Hierarchically Structured Biomaterials for Bone-on-a-Chip Devices and Bone Tissue Engineering

Natural tissues and organs are typically structured in a hierarchical fashion, in which the Extra-Cellular Matrix (ECM) provides a microporosity to optimally support cell growth while larger scale structures (e.g. vasculature and boundary layers) are incorporated to support the function and structure of the tissue and organ. To mimic this multiscale structuring in synthetic biomaterials we combine additive manufacturing with self-assembly. In this structuring technique the internal porosity is governed by self-assembly and the macroscopic structure is constructed by additive manufacturing. Emulsion templating is used as self-assembly technique to produce materials with a high microscale porosity. These emulsions can subsequently be used as photocurable resins for stereolithography, producing user-defined macroscale structures with a tissue-like microporosity. The mechanical properties of these materials can be varied via the changing the monomer ratio within the resin. We produce these hierarchical structured material in 3D structured materials such as woodpile-style scaffolds, microspheres with controllable diameter and as 3D microenvironments that can be integrated in standard poly-dimethylsiloxane (PDMS) based microfluidics. These scaffolds we currently investigate as a platform for bone-on-a-chip based devices and bone tissue engineering.