Sponsored By

Slippery liquid-infused porous surface (SLIPS) technology applied to medical-grade teflon for implantable use could obviate the need for patients to take antibiotics and, thus, help combat the development of antibiotic-resistant microorganisms.

Norbert Sparrow

November 1, 2016

3 Min Read
E-PTFE coating prevents biofilm formation on implanted medical devices

Chalk up one more victory for biomimicry, an approach to technological innovation that finds inspiration in the workings of nature to sustainably solve the human condition. Joanna Aizenberg, professor of chemistry and chemical biology and materials science at the Harvard School of Engineering and Applied Sciences (Cambridge, MA), engineered industrial and medical surface coatings that repel unwanted substances by studying the carnivorous Nepenthes pitcher plant. It uses the porous surface of its leaves to immobilize a layer of liquid water, creating a slippery surface for capturing insects. Slippery liquid-infused porous surface (SLIPS) technology that she and her team developed has been used to prevent the formation of ice, crude oil and biological materials on materials. They are now developing SLIPS recipes for use on implanted medical devices. 

Biofilms can form on implanted devices, and doctors typically prescribe antibiotics to patients to prevent the risk of bacterial infection. The rampant use of these drugs over several decades has led to the alarming rise of antibiotic-resistant bacteria, what some have called a looming antibiotic apocalypse. SLIPS coatings could eliminate the use of antibiotics for certain medical procedures and minimize the development of antibiotic-resistant microorganisms, according to the researchers. A paper describing the technology is published in Biomaterials.

“We are developing SLIPS recipes for a variety of medical applications by working with different medical-grade materials, tuning the chemical and physical features of these solids and the infused lubricants to ensure the stability of the coating, and carefully pairing the non-fouling properties of the integrated SLIPS materials to specific disturbing factors, contaminating environments and performance requirements,” Aizenberg said in a press release published on the Harvard university website. “Here we have extended our repertoire of materials classes and applied the SLIPS concept very convincingly to medical-grade teflon, demonstrating its enormous potential in implanted devices prone to bacterial fouling and infection,” added Aizenberg, who is also a Wyss Institute Core Faculty member.

The SEM image on the left shows a commonly used teflon surface implanted into mice that were infected with S. aureus. The unmodified device surface attracted the infectious bacteria (green). Red blood cells (red), immune cells (blue) and extracellular matrix material (yellow) are also shown to deposit on the surface. The image on the right (colored purple) shows the same teflon surface treated with SLIPS within the infected mice. It shows no adhesion of cells or deposition of extracellular matrix material. (Image courtesy of Wyss Institute at Harvard University.)

Searching for the most advantageous medical-grade polytetrafluoroethylene (PTFE) and lubricant combination that would preserve the anti-bacterial activity of innate immune cells—the first-line of defense against invading bacteria—Aizenberg’s team settled on expanded PTFE (ePTFE). Used in prosthetic grafts for cardiovascular reconstruction and mesh for hernia repair, as well as implants in a wide variety of reconstructive surgery, ePTFE tested well with lubricants with proven acceptable safety profiles, noted the release.

Animal studies confirmed that the materials resisted infection by bacteria and were associated with considerably less infiltrating immune cells and inflammatory abscesses than non-coated ePTFE, said Elliot Chaikof, co-leader of the study, who is a Wyss Institute Associate Faculty member, Chairman of the Roberta and Stephen R. Weiner Department of Surgery and Surgeon-in-Chief at BIDMC.

Previous medical SLIPS applications include coatings that can repel bacteria and blood from small medical implants, tools and surgical instruments that are made of steel or, more recently, coatings that help keep the glass surfaces of endoscopy and bronchoscopy lenses free from highly contaminating body fluids and thus transparent during procedures.

About the Author(s)

Norbert Sparrow

Editor in chief of PlasticsToday since 2015, Norbert Sparrow has more than 30 years of editorial experience in business-to-business media. He studied journalism at the Centre Universitaire d'Etudes du Journalisme in Strasbourg, France, where he earned a master's degree.


Sign up for the PlasticsToday NewsFeed newsletter.

You May Also Like