Farewell Interview: Long Zhang
Jul 17 2019
Patients with microtia usually undergo extensive surgical procedures to reconstruct the auricular cartilage in order to have aesthetically normal looking ears. The fabrication of a full size human ear however, requires a careful selection of biomaterials that satisfies the mechanical and biological properties needed, as well as a designated hardware/software interface.
Using a bioprinting approach, a patient’s MRI/CT scan of the contralateral ear is first digitally processed into a printable file format and mirrored. The scaffold will then be fabricated by a combination of sacrificial materials, structural supportive biomaterials and cell laden hydrogels. Inks will be arranged in a way that allows maximum porosity for tissue maturation, while still being robust for handling and surgical procedures. Stem cells are then cultured and given time to differentiate into chondrocytes prior to implantation. In parallel, the goals are to also develop a customised printer capable of delivering the required materials based on their physical properties and with a customised interface for easy operation for surgeons.
This is a clinical collaborative project that involves clinicians and engineers. Working together with an ENT surgeon to ensure the product is practical and translatable into a clinical environment, the team at UOW comes from a diverse background with mechanical and robotic engineers handling the hardware/software development (3D Alek). Material scientist and chemical engineers on bioink development and biomedical engineers looking at in vitro/in vivo characterisation of scaffolds.
We have completed the initial phase of printer and ink development, where a clinically relevant sized ear can be printed by a mixture of different bioinks and biomaterials. Through changes in printing parameters and our unique hardware design, different regions of the ear that vary in stiffness and flexibility can be easily represented and achieved in one single print run.
Initial work into the use of mesenchymal stem cells have been completed showing successful differentiation of these cells inside our bioink. Further studies are now looking at relationship between chondrogenesis and scaffold design and co-cultures using primary chondrocytes.