Bioactive film ‘can help improve implant bonding with bone’

A new technique for coating polymer implants with a bioactive film could help to increase bonding between the implant and surrounding bone.

This is according to researchers from North Carolina State University, the University of Cambridge and the University of Texas at San Antonio, who believe the method could improve the success rate of implants used in spinal surgeries and other applications.

Such implants are made using polyether ether ketone (PEEK), which offers mechanical properties similar to bone but does not bond well with the natural tissue. The new technique solves this problem using hydroxyapatite (HA), a calcium phosphate that does bond strongly to bone.

PEEK implants were coated first with yttria-stabilized zirconia (YSZ), then a layer of HA heated using microwaves. The YSZ layer acts as a heat shield, preventing the PEEK from melting, while the heat gives the HA a crystalline structure that makes it more stable in the body.

Proof-of-concept studies yielded promising results, allowing the team to go on and successfully demonstrate the effectiveness of their new method in an animal model.

Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State, said: "This treatment will probably increase the cost of an implant marginally, but should help minimise the need for follow-up surgeries – which means HA-treated implants will more than pay for themselves over time."