Engineers from UNSW Sydney have developed a miniature and flexible soft robotic arm that could 3D print bio-material onto organs inside a person’s body.

3D bioprinting is a process for making biomedical parts from ‘bio-ink’ to construct natural tissue-like structures. It normally requires the use of large 3D printing machines to produce cellular structures outside the living body.

But now, research at UNSW has resulted in a tiny flexible 3D bioprinter that has the ability to be inserted into the body just like an endoscope and directly deliver multilayered biomaterials onto the surface of internal organs and tissues.

The proof-of-concept device, known as F3DB, features a highly manoeuvrable swivel head that ‘prints’ the bioink, attached to the end of a long and flexible snake-like robotic arm, all of which can be controlled externally.

The device features a three-axis printing head directly mounted onto the tip of a soft robotic arm. This printing head, which consists of soft artificial muscles that allow it to move in three directions, works very similarly to conventional desktop 3D printers.

The soft robotic arm can bend and twist due to hydraulics and can be fabricated at any length required. Its stiffness can be finely tuned using different types of elastic tubes and fabrics.

The printing nozzle can be programmed to print pre-determined shapes, or operated manually where more complex or undetermined bioprinting is required. In addition, the team utilised a machine learning-based controller which can aid the printing process.

To further demonstrate the feasibility of the technology, the UNSW team tested the cell viability of living biomaterial after being printed via their system.

Experiments showed the cells were not affected by the process, with the majority of the cells observed to be alive post-printing. The cells then continued to grow for the next seven days, with four times as many cells observed one week after printing.

The research team say that with further development, and potentially within five to seven years, the technology could be used by medical professionals to access hard-to-reach areas inside the body via small skin incisions or natural orifices.

Dr Thanh Nho Do, a Scientia Senior Lecturer at UNSW’s Graduate School of Biomedical Engineering (GSBmE) and Tyree Foundation Institute of Health Engineering (IHealthE), and his team have tested their device inside an artificial colon, as well as 3D printing a variety of materials with different shapes on the surface of a pig’s kidney.

“Existing 3D bioprinting techniques require biomaterials to be made outside the body and implanting that into a person would usually require large open-field open surgery which increases infection risks,” Dr Do says. 

“Our flexible 3D bioprinter means biomaterials can be directly delivered into the target tissue or organs with a minimally invasive approach.

“This system offers the potential for the precise reconstruction of three-dimensional wounds inside the body, such as gastric wall injuries or damage and disease inside the colon.

“Our prototype is able to 3D print multilayered biomaterials of different sizes and shape through confined and hard-to-reach areas, thanks to its flexible body.

“Our approach also addresses significant limitations in existing 3D bioprinters such as surface mismatches between 3D printed biomaterials and target tissues/organs as well as structural damage during manual handling, transferring, and transportation process."

The smallest F3DB prototype produced by the team at UNSW has a similar diameter to commercial therapeutic endoscopes (approximately 11-13mm), which is small enough to be inserted into a human gastrointestinal tract.

The researchers say it could easily be scaled even smaller for future medical uses.

More details are accessible here.