Because the method does not require harsh chemicals or extensive heating, it could also be used to incorporate proteins and nucleic acids, which Hammond says have been very difficult to deliver safely in the body for treatments. She says their coating could deliver these biological molecules both safely and specifically to where they’re needed, cutting down on the overall cost.
For orthopedic implants, one layer of the coating would release antibiotics starting right after the surgery, combined with anti-inflammatory drugs. Later, with infection defeated by this powerful, localized treatment, another layer of the coating would release a protein-like growth factor to stimulate the growth of bone in order to secure the implant in place. Many such layers and a wide variety of molecules can be incorporated into the coatings, which could also provide a transparent coating for replacement lenses used in cataract surgery.
For tissue engineering, the coatings could be used for “evolvable materials scaffolds onto which cells can grow and have growth factors introduced over time, or have specific genes introduced over time that program them to become what we want them to become,” Hammond says.
Hammond is already in contact with orthopedics researchers and surgeons who say her coatings could be helpful. Myron Spector, director of orthopedic research at the Brigham and Women’s Hospital, who works with Hammonds, says that, although infections affect only a few percent of the hundreds of thousands of patients who receive hip and knee replacements in the United States, preventing such infections is important. “It’s not a high percentage…but it’s devastating when it occurs, and can be life-threatening.”
Mitchel Harris, an orthopedic surgeon at Brigham and Women’s Hospital in Boston, says the technology seems promising, but also notes, “Unless it is inexpensive, it’s going to face an uphill battle [to introduce the coatings], because the reimbursement for implants is going down. If the implant continues to take up more and more of the reimbursement amount, then hospitalization won’t be covered. It makes it difficult.”*
Hammond says that if animal trials go well, it will still be three years before the coatings can be tried out in humans. Spector says the work is “very clever” and that in addition to improving current treatments, it could suggest new ones.
*Clarification: The cost of the coatings is yet to be determined. The process for making them is very cheap, Hammond says, and most of the cost will come from the drugs used. In some cases, the coatings would eliminate the need for a second surgery and long hospitalizations, she says, so saving money.