JUL 12, 2016 08:00 AM PDT

Face implants fight infection from gunshots

Researchers developing temporary implants for facial reconstruction are incorporating a unique way to deliver time-released antibiotics to protect against infection while a patient heals.

Wound infections from gunshot injuries to the face are common—and soldiers are at particular risk, as battlefield injuries are often prone to infection from multidrug-resistant species of bacteria that invade between the time of injury and treatment. Image Credit: U.S. Army Photo by Sgt. Marcus Fichtl, 2nd ABCT, PAO 4th Inf. Div./Flickr

Antonios Mikos, professor of bioengineering and chemical and biomolecular engineering at Rice University, develops materials to help repair severe craniofacial injuries from trauma or pathological defects like tumor removal. Specialized plastic space maintainers are designed to keep a pocket for new bone open while the overlying soft tissue heals. In later surgery, the implant is removed to make way for reconstruction of the bone.

In a new advance, porous polymethylmethacrylate (PMMA) implants are filled with a gel that leaches a protective antibiotic to surrounding tissue, which protects the tissue from infection for several weeks.

Researchers describe the implants in a paper published in Biomaterials Science.

“Infection is an important problem that needs to be considered with medical devices because bacteria can prevent the body from being able to heal,” Mikos says. “If the infection gets too severe, it can even cause tissues that were previously healthy to die.”

Infections from the external environment and from neighboring structures such as the nasal passages, the sinuses, and the mouth can attack vulnerable tissue, researchers say. Wound infections from gunshot injuries to the face are common—and soldiers are at particular risk, as battlefield injuries are often prone to infection from multidrug-resistant species of bacteria that invade between the time of injury and treatment.

Researchers have experimented with porous implants but found they are susceptible to invasion by infectious bacteria. The new solution fills the pores at the point of care with a thermogel that infuses the spacer as a liquid and turns into a gel when exposed to body heat.

The thermogel itself is special. It consists of a block copolymer, a self-assembling combination of two polymers that is also under investigation for the controlled release of chemotherapy drugs.

“Block copolymers can offer a lot of benefits since they are designed to take advantage of the strengths of individual polymers,” Mikos says. “The block copolymer we used for our study was designed to be able to take on water, become a gel at body temperature, and slowly degrade over the course of implantation.”

Porous implants have been tested in humans, but PMMA with thermogel has not. Researchers infused the gel with colistin, a last-resort antibiotic with strong side effects. The PMMA and copolymer combination enabled tight control of its release without disrupting its antibacterial activity. In testing, the implants initially released a burst of the antibiotic through diffusion. Over time, degradation of the copolymer would continue to release lesser amounts of the drug for up to 28 days.

The thermogel can be customized at the time of implantation with the appropriate antibiotics, which also affect the rate and duration of release, before infusion into the prefabricated spacer.

Source: Rice University

This article was originally published on futurity.org.
About the Author
  • Futurity features the latest discoveries by scientists at top research universities in the US, UK, Canada, Europe, Asia, and Australia. The nonprofit site, which launched in 2009, is supported solely by its university partners (listed below) in an effort to share research news directly with the public.
You May Also Like
APR 28, 2018
APR 28, 2018
Eating Dark Chocolate Reduces Stress, Improves Mood
We’ve heard that dark chocolate is good for us in reasonable amounts, but two unique studies from the Loma Linda University Adventist Health Sciences...
MAY 24, 2018
MAY 24, 2018
Isolating a Neurological Protein May Protect Against Inflammatory Disorders
Investigators from Osaka University have isolated a neurological protein involved in the activation of immune cells that normally protect against inflammat...
MAY 31, 2018
MAY 31, 2018
Immunosuppressant Drugs to Prevent Parkinson's Disease
Certain immune activity could be increasing a person’s risk of developing Parkinson’s disease (PD), but immunosuppressant drugs might solve the...
AUG 15, 2018
AUG 15, 2018
Therapeutic Macrophages Improve Rare Lung Disorder
The use of therapeutic macrophage transplantation in mice showed great improvement in rare lung disorder caused by deficient macrophages....
AUG 24, 2018
Cell & Molecular Biology
AUG 24, 2018
Chronic Allergies can Change Cells
Chronic rhinosinusitis is different from allergies; it leads to serious inflammation and swelling in the sinuses that can last for years....
AUG 28, 2018
Drug Discovery
AUG 28, 2018
Combination Therapy for Advanced Melonoma
According to a research study led by UCLA, a bacteria-like agent used in combination with an immunotherapeutic drug may help patients survive longer with a...
Loading Comments...