A step toward better brain implants using conducting polymer nanotubes

This illustration depicts neurons firing (green structures in the foreground) and communicating with nanotubes in the background. Credit: Illustration courtesy of Mohammad Reza Abidian

ANN ARBOR, Mich.---Brain implants that can more clearly record signals from surrounding neurons in rats have been created at the University of Michigan. The findings could eventually lead to more effective treatment of neurological disorders such as Parkinson's disease and paralysis.

Neural electrodes must work for time periods ranging from hours to years. When the electrodes are implanted, the brain first reacts to the acute injury with an inflammatory response. Then the brain settles into a wound-healing, or chronic, response.

It's during this secondary response that brain tissue starts to encapsulate the electrode, cutting it off from communication with surrounding neurons.

The new brain implants developed at U-M are coated with nanotubes made of poly(3,4-ethylenedioxythiophene) (PEDOT), a biocompatible and electrically conductive polymer that has been shown to record neural signals better than conventional metal electrodes.

U-M researchers found that PEDOT nanotubes enhanced high-quality unit activity (signal-to-noise ratio >4) about 30 percent more than the uncoated sites. They also found that based on in vivo impedance data, PEDOT nanotubes might be used as a novel method for biosensing to indicate the transition between acute and chronic responses in brain tissue.

The results are featured in the cover article of the Oct. 5 issue of the journal Advanced Materials. The paper is titled, "Interfacing Conducting Polymer Nanotubes with the Central Nervous System: Chronic Neural Recording using Poly(3-4-ethylenedioxythiophene) Nanotubes."

"Microelectrodes implanted in the brain are increasingly being used to treat neurological disorders," said Mohammad Reza Abidian, a post-doctoral researcher working with Professor Daryl Kipke in the Neural Engineering Laboratory at the U-M Department of Biomedical Engineering.

"Moreover, these electrodes enable neuroprosthetic devices, which hold the promise to return functionality to individuals with spinal cord injuries and neurodegenerative diseases. However, robust and reliable chronic application of neural electrodes remains a challenge."

In the experiment, the researchers implanted two neural microelectrodes in the brains of three rats. PEDOT nanotubes were fabricated on the surface of every other recording site by using a nanofiber templating method. Over the course of seven weeks, researchers monitored the electrical impedance of the recording sites and measured the quality of recording signals.

PEDOT nanotubes in the coating enable the electrodes to operate with less electrical resistance than current metal electrode sites, which means they can communicate more clearly with individual neurons.

"Conducting polymers are biocompatible and have both electronic and ionic conductivity," Abidian said. "Therefore, these materials are good candidates for biomedical applications such as neural interfaces, biosensors and drug delivery systems."

In the experiments, the Michigan researchers applied PEDOT nanotubes to microelectrodes provided by the U-M Center for Neural Communication Technology. The PEDOT nanotube coatings were developed in the laboratory of David C. Martin, now an adjunct professor of materials science and engineering, macromolecular science and engineering, and biomedical engineering. Martin is currently the Karl W. Böer Professor and Chair of the Materials Science and Engineering Department at the University of Delaware.

Martin is also co-founder and chief scientific officer for Biotectix, a U-M spinoff company located in Ann Arbor. The company is working to commercialize conducting polymer-based coatings for a variety of biomedical devices

In previous experiments, Abidian and his colleagues have shown that PEDOT nanotubes could carry with them drugs to prevent encapsulation.

"This study paves the way for smart recording electrodes that can deliver drugs to alleviate the immune response of encapsulation," Abidian said.

More information: Scientific article: http://www3.interscience.wiley.com/cgi-bin/fulltext/122525755/PDFSTART

Source: University of Michigan

Implantable Device Offers Continuous Cancer Monitoring

Surgical removal of a tissue sample is now the standard for diagnosing cancer. Such procedures, known as biopsies, are accurate but offer only a snapshot of the tumor at a single moment in time.
Monitoring a tumor for weeks or months after the biopsy and tracking its growth and how it responds to treatment would be much more valuable, says Michael J. Cima, Ph.D., who has developed the first implantable device that can do just that. Dr. Cima, professor of materials science and engineering at the Massachusetts Institute of Technology (MIT) and a member of the MIT-Harvard Center of Cancer Nanotechnology Excellence (CCNE), and his colleagues reported in the journal Biosensors and Bioelectronics that their device successfully tracked a tumor marker in mice for 1 month. Fellow MIT CCNE investigators Robert Langer, Ph.D., Al Charest, Ph.D., M.Sc., and Ralph Weissleder, M.D., Ph.D., also contributed to this work.
Such implants could one day provide up-to-the-minute information about what a tumor is doing—whether it is growing or shrinking, how it is responding to treatment, and whether it has metastasized or is about to do so. “What this does is basically take the lab and put it in the patient,” said Dr. Cima.
The devices, which could be implanted at the time of biopsy, also could be tailored to monitor chemotherapy agents, allowing doctors to determine whether cancer drugs are reaching the tumors. They also can be designed to measure acidity (pH) or oxygen levels, which reveal tumor metabolism and how it is responding to therapy.
The cylindrical, 5-millimeter implant is made of high-density polyethylene encased in a polycarbonate membrane with 10-nanometer-diameter pores. Magnetic nanoparticles coated with antibodies specific to the target molecules are loaded into the device. Target molecules enter the implant through the polycarbonate membrane, binding to the nanoparticles and causing them to clump together. That clumping can be detected by magnetic resonance imaging (MRI) because the aggregated nanoparticles produce a marked change in the MRI signal associated with the implanted device. The researchers observed measurable changes within 1 day of implantation.
In the published work, the investigators transplanted human tumors into test mice and then used the implants to track levels of human chorionic gonadotropin, a hormone produced by the human tumor cells. Dr. Cima said he believes an implant to test for pH levels could be commercially available in a few years, followed by devices to test for complex chemicals such as other hormones and drugs.
This work, which is detailed in the paper “Implantable diagnostic device for cancer monitoring,” was supported by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. An abstract is available at the journal’s Web site.
Provided by National Cancer Institute

Magnetic Bacteria Used as Drug Carriers

Bacteria take fantastic voyage through bloodstream

Canadian engineers have sent swimming magnetic bacteria through the bloodstreams of rats. The work is a step towards the team's goal of harnessing them as drug mules steered through human bodies using magnetic fields.

Microscopic machines have proven attractive to medics trying to make treatments ever more targeted and less invasive than surgery. But although it is now possible to make micromachines from individual molecules, providing them with power is another matter.

Propulsion systems or even swimming motions that work at larger scales don't work when scaled down because of the treacly forces that dominate fluids at microscopic scales.

Sylvain Martel's team at the École Polytechnique de Montréal in Canada think tapping the skills of bacteria that have evolved to swim with ease at the microscopic scale is the best solution.

Speed demon

"Instead of trying to build a nanomachine it makes more sense to spend effort trying to control what nature provides," says Martel. He and his team are focusing on a bacterium dubbed MC-1 – a microbial speed demon that swims 10 times faster than most species and can travel at top speeds of 200 micrometres per second using its twirling flagella.

If MC-1 was to be loaded with a drug and given the ability to target a particular tissue it could provide a nimble addition to the medical arsenal.

Apart from speed, the bacterium has another property that makes it a perfect candidate for the role: each cell contains a chain of magnetic nanoparticles, allowing the bacteria to sense and swim along magnetic fields.

Remote control

By placing a patient inside an MRI machine it would be possible to create a magnetic field to steer the magnetic bacteria in any direction, towards targets just a few micrometres across, says Martel.

Martel says initial tests suggest the bacteria are not harmful – and generally not harmed – inside the body. His team injected a 50 microlitre solution containing some 50 million MC-1 bacteria into the bloodstream of rats, and found no adverse reaction.

"More work needs to be done, but it appears a sufficient quantity of these bacteria can be injected without causing toxicity," he told New Scientist. The bacteria naturally die after about 40 minutes in the blood, and would then be cleaned up by the immune system.

The initial rat trials simply assessed the health impact of injecting the bacteria – the next step is to guide them using magnetic fields, which will be precisely controlled via computer, says Martel. The team has already shown that's possible in principle by steering the magnetic bacteria in a 50-micrometre-diameter tube system.

Metal mules

In 2007, the same team piloted metal particles through the blood stream of a living pig using an MRI machines. Using magnetic bacteria is a more attractive option because the applied field needs only to direct the microbes as they propel themselves towards the target.

Bradley Nelson at the Swiss Federal Institute of Technology in Zurich, who earlier this year designed a magnetically controlled artificial bacterium, thinks the work is an improvement on a 2004 study by Howard Berg at Harvard University.]

Berg used another bacterial species to create a simple propulsion system. "By using MC-1 instead, Martel had been able to demonstrate steering in addition to propulsion," Nelson says. "I am sure there are issues in keeping the bacteria happy, but it is certainly a clever idea."

International Journal of Robotics Research (DOI: 10.1177/0278364908100924)

Cancer Smell Used by Nanosensor Arrays for Early Detection

(PhysOrg.com) -- In 2006 researchers established that dogs could detect a cancer smell by sniffing the exhaled breath of cancer patients. Now, using nanoscale arrays of detectors, two groups of investigators have shown that a compact mechanical device also can sniff out lung cancer in humans.


 Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. 

The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. 

Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. 

Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air.  

In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. 

The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. 

Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. 

Provided by National Cancer Institute

Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air. Ads by Google $0.01 Web Hosting - Scalable, Secure Web Hosting. Try Our Award-Winning Service Now! - www.HostGator.com/1Penny In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. Provided by National Cancer Institute (news : web)

Read more at: http://phys.org/news160065741.html#jCp

Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air. Ads by Google $0.01 Web Hosting - Scalable, Secure Web Hosting. Try Our Award-Winning Service Now! - www.HostGator.com/1Penny In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. Provided by National Cancer Institute (news : web)

Read more at: http://phys.org/news160065741.html#jCp

Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air. Ads by Google $0.01 Web Hosting - Scalable, Secure Web Hosting. Try Our Award-Winning Service Now! - www.HostGator.com/1Penny In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. Provided by National Cancer Institute (news : web)

Read more at: http://phys.org/news160065741.html#jCp

Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air. Ads by Google $0.01 Web Hosting - Scalable, Secure Web Hosting. Try Our Award-Winning Service Now! - www.HostGator.com/1Penny In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. Provided by National Cancer Institute (news : web)

Read more at: http://phys.org/news160065741.html#jCp

Hossam Haick, Ph.D., and his colleagues at the Israel Institute of Technology in Haifa, used a network of 10 sets of chemically modified carbon nanotubes to create a multicomponent sensor capable of discriminating between a healthy breath and one characteristic of lung cancer patients. This work appears in the journal Nano News. Meanwhile, Silvano Dragonieri, M.D., University of Bari, Italy, and his colleagues used a commercial nanoarray-based electronic “nose” to discriminate between the breath of patients with non-small cell lung cancer and chronic obstructive pulmonary disease (COPD). These results appear in the journal Lung Cancer. The key development in Dr. Haick’s team’s work demonstrated that the electrical resistance of carbon nanotubes coated with nonpolymeric organic layers changes substantially when nonpolar organic molecules, such as those present in a breath, pass over the nanotubes. Uncoated nanotubes do not respond strongly to the type of nonpolar molecules found in the human breath. Using 10 different organic coatings, the investigators created field-effect transistors comprising random networks of each of the different coated nanotubes, and the resulting array produces a characteristic change in electrical output when exposed to volatile nonpolar organic substances. A computational technique known as principal component analysis can decipher the complex signal change produced when mixtures of nonpolar organic molecules pass over the sensor network. When plotted in two dimensions, the data from a simulated set of “healthy” and “lung cancer” patients form two clear clusters that readily distinguish the two sets of patients. The investigators also showed that their device could identify healthy rats from those with chronic kidney failure. Rather than designing their own device, Dr. Dragonieri’s group used a Cyranose 320 built by Smiths Detection based in Pasadena, California. This hand-held electronic nose, which is used widely throughout the chemical and food processing industries, employs a nanocomposite sensor array to rapidly detect volatile organic compounds in the air. Ads by Google $0.01 Web Hosting - Scalable, Secure Web Hosting. Try Our Award-Winning Service Now! - www.HostGator.com/1Penny In this study, Dr. Dragonieri’s team collected breath samples from 10 patients with NSCLC, 10 with COPD, and 10 healthy controls. After drying the samples, the investigators analyzed them using the Cyranose 320 and its onboard statistical software. Smellprints, analogous to fingerprints, from the three groups of patients were clearly distinguishable, with no ambiguity among the three groups. The investigators note that these results warrant conducting a large-scale, prospective clinical trial to determine whether this system could be useful in real clinical settings, including physician offices. The results of Dr. Haick’s team’s work appear in the paper “Detection of nonpolar molecules by means of carrier scattering in random networks of carbon nanotubes: Toward diagnosis of diseases via breath samples.” An abstract of this paper is available at the journal’s Web site. Dr. Dragnieri and his colleagues published their work in the paper “An electronic nose in the discrimination of patients with non-small cell cancer and COPD.” Investigators from the Leiden University Medical Center and the University of Amsterdam in The Netherlands, as well as from the Fondazione Salvatore Maugeri in Cassano delle Murge, Italy, contributed to this work. An abstract of this paper is available at the journal’s Web site. Provided by National Cancer Institute (news : web)

Read more at: http://phys.org/news160065741.html#jCp