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3D Printing of Bone

Credit: belekekin/Adobe

Credit: belekekin/Adobe

By Naomi Paxton

Hospitals are establishing 3D printing facilities that will make patient-specific bone tissue substitutes widely available.

Over the past decade, 3D printing has been making waves in many industries, from 3D printing mechanical parts for rockets and aircraft to large-scale 3D printing of low-cost housing and on-demand 3D printing of food and form-fitting fashion. The ability to extrude, deposit, bind or melt materials layer-by-layer into 3D structures offers a range of benefits over traditional subtractive manufacturing methods and injects personalisation and customisation into automated manufacturing.

This is highly advantageous for medical applications. To date, approaches to healthcare treatment have been largely divided into either personalised solutions that are expensive and/or labour-intensive, or automated solutions where the mass manufacture of everything from medical devices and implants to surgical tools and prosthetics provides lower cost “off-the-shelf” or “one-size-fits-all” approaches. However, the advantages of both approaches can be combined by introducing 3D printing, more generally known as additive manufacturing, to automatically print one-off products to suit individual patients.

This revolution in manufacturing opens many doors in the development of strategies to solve major challenges in healthcare. For example, large bone defects remain a significant clinical challenge. Following traumatic accidents, congenital birth abnormalities or the excision of diseased tissue such as bone tumours, large bone voids can be very challenging for surgeons to treat. Grafting involves taking bone tissue from another area of the patient (typically the hip) or from a donor, and using this healthy donor bone to fill the bone void. However, donor material is scarce and patients have increased risk of infection and tissue rejection, and are left with two healing sites. Alternatively, plastic or metallic implants can be used to reinforce bone defects, but long-term complications with such implants can severely impact a patient’s quality of life, as well as having significant financial burden.

An emerging research field, known as biofabrication, aims to develop 3D printing-based solutions to clinical challenges such as these. In the case of treatments for bone loss, researchers both in Australia and around the world are making significant headway in biofabricating functional, patient-specific bone tissue substitutes using 3D printing.

So how do we 3D print a bone? Biofabrication strategies are being developed to translate patient scan data to create a 3D computer model of the patient’s anatomy. From this model, a 3D model of the missing tissue can be created and sent to a medical 3D printer. Using biomaterials – biocompatible, biodegradable and bioactive materials that can be processed into complex shapes with a 3D printer – as well as the patient’s own bone cells and other biological signalling molecules, personalised bone tissue scaffolds can be 3D printed to fit the patient’s exact bone defect and anatomy.

Bones play a vital role in the human body, providing mechanical rigidity, protection for vital organs and enabling our ability to move. Therefore, biofabricated bone tissue substitutes must provide adequate mechanical support to the defective tissue area, as well as serve their biological role to facilitate nutrient transfer and a blood supply. The development of suitable biomaterials and the design of these patient-specific scaffold implants are crucial to ensuring mechanical stability and biological functionality.

Using 3D printing, complex scaffold architecture can direct tissue growth throughout the implants and facilitate rapid tissue regeneration. In parallel, the biomaterials naturally degrade and dissolve into the body, resulting in complete tissue regeneration and bone healing.

As developments in 3D printing bone tissue rapidly draw closer to routine clinical use, we anticipate a sharp rise in the implementation of 3D printing in hospitals around the country such as the Herston Biofabrication Institute at the Royal Brisbane & Women’s Hospital, the Advanced Biofabrication Centre at St Vincent’s Hospital in Melbourne, and the 3D printing facilities at the Royal Perth Hospital. This exciting revolution in the ability to fabricate functional human tissues for rapid transplantation on-demand will drastically improve the treatment of tissue loss, lower healthcare costs and improve the quality of care for millions of Australians.

Naomi Paxton is a PhD student at the Queensland University of Technology, studying in the Biofabrication & Tissue Morphology Group led by Professor Mia Woodruff and ARC Industrial Transformation Training Centre in Additive Biomanufacturing. She is the inaugural winner of the Ezio Rizzardo Polymer Scholarship, administered by the Australian Academy of Technology and Engineering.