Navigation Links
Pitt-led international study identifies human enzyme that breaks down potentially toxic nanomaterials, opens door to novel drug delivery

PITTSBURGHAn international study based at the University of Pittsburgh provides the first identification of a human enzyme that can biodegrade carbon nanotubesthe superstrong materials found in products from electronics to plasticsand in laboratory tests offset the potentially damaging health effects of being exposed to the tiny components, according to findings published online in Nature Nanotechnology.

The results could open the door to the use of carbon nanotubes as a safe drug-delivery tool and also could lead to the development of a natural treatment for people exposed to nanotubes, either in the environment or the workplace, the team reported. The researchers found that carbon nanotubes degraded with the human enzyme myeloperoxidase (hMPO) did not produce the lung inflammation that intact nanotubes have been shown to cause. Furthermore, neutrophils, the white blood cells that contain and emit hMPO to kill invading microorganisms, can be directed to attack carbon nanotubes specifically.

"The successful medical application of carbon nanotubes rely on their effective breakdown in the body, but carbon nanotubes also are notoriously durable," said lead researcher Valerian Kagan, a professor and vice chair in the Department of Environmental and Occupational Health in Pitt's Graduate School of Public Health. "The ability of hMPO to biodegrade carbon nanotubes reveals that this breakdown is part of a natural inflammatory response. The next step is to develop methods for stimulating that inflammatory response and reproducing the biodegradation process inside a living organism."

Kagan and his research group led the team of more than 20 researchers from four universities along with the laboratory groups of Alexander Star, an assistant professor of chemistry in Pitt's School of Arts and Sciences, and Judith Klein-Seethharaman, an assistant professor of structural biology in Pitt's School of Medicine. Additional Pitt researchers included Yulia Tyurina, a Pitt assistant professor of environmental and occupational health in the Graduate School of Public Health, and Donna Stolz, an associate professor of cell biology and physiology in Pitt's medical school; other researchers are from Sweden's Karolinska Institute, Trinity College in Ireland, the National Institute for Occupational Safety and Health, and West Virginia University.

Carbon nanotubes are one-atom thick rolls of graphite 100,000 times smaller than a human hair yet stronger than steel. They are used to reinforce plastics, ceramics, or concrete; are excellent conductors of electricity and heat; and are sensitive chemical sensors. However, a nanotube's surface also contains thousands of atoms that could react with the human body in unknown ways. Tests on mice have shown that nanotube inhalation results in severe lung inflammation coupled with an early onset of fibrosis. The tubes' durability raises additional concern about proper disposal and cleanup. In 2008, Star and Kagan reported in Nano Letters that carbon nanotubes deteriorate when exposed to the plant enzyme horseradish peroxidase, but their research focused on cleanup after accidental spills during manufacturing or in the environment.

For the current study, the researchers focused on human MPO because it works via the release of strong acids and oxidantssimilar to the chemicals used to break down carbon nanotubes. They first incubated short, single-walled nanotubes in an hMPO and hydrogen peroxide solutionthe hydrogen peroxide sparks and sustains hMPO activityfor 24 hours, after which the structure and bulk of the tube had completely degenerated. The nanotubes degenerated even faster when sodium chloride was added to the solution to produce hypochlorite, a strong oxidizing compound known to break down nanotubes.

After establishing the effectiveness of hMPO in degrading carbon nanotubes, the team developed a technique to prompt neutrophils to attack nanotubes by capturing them and exposing them to the enzyme. They implanted a sample of nanotubes with antibodies known as immunoglobulin G (IgG), which made them specific neutrophil targets. After 12 hours, 100 percent of IgG nanotubes were degraded versus 30 percent of those without IgG. The researchers also tested the ability of macrophages, another white blood cell, to break down nanotubes, but after two days, only 50 percent of the tubes had degenerated.

In subsequent laboratory tests, lung tissue exposed to the degraded nanotubes for seven days exhibited negligible change when compared to unexposed tissue. On the other hand, tissue exposed to untreated nanotubes developed severe inflammation.


Contact: Morgan Kelly
University of Pittsburgh

Related biology news :

1. Pitt-led study identifies human enzyme that breaks down potentially toxic nanomaterials
2. Pitt-led team gets $5.6 million contract for heart assist device for infants and toddlers
3. Pitt-led researchers create quick, simple fluorescent detector for TB
4. International team of scientists describe first Cretaceous African amber deposit
5. BIO-key(R) International Taps JMR Worldwide for PR, IR and Strategic Communications
6. Smithsonian hosts 2010 International CAM Workshop in Panama
7. From international harbor to native habitat
8. UC Riverside to host 3-day international meeting on drought
9. BIO-key(R) International Biometric Accuracy Improved by More Than 23% as Reported in Recent NIST Testing
10. Leicesters internationally acclaimed genetics research involved in project into saffron production
11. BIO-key(R) International to Showcase Biometric Identification Technology at RSA Conference 2010
Post Your Comments:
(Date:10/29/2015)... Oct. 29, 2015  The J. Craig Venter Institute ... "DNA Synthesis and Biosecurity: Lessons Learned and Options for ... Health and Human Services guidance for synthetic biology providers ... --> --> Synthetic ... the potential to pose unique biosecurity threats. It now ...
(Date:10/29/2015)... October 29, 2015 NXTD ... company focused on the growing mobile commerce market ... that StackCommerce, a leading marketplace to discover and ... Wocket® smart wallet on StackSocial for this holiday ... or the "Company"), a biometric authentication company focused ...
(Date:10/27/2015)... , Oct. 27, 2015 Synaptics Inc. (NASDAQ: ... today announced that Google has adopted the Synaptics ® ... controller solutions to power its newest flagship smartphones, the ... Huawei. --> --> ... Google to provide strategic collaboration in the joint development ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... ... November 24, 2015 , ... The Academy of Model Aeronautics (AMA), ... MultiGP, also known as Multirotor Grand Prix, to represent the First–Person View (FPV) racing ... AMA members have embraced this type of racing and several new model aviation pilots ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris ... today that the remaining 11,000 post-share consolidation (or ... Warrants (the "Series B Warrants") subject to the ... on November 23, 2015, which will result in ... giving effect to the issuance of such shares, ...
(Date:11/24/2015)... ... November 24, 2015 , ... Creation ... on being named to Deloitte's 2015 Technology Fast 500 list of the fastest ... AcceleDent®, a FDA-cleared, Class II medical device that speeds up orthodontic tooth movement ...
(Date:11/24/2015)... Nev. , Nov. 24, 2015  PDL BioPharma, Inc. ... P. McLaughlin , the company,s president and chief executive officer, ... Healthcare Conference next week in New York City ... occur on Tuesday, December 1, 2015 at 9:30 a.m. EST. ... Please connect to the website at least 15 minutes prior ...
Breaking Biology Technology: