Combined team of physicists and biologists build Lyme disease detector using carbon nanotube sensor

Jun 17, 2013 by Bob Yirka weblog
Combined team of physicists and biologists build Lyme disease detector using carbon nanotube sensor

(Phys.org) —A team made up of researchers from both the physics and biology departments at the University of Pennsylvania has succeeded in building a Lyme disease detector using a carbon nanotube sensor. In their paper published in the journal Biosensors and Bioelectronics, the team describes the process they used to make the device and how it works.

Lyme disease is an infection caused by several types of bacteria—generally tick-borne, the disease can cause permanent nerve damage if not detected early. Currently patients must undergo a two-stage process as part of a diagnosis. The first is called an ELISA assay—it uses antibodies and color changes to identify substances. Because it tends to sometimes produce false positives, patients must also undergo what is known as a Western blot test—a test for the specific bacteria that cause the disease. It too tends to result in the occasional false positive however, which is why researchers continue to look for a more accurate way to detect the presence of the bacteria that causes the disease.

In this new effort, the research team grew a large array of carbon nanotubes for use as sensors. Then using a new covalent-chemistry technique they developed they attached antibody proteins to the nanotubes. The antibodies attract and capture a type of protein found in the of bacteria that are the source of Lyme disease. The adhered protein causes a change in the how well the nanotube sensors are able to conduct electricity. By measuring changes in voltage, the researchers can determine if the bacteria are present in a single drop of blood.

Besides being more accurate than the current method of testing for , the new device also can give researchers a better idea of how highly concentrated the are in a patient—allowing doctors to prescribe the right amount of medicine for treatment. The nanotube based detector can also detect the presence of the bacteria much earlier than the current method, helping to prevent and other health problems.

The new sensor isn't ready to be used by doctors just yet of course, it must be put through rigorous testing first. Also, the team believes they can improve their detector by making it sensitive to just the pieces of the that are responsible for antigen bonding, instead of the whole protein.

Explore further: Experts cautious over Google nanoparticle project

More information: Mitchell B. Lerner, Jennifer Dailey, Brett R. Goldsmith, Dustin Brisson, A.T. Charlie Johnson, Detecting Lyme disease using antibody-functionalized single-walled carbon nanotube transistors, Biosensors and Bioelectronics, Volume 45, 15 July 2013, Pages 163–167. dx.doi.org/10.1016/j.bios.2013.01.035

Abstract
We examined the potential of antibody-functionalized single-walled carbon nanotube (SWNT) field-effect transistors (FETs) to use as a fast and accurate sensor for a Lyme disease antigen. Biosensors were fabricated on oxidized silicon wafers using chemical vapor deposition grown carbon nanotubes that were functionalized using diazonium salts. Attachment of Borrelia burgdorferi (Lyme) flagellar antibodies to the nanotubes was verified by atomic force microscopy and electronic measurements. A reproducible shift in the turn-off voltage of the semiconducting SWNT FETs was seen upon incubation with B. burgdorferi flagellar antigen, indicative of the nanotube FET being locally gated by the residues of flagellar protein bound to the antibody. This sensor effectively detected antigen in buffer at concentrations as low as 1 ng/ml, and the response varied strongly over a concentration range coinciding with levels of clinical interest. Generalizable binding chemistry gives this biosensing platform the potential to be expanded to monitor other relevant antigens, enabling a multiple vector sensor for Lyme disease. The speed and sensitivity of this biosensor make it an ideal candidate for development as a medical diagnostic test.

via Nanotechweb

Related Stories

New Lyme disease test improves treatment for horses, dogs

Jun 17, 2011

Romping through summer fields seems like a harmless pleasure for dogs, horses and humans alike. But just one bite from the wrong tick can rob an animal of that pastime. The bacteria Borrelia burgdorferi catch rides with c ...

Recommended for you

Nanosafety research: The quest for the gold standard

Oct 29, 2014

Empa toxicologist Harald Krug has lambasted his colleagues in the journal Angewandte Chemie. He evaluated several thousand studies on the risks associated with nanoparticles and discovered no end of shortc ...

New nanodevice to improve cancer treatment monitoring

Oct 27, 2014

In less than a minute, a miniature device developed at the University of Montreal can measure a patient's blood for methotrexate, a commonly used but potentially toxic cancer drug. Just as accurate and ten ...

Molecular beacons shine light on how cells 'crawl'

Oct 24, 2014

Adherent cells, the kind that form the architecture of all multi-cellular organisms, are mechanically engineered with precise forces that allow them to move around and stick to things. Proteins called integrin ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.