Researchers at the Indian Institute of Technology (IIT) Mandi have developed a bio-inspired surface coating for 3D-printed bone implants that could help address two major challenges in orthopaedic implants: bacterial infections and poor integration with surrounding bone.
The research, published in the Chemical Engineering Journal, uses tiny hydroxyapatite structures resembling sea urchins on biodegradable plastic scaffolds.
The research team developed a dual-layer coating using hydroxyapatite, a mineral that is a major constituent of human bone.
The coating creates microscopic needle-like structures that resemble the surface of a sea urchin. These structures can mechanically damage bacteria that come into contact with the implant.
Unlike conventional approaches that rely on antibiotics or antibacterial chemicals, the technology uses the physical structure of the coating to disrupt bacteria.
3D-printed implants made from polylactic acid (PLA) can be customised to match individual bone defects. However, the hydrophobic nature of PLA makes it difficult for the material to bond effectively with bone.
Bacterial adhesion and biofilm formation can also cause implant infections and ultimately lead to implant failure and additional surgery.
The IIT Mandi researchers sought to address both challenges through the bio-inspired coating.
The coating process involves two main stages.
First, the 3D-printed PLA scaffold is treated with an alkaline solution to activate its surface and create sites where minerals can form.
In the second stage, the scaffold undergoes hydrothermal treatment at 90°C. This results in the formation of clusters of hydroxyapatite needles arranged in a sea-urchin-like structure.
The resulting surface combines bone-compatible mineralisation with microstructures designed to mechanically disrupt bacteria.
According to the researchers, combining the customisation offered by 3D printing with the hydroxyapatite-based surface treatment could provide a promising approach for developing implants that integrate with bone while reducing bacterial colonisation.
The relatively simple, low-temperature modification process could also potentially be used to alter the properties of other biodegradable polymer structures.
The researchers said the technology may have applications in orthopaedic implants, dental implants and other biomedical devices where preventing infection is important.
The research demonstrates how structures found in nature can inspire new approaches to biomedical material design.
By combining 3D printing, biodegradable polymers and hydroxyapatite biomimicry, the IIT Mandi team has developed a coating approach aimed at improving both biological compatibility and resistance to bacterial colonisation.
The findings could contribute to future research into safer and more effective customised implants, although further development and evaluation would be needed before any clinical application.
