A new 3D-printing process has allowed researchers to tailor-make artificial body parts and other medical devices with built-in functionality.

3D-printing process
Multimaterial 3D printing process (Image: Nottingham University)

The advance from Nottingham University is said to offer better shape and durability, while simultaneously cutting the risk of bacterial infection.

In a statement, study lead, Dr Yinfeng He, from the Centre for Additive Manufacturing, said: “Most mass-produced medical devices fail to completely meet the unique and complex needs of their users. Similarly, single-material 3D-printing methods have design limitations that cannot produce a bespoke device with multiple biological or mechanical functions.

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“But for the first time, using a computer-aided, multi-material 3D-print technique, we demonstrate it is possible to combine complex functions within one customised healthcare device to enhance patient wellbeing.”

The University hopes the design process can be applied to 3D-print any medical device that needs customisable shapes and functions, such as highly-bespoke one-piece prosthetic limbs or joints to replace a lost finger or leg. Similarly, the process could custom print polypills optimised to release into the body in a pre-designed therapeutic sequence.

For this study, the researchers applied a computer algorithm to design and manufacture - pixel by pixel - 3D-printed objects made up of two polymer materials of differing stiffness that also prevent the build-up of bacterial biofilm. By optimising the stiffness in this way, they achieved custom-shaped and -sized parts that offer the required flexibility and strength.

Current artificial finger joint replacements use silicone and metal parts that offer a standardised level of dexterity for the wearer, while still being rigid enough to implant into bone. As a demonstrator for the study, the team 3D-printed a finger joint offering these dual requirements in one device, while also being able to customise its size and strength to meet individual patient requirements.

A bacteria-repelling artificial finger joint with customised strength distribution made with the multi-material 3D print process (Image: Nottingham University)

With an added level of design control, the team is said to have performed their new style of 3D-printing with multi-materials that are bacteria-resistant and bio-functional, allowing them to be implanted and combat infection without the use of added antibiotic drugs.

The team also used a new high-resolution characterisation technique (3D orbitSIMS) to 3D-map the chemistry of the print structures and to test the bonding between them throughout the part.

The study was carried out by the Centre for Additive Manufacturing (CfAM) and funded by the Engineering and Physical Sciences Research Council. The complete findings are published in Advanced Science.

Prior to commercialising the 3D-printing process, the researchers will broaden its potential uses by testing it on more advanced materials with extra functionalities such as controlling immune responses and promoting stem cell attachment