IIT Mandi Develops “Sea-Urchin”-Inspired Coating for 3D-Printed Bone Implants

Researchers from the Indian Institute of Technology Mandi (IIT Mandi) have created a bio-inspired surface coating on 3D printed bone implants capable of mechanically disrupting bacteria and accelerate integration of the implant with bones. This research has been published in the Chemical Engineering Journal, and it employs tiny hydroxyapatite structures resembling sea urchins on biodegradable plastic scaffolds to tackle two key problems with orthopedic implants – bacterial infections and poor bone integration.

Large bone defects resulting from traumatic injury, infections or removal of a tumor still pose great challenges. Although there are 3D-printed implants that use polylactic acid (PLA) which can be tailored to fit the individual’s bone defect, the hydrophobic nature of PLA does not allow it to easily bond with bones. Infections because of the adhesion of bacteria and formation of biofilms may also cause implant failure and subsequent surgery.

Inspired by Nature

The research team—led by Dr. Sumit Murab along with Ankita Negi, Aakash Verma, K.M. Mohammed Sufiyan and Vedante Mishra have developed dual-layer coating by using hydroxyapatite which is the major constituent of human body bone.

The preparation of this layer involves a two-stage process where the 3D printed PLA scaffold first undergoes activation of surface by treating it with an alkaline solution that provides the sites of minerals. In the second stage, the scaffold undergoes hydrothermal treatment at 90°C leading to the formation of hydroxyapatite needle clusters in the form of a sea urchin structure.

This creates a surface that utilizes bone-compatible mineralization together with micro-structures that can cause mechanical damage to bacteria, unlike the use of antibiotics or antibacterial chemicals.

Towards Safer Orthopedic Implants

When the benefits of customization through 3D printing and the hydroxyapatite-based biomimicry surface coating technique are considered together, it appears that this is a promising way to create implants that allow bone integration and decrease the likelihood of bacterial colonization.

This relatively easy low-temperature modification technique may also become one of the possible options for changing properties of degradable polymer constructs. According to the research team, it could also become applicable to orthopedic and dental implants, as well as other biomedical devices in which prevention of infection is crucial.

The research illustrates how nature-inspired surface design and new 3D-printing technologies may be used together in order to create advanced biomedical materials.