New implants can reduce infection and lead to better recovery from orthopedic surgery

Superior knee and hip replacements have become a step closer after Flinders University and Chinese researchers further tested and developed a new orthopedic implant coating that has the powerful ability to ward off infection, as well as stimulate bone growth.

This technology, which was patented after more promising results were detailed in the journal Advanced functional materials, consists of embedded nanoparticles of silver and gallium (Ag-Ga) that can be easily applied to the surfaces of medical devices. The article is titled “Nano-coated silver and gallium particles as a new, biocompatible solution for antibacterial coatings“.

“The antibacterial capabilities of silver-derived compounds have been extensively investigated. However, the cytotoxicity of silver ions currently poses a major obstacle to the use of silver ions in medical materials,” says corresponding author Dr. Vi Khanh Truong, from the Faculty of Biomedicine. Nanoengineering Laboratory (BNL) at Flinders University.

“Our new formula incorporating Ag-Ga nanoparticles ensures the sustained release of silver and gallium ions in a very controlled manner to eliminate these problems.”

Lead author Matthew Flinders, Professor Krasimir Vasiliev, Director of the Biomedical Nanoengineering Laboratory at Flinders University’s School of Medicine and Public Health, says this discovery provides an urgently needed solution to infections associated with medical devices.

“The new material can be easily applied and controlled by spraying on various medical devices to protect them from infection, and it also provides an anti-inflammatory effect and stimulates bone growth,” says Professor Vasiliev.

“Our recent testing suggests that this combination of antibacterial protective properties and tissue integrity could benefit many devices in the fields of orthopedics, trauma as well as dentistry.”

Infections after orthopedic implant surgery are a global health problem, with infection rates ranging from 2% to 10% in developed countries and up to 15% in developing regions.

In the United States aloneThere are more than 100,000 cases of infections associated with orthopedic devices. A 2017 Australian study showed a 1.7% infection rate after hip or knee replacement surgeries. About 6% of orthopedic implant infections lead to intensive care, with a mortality rate of 4.6%. The cost of treating such infections can exceed US$100,000 per case.

The latest test was supported by collaborators including Professor Yunpeng Zhao, a surgeon at Qilu Hospital, and colleagues at Shandong University in China.

Ag-Ga combined nanoparticles have demonstrated potent antimicrobial properties against a wide range of bacterial strains in animal models.

This discovery has the potential to apply to many implantable devices, catheters and other access devices, and even wound dressings where infection is also an issue, says Dr Truong, from the Flinders Biomedical Nanoengineering Laboratory.

“Commercialization opportunities could make this solution available to doctors and patients in the near future – at a time when rising antibiotic resistance is another problem in global healthcare.”

GaLM was used to facilitate galvanic deposition of silver (Ag) nanocrystals on the oxide layer. GaLM not only acts as a carrier of silver through the process of galvanic substitution but also provides a controlled release mechanism for silver.

The first author, master’s student in biotechnology, Tien Thanh Nguyen, also worked with fellow researchers at Flinders on the latest study in collaboration with clinical experts from Shandong University and Shandong Hospitals.