Engineers at the University of California San Diego have developed a new non-invasive method to detect infections in prostheses used for amputees, as well as for knee, hip and other joint replacements. The method, which is at the proof of concept stage, consists of a simple imaging technique and an innovative material to coat the prostheses.
"Current methods to detect infection require patients to undergo burdensome imaging procedures, such as an MRI, CAT scan, or X-rays," said Ken Loh, a professor of structural engineering at the Jacobs School of Engineering at UC San Diego and the lead researcher on the project. "By contrast, our method could be easily used in a doctor's office or in the home and, potentially, provide quantitative diagnostic-relevant information about the extent and locations of the infection."
Researchers detailed their findings on Dec. 7 at the 6th Asia Pacific Workshop on Structural Health Monitoring in Hobart, Tasmania, Australia.
The imaging technique the researchers relied on is an improved version of electrical capacitance tomography--or ECT-- which measures the human tissue and prosthesis' electrical properties using safe electrical fields. An algorithm processes the measurement data to allow physicians to reconstruct a predetermined area's electrical properties to reveal the health of the tissue, bone and prosthesis. Infection causes changes in the field, which can be detected via ECT. Loh and Ph.D. student Sumit Gupta improved the algorithm to make it more accurate.
In addition, Loh and Gupta developed a thin-film sensor that could be sprayed onto a prosthesis to improve the imaging technique's ability to detect infection or other issues occurring in the tissue or prosthesis.
The film is made of a conductive polymer matrix that is sensitive to pH, as well as carbon nanotubes embedded in the matrix that increase the material's ability to conduct electricity more sensitively regardless of the pH level. Infections caused by different microorganisms often change the local pH in human cells and affect their ability to conduct electricity.
"This is a new modality of sensing that hasn't been widely used to detect infection before," Loh said.
To test their system, the researchers spray-coated a plastic rod - as a surrogate of an actual prosthesis - with the thin-film sensor and then exposed it to several solutions that changed its pH. After each exposure to a solution, the researchers used their prototype system to scan the rod to obtain electrical measurements for their ECT algorithm. The method successfully detected the location of the rod and a change in the rod's electrical properties due to changes in pH.
"The combination of these two techniques makes our method optimal and, potentially, highly sensitive to different complications related to these prostheses and implants," Loh said.
He envisions multilayered thin-film sensors coated onto prostheses where each layer can detect different signals, such as for monitoring stresses and strains of the actual prosthesis, loosening, infection and pH changes.
Next steps would include refining the measurement setup and to conduct animal testing, which is about three years out, Loh said.
Ioana Patringenaru | EurekAlert!
A first look at interstitial fluid flow in the brain
05.07.2018 | American Institute of Physics
A sentinel to watch over ocular pressure
04.07.2018 | Fraunhofer Institute for Microelectronic Circuits and Systems
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences