Prof. Milica Radišić

Professor at the University of Toronto, Tier 1 Canada Research Chair in Organ-on-a-Chip Engineering and a Senior Scientist at the Toronto General Research Institute

Title: 3D Printing of Bioelastomers and Granular Materials for Engineering of Organotypic Structures

Abstract

The functional integrity of engineered tissues and organ-on-a-chip systems, including attributes like permeability and contractility, hinges on the characteristics of their scaffolds. Scaffolds designed for soft tissue engineering and organ-on-a-chip applications necessitate meticulous control over several parameters: a) microscale structural precision, b) elasticity ranging from 1kPa to 500 kPa, c) mechanical anisotropy, and d) biocompatibility. While complex structures can be 3D printed using hydrogels, their relatively low mechanical strength (1-10kPa) often leads to structural collapse under cellular traction forces during tissue formation. Conventional polymers like PLGA offer higher rigidity (1-200MPa) but are excessively stiff for soft tissues and inherently impede the permeability of proteins and cells.
These challenges are particularly pertinent in vascularization strategies that demand the embedding of branching conduits within a cell-supportive lattice, simultaneously managing mechanical properties, and in the engineering of complete functional organs such as the heart’s left ventricle. In my presentation, I will address the use of extrusion 3D printing with thermoplastic elastomer composites, a development that has enhanced the fabrication efficiency of the Biowire heart-on-a-chip device by more than 60,000%. Furthermore, I will explore a high-throughput 3D printing method employing coaxial extrusion. This technique facilitates the creation of perfusable elastomeric microtubes with unprecedentedly small inner diameters (350 to 550 μm) and thin walls (40-60 μm), enabling the production of various biomimetic shapes, including those resembling the cochlea and kidney glomerulus, and the efficient generation of perfusable structures suitable for endothelial cell seeding.
Additionally, leveraging capillary microfluidics followed by UV crosslinking, we have produced monodisperse elastomeric polymer particles. These particles have significantly bolstered the structural integrity of hydrogel-based scaffolds in 3D printing, leading to the development of a novel class of self-healing and 3D printable granular materials with enhanced permeability. These advancements represent a significant leap in the fields of soft tissue engineering and organ-on-a-chip technology.

Biography

Prof. Milica Radišić is a Professor at the University of Toronto, Tier 1 Canada Research Chair in Organ-on-a-Chip Engineering and a Senior Scientist at the Toronto General Research Institute. She is also Director of the NSERC CREATE Training Program in Organ-on-a-Chip Engineering & Entrepreneurship and a co-lead for the Center for Research and Applications in Fluidic Technologies. She is a Fellow of the Royal Society of Canada-Academy of Science, Canadian Academy of Engineering, the American Institute for Medical & Biological Engineering, Tissue Engineering & Regenerative Medicine Society as well as Biomedical Engineering Society. She was a recipient of the MIT Technology Review Top 35 Under 35, Queen Elizabeth II Diamond Jubilee Medal, NSERC E.W.R Steacie Fellowship, YWCA Woman of Distinction Award, Killam Fellowship, Acta Biomaterialia Silver Medal, and Humboldt Research Award to name a few. Her research focuses on organ-on-a-chip engineering and development of new biomaterials that promote healing and attenuate scarring. She developed new methods to mature iPSC derived cardiac tissues using electrical stimulation. She is an Executive Editor for ACS Biomaterials Science & Engineering, Senior Consulting Editor for the Journal of Molecular and Cellular Cardiology, a reviewing editor for eLife and a member of the editorial board of another 8 journals. She served on the Board of Directors for Ontario Society of Professional Engineers, Canadian Biomaterials Society and McMaster University Alumni Association. She organized Keystone, EMBO and ECI conferences and numerous sessions at TERMIS and BMES meetings. She served as a Scientific Officer for the Canadian Institutes of Health Research and member of review panels for CIHR, NIH and Israel Ministry of Education. She is the Chair of Investment Committee for Serbia Innovation Fund. She is a co-founder of two companies TARA Biosystems (acquired by Valo Health), that uses human engineered heart tissues in drug development and safety testing, and Quthero that advances regenerative hydrogels. Her work has been presented in over 260 publications, garnering over 20,000 citations with an h-index of 71. Her publications appeared in Cell, Nature Materials, Nature Methods, Nature Protocols, Nature Communications, PNAS etc.