UNSW Sydney
The tiny flexible 3D bioprinter developed at UNSW Sydney was able to 3D print a variety of materials with different shapes on the surface of a pig’s kidney.
Engineers from The University of New South Wales (UNSW Sydney) have developed a miniature and flexible soft robotic arm which could be used to 3D print biomaterial directly onto organs inside a person’s body.
3D bioprinting is a process where biomedical parts are fabricated from bioink to construct natural tissue-like structures.
The research from the UNSW Medical Robotics Lab, led by Dr Thanh Nho Do and his PhD student, Mai Thanh Thai, was done in collaboration with fellow UNSW researchers Scientia Professor Nigel Lovell, Dr Hoang-Phuong Phan, and Associate Professor Jelena Rnjak-Kovacina.
This work resulted in the creation of a miniature flexible 3D bioprinter that can be inserted into the body like an endoscope and directly deliver multi-layered 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, which is attached to the end of a long and flexible snake-like robotic arm, all of which is controlled externally according to the team. The researchers say that further development could allow medical professionals to access areas of the body that are hard to reach, via small skin incisions or natural orifices.
The team tested the device inside an artificial colon, as well as trying out different materials and 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,” said Dr Do, a Scientia Senior Lecturer at UNSW’s Graduate School of Biomedical Engineering (GSBmE) and Tyree Foundation Institute of Health Engineering (IHealthE).
Dr Do added: “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.”
The team says the approach also addresses limitations in existing 3D bioprinters. These limitations include surface mismatches between 3D printed biomaterials and target tissues/organs, as well as structural damage during manual handling, transferring, and transportation process according to the team.
Scientia Professor Nigel Lovell said: “Currently, there are no commercially available devices that can perform in situ 3D bioprinting on internal tissues/organs distanced from the skin surface. Some other proof-of-concept devices have been presented, but they are much more rigid and tricky to use in complex and confined spaces inside the body.”
The UNSW team says the smallest F3DB prototype produced has a similar diameter to commercially available therapeutic endoscopes, approximately 11-13 mm. This size is small enough to be inserted into a human gastrointestinal tract. The team says that the device could ‘easily’ be scaled smaller for future uses.
The device features a three-axis printing head mounted on the tip of a soft robotic arm. The printing head contains soft artificial muscles that allow it to move in three directions and works similarly to conventional desktop 3D printers says the team.
The printing nozzle can be programmed to print pre-determined shapes or can be operated manually if more complex or undetermined bioprinting is required. The soft robotic arm can bend and twist due to hydraulics and can be fabricated at required lengths.
The UNSW team also tested the cell viability of living biomaterial after being printed with the system. The researchers say that the experiments showed the cells were not affected by the process, with the majority observed to be alive after the printing. The cells continued to grow for the following seven days, with four times as many cells observed one week after printing according to the team.
F3DB, according to the researchers, could be useful for surgeries to remove certain cancers, such as colorectal cancer, with a process known as endoscopic submucosal dissection. The nozzle of the F3DB could also potentially be used as a type of electric scalpel to first mark then cut away cancerous lesions.
Water can also be directed through the nozzle to clean blood and excess tissue from sites. The team says faster healing can be promoted by the immediate 3D printing of biomaterial directly while the robotic arm is still in place.
“Compared to the existing endoscopic surgical tools, the developed F3DB was designed as an all-in-one endoscopic tool that avoids the use of changeable tools which are normally associated with longer procedural time and infection risks,” said Mai Thanh Thai.
The team says they plan to implement additional features, such as an integrated camera and a real-time scanning system, which could reconstruct the 3D tomography of the moving tissue inside the body.
