Current materials for implants and respective procedures sometimes cause biorejection and medical complications. Although some implant materials using surgical steel and titanium have had success, an understanding of how materials interact with human physiology in the long term is still limited.

A recent report from the UK Medicines and Healthcare Products Regulatory Agency found that 56,000 patients with metal-on-metal hip implants were at risk of developing complications. Concerns that metal shavings and metal ions in the blood might result in tissue necrosis have encouraged a review of all patients with the implants. Orthopedic implants in other parts of the body or dental implants can also present risk as the body rejects foreign materials. The problems are not limited to metals: Plastics and ceramics can also fail because of the foreign-body reaction.

Some researchers have found materials and procedures that may improve the safety and longevity of medical implants. For example, researchers from Colorado State University developed blood-repellent titanium by using fluorinated nanotubes. The superhemophobic material prevents biorejection by physically preventing blood cells from coming in contact with the implant and coagulating. The development may enable long-term use of implants.

Researchers from Purdue University have taken a different approach by allowing blood to come into contact with their orthopedic implants. Instead, they use materials that gradually biodegrade and absorb safely into the body.

Implications

The biocompatibility of implants will continue to be a significant challenge for the development and use of implants for augmenting human physiology. With biocompatible materials, implants that enhance physical ability or provide biological analytics via bioelectronics may become possible. Embedded sensors in implants could provide postoperation metrics to patients and doctors to support successful rehabilitation and recovery.

Implants using deformable and flexible materials such as Cartiva may reduce pain for patients while improving physical capabilities (by improving on joint structure). Use of durable superhemophobic coatings may be an affordable method to lengthen implant lifetimes and protect patients.

Impacts/Disruptions

Although medical devices generally take a long time to reach commercial application, progress may accelerate. Additive manufacturing may enable new materials for implants and may lower costs for manufacturers, hospitals, and patients. Additive-manufacturing companies such as Markforged and Desktop Metal that work with metals may be able to provide customized medical implants for patients using biocompatible materials. In addition, metal 3D printing may enable fast turnaround for customized implants.

More testing of and research about the long-term effects of implants and the general biocompatibility of various materials is necessary. Although new implants will take time to obtain approval for use in medical applications, strong interest exists in improving implant technology and in providing safe, long-lasting devices. The interest may help accelerate progress.