Wireless Electronic Implants Stop Staph, Then Harmlessly Dissolve

29 01 2015

Researchers at Tufts University, in collaboration with a team at the University of Illinois at Champaign-Urbana, have demonstrated a resorbable electronic implant that eliminated bacterial infection in mice by delivering heat to infected tissue when triggered by a remote wireless signal.  The silk and magnesium devices then harmlessly dissolved in the test animals. The technique had previously been demonstrated only in vitro. The research is published online in the Proceedings of the National Academy of Sciences Early Edition the week of November 24-28, 2014.

“This is an important demonstration step forward for the development of  on-demand medical devices that can be turned on remotely to perform a therapeutic function in a patient and then safely disappear after their use, requiring no retrieval,” said senior author Fiorenzo Omenetto, professor of biomedical engineering and Frank C. Doble professor at Tufts School of Engineering. “These wireless strategies could help manage post-surgical infection, for example, or pave the way for eventual ‘wi-fi’ drug delivery.”

Implantable medical devices typically use non-degradable materials that have limited operational lifetimes and must eventually be removed or replaced. The new wireless therapy devices are robust enough to survive mechanical handling during surgery but designed to harmlessly dissolve within minutes or weeks depending on how the silk protein was processed, noted the paper’s first author, Hu Tao, Ph.D., a former Tufts post-doctoral associate who is now on the faculty of the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences.

Each fully dissolvable wireless heating device consisted of a serpentine resistor and a power-receiving coil made of magnesium deposited onto a silk protein layer. The magnesium heater was encapsulated in a silk “pocket” that protected the electronics and controlled its dissolution time.

Devices were implanted in vivo in S. aureus infected tissue and activated by a wireless transmitter for two sets of 10-minute heat treatments. Tissue collected from the mice 24 hours after treatment showed no sign of infection, and surrounding tissues were found to be normal. Devices completely dissolved after 15 days, and magnesium levels at the implant site and surrounding areas were comparable to levels typically found in the body.

The researchers also conducted in vitro experiments in which similar remotely controlled devices released the antibiotic ampicillin to kill E. coli and S. aureus bacteria. The wireless activation of the devices was found to enhance antibiotic release without reducing antibiotic activity.

Omenetto holds an adjunct appointment in the Department of Physics in the School of Arts and Sciences at Tufts as well as appointments in the Departments of Biomedical Engineering and Chemical and Biological Engineering in the School of Engineering.

In addition to Omenetto and Tao, authors on the paper were co-first author Suk-Won Hwang, formerly of the Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology, and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, and now at KU-KIST Graduate School of Converging Science and Technology, Korea University; Benedetto Marelli, Bo An, Jodie E. Moreau, Miaomiao Yang, and Mark A. Brenckle, Department of Biomedical Engineering, Tufts University; Stanley Kim, Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology, and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign; David L. Kaplan, Department of Biomedical Engineering and Department of Chemical and Biomedical Engineering, Tufts University; and co-corresponding author John A. Rogers, Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology, Frederick Seitz Materials Research Laboratory, Department of Chemistry, and Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign.

Research reported in this paper was supported by the National Institutes of Health under award number P41-EB002520 and by the National Science Foundation under grant number DMR-1242240.

“Silk-based resorbable electronic devices for remotely controlled therapy and in vivo infection abatement,” http://www.pnas.org/cgi/doi/10.1073/pnas.1407743111

Located on Tufts’ Medford/Somerville campus, Tufts’ School of Engineering offers a rigorous engineering education in a unique environment that blends the intellectual and technological resources of a world-class research university with the strengths of a top-ranked liberal arts college. Close partnerships with Tufts’ excellent undergraduate, graduate and professional schools, coupled with a long tradition of collaboration, provide a strong platform for interdisciplinary education and scholarship. The School of Engineering’s mission  is to educate engineers committed to the innovative and ethical application of science and technology in addressing the most pressing societal needs, to develop and nurture twenty-first century leadership qualities in its students, faculty, and alumni, and to create and disseminate transformational new knowledge and technologies that further the well-being and sustainability of society in such cross-cutting areas as human health, environmental sustainability, alternative energy, and the human-technology interface.

 

 

Now.tufts.edu [en línea] Boston, MA (USA): now.tufts.edu, 29 de enero de 2015 [ref. 24 de noviembre de 2014] Disponible en Internet: http://now.tufts.edu/news-releases/wireless-electronic-implants-stop-staph-then-harmlessly-dissolve



New MRI technique allows detailed imaging of complex muscle structures and muscle damage

8 01 2015

TU/e and the Academic Medical Center in Amsterdam have together developed a technique that allows detailed 3D imaging of complex muscle structures of patients. It also allows muscle damage to be detected very precisely. This new technique opens the way to much better and more patient-friendly diagnosis of muscular diseases. It also allows accurate, non-invasive muscle examinations among top athletes. Martijn Froeling will receive a PhD for this research at TU/e today, Monday 29 October.

muscle structure pelvis | image: Martijn Froeling

Froeling uses diffusion tensor imaging (DTI), an MRI technique that allows the movements of water molecules in living tissue to be viewed. Because muscles are made of fibers, the movements of water molecules in the direction of the fibers are different from those in other directions. This characteristic allows muscles to be imaged with a high level of detail. This was already possible on a small scale with simple muscles, but thanks to Froeling’s work it can now also be done on a larger scale and with complex muscle structures. More importantly, this improved technique also reveals very small muscle damage, because of the different movements of the water molecules in damaged muscle fibers.

3D images

To reach these results, Froeling improved the data acquisition process – the way the MRI scanner images the muscle under examination. This has to be performed relatively quickly, because it is uncomfortable for patients to lie in an MRI scanner for a long time, but at the same time it has to provide sufficiently detailed data. He also improved the processing of the acquired data into reliable 3D images. Physicians can now easily view complex muscle structures from all angles on-screen. No new equipment was needed; the researchers used standard widely available clinical systems.

Marathon runners

As a practical study, Froeling imaged a range of subjects including the thighs of marathon runners at different times: one week before a marathon, two days after it, and again three weeks after. He was able to visualize the muscle damage following the marathon. This was still visible after three weeks, even though the runners themselves in many cases no longer reported any pain in their muscles. Another study was of the pelvic floor in women; a good example of a highly complex muscle structure. The technique has proved to be capable of imaging this structure with great accuracy, which makes it potentially very valuable for the diagnosis of conditions such as uterine prolapse.

Wide application area

AMC Amsterdam and TU/e now intend to use this technique in studies of post polio syndrome and spinal muscular atrophy. Froeling believes there are numerous potential applications: there are around 600 different types of muscle disease and damage, and the new technique will improve the ability to study these. However further studies will first be needed: although the technique allows muscle disease or injury to be imaged it does not reveal the precise cause, which may be tearing, fat infiltration or other abnormalities. Clarification is also still needed on what are the normal values for healthy men and women of different ages, to provide a reference framework for identifying abnormalities in different groups of patients. Another kind of application is in examinations of top athletes, to allow timely detection of muscle damage or better estimation of the recovery time needed after injuries.

Martijn Froeling will gain his PhD at Eindhoven University of Technology on Monday 29 October for his thesis entitled ‘DTI of Human Skeletal Muscle, From Simulation to Clinical Implementation’. His thesis supervisor is prof.dr. Klaas Nicolay, professor of Biomedical NMR at TU/e. Co-supervisors are dr.ir. Gustav Strijkers (TU/e) and dr.ir. Aart Nederveen (AMC).

 

Tue.nl [en línea] Eindhoven (NL): tue.nl, 08 de enero de 2015 [ref. 29 de octubre de 2012] Disponible en Internet: http://www.tue.nl/en/university/departments/biomedical-engineering/news/29-10-2012-new-mri-technique-allows-detailed-imaging-of-complex-muscle-structures-and-muscle-damage/



Un ‘microchip’ ayudará a los parapléjicos a ejercitarse

25 11 2010

Científicos del Consejo de Investigaciones Científicas en Ingeniería y Física de Reino Unido (EPSRC, en sus siglas en inglés), han desarrollado un ‘microchip’ que libera impulsos eléctricos y que, implantado en la médula espinal, puede ayudar a los pacientes parapléjicos a ejercitarse.

eprsc

Los intentos anteriores de este tipo de aparatos de estimulación muscular habían fracasado debido a que eran demasiado voluminosos, aunque en esta ocasión estos investigadores han conseguido desarrollar un dispositivo “más pequeño que una uña” conocido como ‘Active Book’.

De hecho, este nombre se lo han puesto porque se coloca entre los nervios espinales como si fueran las páginas de un libro, liberando impulsos eléctricos directamente a la médula espinal desde una serie de electrodos, a diferencia de los estimuladores convencionales que funcionaban desde el exterior aplicando impulsos en la piel.

Las unidades se adhieren a un ‘chip’ de silicio que queda herméticamente sellado para proteger a la unidad de la penetración de agua, ya que puede provocar corrosión. El objetivo es que los estudios piloto para probar el ‘Active Book’ comiencen el próximo año.

Además, y según explica el profesor Andreas Demosthenous, autor de la investigación, en declaraciones a la BBC recogidas por Europa Press, el dispositivo incluye diferentes intensidades en función del campo de rehabilitación muscular.

“La investigación tiene el potencial de estimular más grupos musculares de lo que es posible actualmente con la tecnología existente” afirma el profesor Demosthenous, que justifica este potencial a que “puede implantarse en el conducto raquídeo”.

De este modo, la estimulación de más grupos musculares permite al usuario “tener movimiento suficiente para realizar ejercicio controlado como ciclismo o remo”, añade.

Según este científico, el ‘microchip’ podría también utilizarse para una variedad de funciones reconstituyentes, como la estimulación de los músculos de la vejiga para ayudar a superar la incontinencia, o en la estimulación de los nervios para mejorar la capacidad del intestino y suprimir espasmos.

Anteriormente, este tipo de aparatos habían presentado limitaciones por la dificultad de empaquetar electrodos y estimuladores musculares en una pequeña unidad aunque, gracias a los avances en la tecnología de láser para procesamiento de materiales, se han podido cortar pequeñísimos electrodos de una lámina de platino.

Europapress.es [en línea] Madrid (España): europapress.es 24 de noviembre de 2010 [ref. de 25 de noviembre de 2010] Disponible en Internet:

http://www.europapress.es/sociedad/salud/…