Jayne Robinson, a UD biology professor and department chair, spent two years developing a unique method of applying an organic compound that can help break up the defenses of antibiotic-resistant bacteria, potentially making antibiotics up to 1,000 times more effective against bacterial infections.
“Now, with the patent, we have companies that are interested in licensing it,” Robinson said.
Karolyn Hansen, a UD assistant biology professor, developed a more effective and environmentally friendly alternative to ceramic coatings for metallic biomedical implants that is derived from oyster shells.
“I would like to think that this is eventually a commercial technology,” Hansen said. However, more work is needed to culture oyster cells on a reproducible basis before it can be brought to market, she said.
Targeting bacterial biofilms
In the U.S. each year, at least 2 million people become infected with bacteria that are resistant to antibiotics and about 23,000 people die annually as a direct result of these infections, according to the Centers for Disease Control and Prevention. Many more people die from other conditions that were complicated by an antibiotic-resistant infection, officials said.
“One of the greatest threats to human health today is the rise of bacterial infections that are resistant to many and multiple antibiotics,” Robinson said.
Robinson developed a unique method of preparing and applying an organic compound known as a porphyrin to break up and prevent the formation of bacterial biofilms, more commonly known as slime.
Bacteria, which typically grow on surfaces as a community, create this biofilm as a defensive matrix that can be up to 1,000 times more resistant to antibiotics compared to an individual bacteria, she explained.
“Our idea was let’s target the slime — that is, the thing that is housing or encasing the bacteria,” Robinson said.
Porphyrin is known to kill bacteria when it is activated with light. However, most infections occur deep inside human tissue, which makes it difficult to reach them with the type of light needed to activate the compound.
“We took this compound that was not thought to have any activity in the dark and when we treated the bacteria that are in biofilms, it busted up the biofilms. Then you could actually kill those bacteria now with traditional antibiotics” or light activation, Robinson said.
Beyond fighting infection in human tissue, the process also could be used to sterilize surgical instruments and implants. In addition, Robinson is testing its ability to break up bacterial biofilms inside fuel storage tanks for the U.S. Air Force.
She shares the patent with Tracy Collins, now a post-doctoral fellow at Wright State University, who earned her doctorate under Robinson at UD.
Oyster-derived ceramic
Hansen, an oyster biologist, set out with her collaborators in 2005 to develop corrosion-resistant ceramic coatings technology for metals under a three-year grant from the Air Force Office of Scientific Research.
The traditional manufacturing process for ceramic coatings requires high temperature and pressure, as well as chemical solvents that are harmful to the environment.
In contrast, mollusks create their hard, outer shells under water in ambient pressure and temperature by secreting alternating layers of organic and mineral materials, similar to brick-and-mortar construction.
“Nature does it best,” Hansen said.
By depositing cells extracted from the oyster’s mantle — the specialized tissue responsible for shell creation — onto a surface, Hansen and her team were able to successfully induce the creation of oyster shell layers as a natural ceramic coating.
The process of extracting and depositing oyster cells to induce shell layering on a surface allows for “targeted delivery” of the ceramic coating at room temperature and pressure, with no chemical solvents, she said.
Beyond strengthening surgical implants and improving tissue adhesion, the technology could provide an alternative material for bone growth, provided it can be tolerated by the human body, Hansen said.
“It is long-term for any coatings technology and it’s long term for any biomedical applications, but you’ve got to start somewhere,” she said.
Hansen shares the patent with her husband, Douglas Hansen of the UD Research Institute; and Andrew Mount, Neeraj Gohad and MaryBeth Johnstone of Clemson University.
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