'Bio pen' aims to rewrite orthopaedic implants surgery

04 December, 2013

A handheld "bio pen" developed in the labs of the University of Wollongong will allow surgeons to repair damaged and diseased bone material by delivering live cells and growth factors directly to the site of injury, accelerating the regeneration of functional bone and cartilage.

Researchers from the UOW-headquartered Australian Research Council Centre of Excellence for Electromaterials Science (ACES) have developed the prototype BioPen that will give surgeons greater control over where the materials are deposited while also reducing the time the patient is in surgery.

Delivery of stem cells and/or growth factors into the injury site is currently through injection using a biomaterial carrier.

The BioPen works similar to 3D printing methods by delivering cell material inside a biopolymer such as alginate, a seaweed extract, protected by a second, outer layer of gel material. The two layers of gel are combined in the pen head as it is extruded onto the bone surface and the surgeon "draws" with the ink to fill in the damaged bone section.

A low powered ultra-violet light source is fixed to the device, allowing for the inks to be cured during dispensing and built up layer by layer. Following curing, the shell material will maintain its form, and allow the surgeon to construct a 3D scaffold in the wound site.

The composition of the cell-loaded material also provides greater protection and retention of cells and can be surrounded by a polymer core to add structural strength to the surgical site. It can also be seeded with growth factors or other drugs to assist regrowth and recovery.

All components in the implantable material are non toxic and tuned to biodegrade as the cells begin to populate the injured bone area. The design of the device allows it to be easily transported and the surgeon can operate with ease and precision in theatre.

The BioPen prototype was designed and built using the 3D printing equipment in the labs at the University of Wollongong and was recently handed over to clinical partners at St Vincent's Hospital Melbourne, led by Professor Peter Choong, who will work on optimising the cell material for use in clinical trials.

Professor Choong is Director of Orthopaedics at St Vincent's Hospital Melbourne and the Sir Hugh Devine Professor of Surgery, University of Melbourne.

The BioPen will help build on recent work by ACES researchers where they were able to grow new knee cartilage from stem cells on 3D-printed scaffolds to treat cancers, osteoarthritis and traumatic injury.

"This type of treatment may be suitable for repairing acutely damaged bone and cartilage, for example from sporting or motor vehicle injuries," Professor Choong said.

"Professor (Gordon) Wallace's research team brings together the science of stem cells and polymer chemistry to help surgeons design and personalise solutions for reconstructing bone and joint defects in real time."

The BioPen will be transferred to St Vincent's for clinical projects to be carried out at the proposed Aikenhead Centre for Medical Discovery in Melbourne.

"The combination of materials science and next-generation fabrication technology is creating opportunities that can only be executed through effective collaborations such as this," Professor Gordon Wallace, ACES director, said.

"What's more, advances in 3D printing are enabling further hardware innovations in a rapid manner."