MIE491 Capstone: Prototype of a Handheld Bioprinter for in-situ Burn Treatment Delivery

Dr. Ehsan Samiei from the Centre for Research and Applications in Fluidic Technologies (CRAFT) at the University of Toronto ("Client”) was interested in developing a new method of treating deep burn injuries. Typical treatments such as skin grafting and “Artificial Skin” are invasive, lengthy, and can cause patients pain. One non-invasive treatment that has been gaining popularity is skin spraying, a form of 3D bioprinting, but its deposition on the wound bed is inconsistent. Thus, the Client began researching alternative applications of 3D bioprinting, leading to development of a handheld skin deposition device ("prototype”).

The Capstone Design team ("Team”) was tasked with designing a new handheld bioprinter ("design”) with a focus on improving mechanical performance while adhering to new requirements from the Client. The prototype consisted of many components that contributed to undesirable heaviness, complexity, and non-portability, such as a guiding wheel, motors, and cooling tubes. The Client also required the new design to accommodate jammed microgel inks, which is a type of shear-thinning biomaterial that would need to be tested against a new pressure-based control system. After consultations with stakeholders, the Team concluded that opting for a “brush-like” design was superior to the prototype’s “gun-like” design as it would produce a lighter, simpler, and more portable device. Notably, the brush also offered multiple ways for the operator to hold the device, which is favorable when traversing complex contours like the neck or trunk regions of the human body. 

The final design consisted of a control box to house all electronic components, the bioprinter that enables biomaterial crosslinking, and the printhead that delivers biomaterials onto wound beds. Some important metrics evaluated from testing were flow rate deposition, consistency of the deposition on the wound bed, and ease of handling. This design was able to conformally deposit 5% alginate at a flow rate of about 143 μl /s using a pressure-based system. 

Co-Authors: Alexander Chu, Peter Vuong, Kaiwen Zhang