Researchers 3D print “living” plastics

Photo: University of Auckland

Researchers in New Zealand say they have developed a technique to 3D print “living” and “self-repairing” plastics.

The living resin is a 3D printable material which can change its properties after it has been produced, including growing in size and mass and repairing when damaged. Developed by researchers at the University of Auckland, it could be used in medical implants and the recycling of plastics.

Self-repairing plastic offers the potential to reduce plastic waste, the cost and time to recycle which often means breaking down plastic objects into raw material for reuse.

The team say the “world-first” 3D printing method uses a technique known as RAFT (reversible addition fragmentation chain transfer) polymerisation. The new technique advances 3D printing in two main ways with the big breakthrough being that the RAFT technique used produced objects that Dr Jin calls “dormant”.

Traditionally 3D printing produces inert objects that cannot change. RAFT objects can insert new compounds to alter their properties, enabling the printing of objects with the ability to transform after production. Additionally, traditional 3D printed objects are “cured” or set with ultraviolet light.

The team came up with the idea of applying the RAFT technique to 3D printing in 2018, dubbing the project “THING” named after the 1982 movie.

“If 3D printing, often called additive manufacturing, is the new frontier of the fourth industrial revolution, this new technique is at the forefront of that frontier.”, Dr Jin said.

Dr Ali Bagheri said this new technique pushes to use visible light, such as green and red, which requires less energy and is safer. This potentially opens new opportunities in biomedical applications where it is not safe to use harmful UV light.

Dr Jin and Dr Bagheri of the School of Chemical Sciences from the Faculty of Science supervised the research, which was conducted alongside Honours students Chris Bainbridge, Kyle Engel and third-year undergraduate Briony Daley.

Engel gives the example of 3D printing shoes with this technique, and programming them to grow with the wearer.

The University of Auckland team collaborated with researchers from the University of New South Wales and University of Melbourne, and acknowledge support from the Endeavour Fund administered by New Zealand’s Ministry of Business, Innovation and Employment.