Engineering granular and metamaterial structures from biodegradable and biocompatible polyester elastomers

点击翻译按钮获取中文摘要

Granular and metamaterial structures have revolutionized the development of miniaturized devices and microactuation, yet their use in tissue and organ-on-a-chip engineering is limited. In the previous DG cycle, using 3D stamping of UV-crosslinkable elastomers my group created complex structures such as AngioChip, injectable tissues and beating heart ventricles. However, their assembly required multiple photolithography steps, and a tedious layer-by-layer process requiring considerable manual skill. I hypothesize that engineering of granular and metamaterial structures from a new generation of biocompatible elastomers will solve the issue of material versatility and scalable processing, while providing new capabilities, such as material property patterning and porosity control, that are not realized using current bulk elastomeric approaches. In Project 1, we will synthesize new biocompatible elastomers for a range of tissue engineering and organ-on-a-chip applications. Prepolymer rheology, crosslinking time and mechanical properties will be tested. Using microfluidics, we will create monodisperse ink particles from the new elastomers, and stabilize them using partial UV curing. We will explore controlled release of biomolecules from the ink particles, functionalize them with conductive domains and test triggered-healing properties. In Project 2, we will advance scaffold technologies through 3D printing of tubular and metamaterial structures using jammed elastomer particle inks. We expect to achieve a significantly higher permeability to proteins of the new tubular structures compared to those 3D printed from bulk elastomers. Gradients of properties within the tubes will be created by combining ink particles of various properties in distinct spatial locations. We will 3D print a permeable yet stable vascular lumen for perfusion and release of angiogenic factors and exosomes. While cell laiden hydrogels can be 3D printed with high resolution, their structure deforms as cells remodel the matrix. Polymers are more stable, but they are inherently non-permeable. We will solve this problem by co-printing cells and hydrogels together with elastomeric ink particles to improve structure stability and embed the cells into the vessel wall. Conical metamaterial  scaffolds will be created by 3D printing auxetic periodic lattice using new elastomer inks, to create a flexible structure that can uniquely support ventricle contraction. The described approach will enable us to increase throughput of structure production by 34,560 fold replacing a slow 3D stamping, requiring 72 hr for fabrication of one 1.5cm long tubular conduit, by a scalable 3D printing that requires only 7.2s. Project 1 and 2 are interconnected as polymers and elastomeric ink particles form Project 1, will be used to construct complex granular and metamaterial structures in Project 2. Three PhD, 2 MASc and 5 undergraduate students will be trained through the proposed studies.