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.

‘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. Tufts University

An injection of a patient

Needles almost too small to be seen with the unaided eye could be the basis for new treatment options for two of the world’s leading eye diseases: glaucoma and corneal neovascularization.

The microneedles, ranging in length from 400 to 700 microns, could provide a new way to deliver drugs to specific areas within the eye relevant to these diseases. By targeting the drugs only to specific parts of the eye instead of the entire eye, researchers hope to increase effectiveness, limit side effects, and reduce the amount of drug needed.

For glaucoma, which affects about 2.2 million people in the United States and is the second leading cause of blindness worldwide, the goal is to develop time-release drugs that could replace daily administration of eye drops. A painless microneedle injection made once every three to six months – potentially during regular office visits – could improve treatment outcomes by providing consistent dosages, overcoming patient compliance issues.

In the second disease, corneal neovascularization, corneal injury results in the growth of unwanted blood vessels that impair vision. To treat it, the researchers developed solid microneedles for delivering a dry drug compound that stops the vessel growth.

‘The power of microneedles for treating eye conditions is the ability to target delivery of the drug within the eye,’ said Mark Prausnitz, a Regents’ professor in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology. ‘We are developing different microneedle-based systems that can put the drug precisely into the part of the eye where it’s needed. In many cases, we hope to couple that delivery with a controlled-release formulation that would allow one application to treat a condition for weeks or months.’ EurekAlert

Oxford University doctors and scientists are starting the first safety trial of an experimental preventative Ebola vaccine regimen being developed by the Janssen Pharmaceutical Companies of Johnson & Johnson (Janssen).

The Oxford Vaccine Group, part of the University of Oxford Department of Paediatrics, aims to have vaccinated all 72 healthy adult volunteers by the end of January.

The development of this prime-boost vaccine regimen has been accelerated in response to the current outbreak of Ebola virus disease in West Africa, which has claimed over 6,000 lives. An effective vaccine would be an important step in controlling the spread of disease.

Volunteers for the trial, aged 18

New research is challenging what many obstetricians and physician anaesthesiologists believe is the best way to position women during labour.  According to a study, the traditional practice of positioning women on their side, with hips tilted at 15 degrees, during labour does not effectively reduce compression of the inferior vena cava, a large vein located near the abdominal area that returns blood to the heart, as previously thought.  In fact, not until the degree of tilt reached 30 degrees did blood flow only partially increase in patients, the study found.