergy Center and the Department of Anatomo-Pathology of the Groupe hospitalier La Roche-Guyon - A. Trousseau (Hôpitaux de Paris); Rice alumnus Keith Hartman, a former graduate student in the Wilson group; and Damien Alloyeau of Paris Diderot University.
The Welch Foundation partially supported the research.
Read the abstract at http://www.
This news release can be found online at http://news.
Follow Rice News and Media Relations via Twitter @RiceUNews
Wilson Research Group: http://wilsongroup.
Wiess School of Natural Sciences: http://naturalsciences.
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.
David Ruth | EurekAlert!
Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State
NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences