Living Material Architecture as the Reciprocal Interactions Between Materials and Embedded Cells

The interface between biomaterials and synthetic biology leads to engineered living materials that have superior properties such as tunability, programmability, growth, self-healing, disturbance sensing, and adaptation to their surroundings, etc. This three-dimensional interaction between cells and hydrogels made from synthetic polymers or nature-derived biopolymers gives rise to a smart, complex, dynamic, and stimulus-responsive system which opens up a new frontier for tissue engineering, regenerative medicine, self-healing materials, and sustainable building materials. However, the engineering of living materials is still in its infancy as the control of the properties including mechanical properties such as elasticity, stiffness, plasticity; swelling behaviour, microscale architecture, biological signalling, response sensitivity, stability, and deformation etc, is not well understood. Additionally, advancements in the 3-D printing, manufacturing, and assembly of material architecture are required to engineer functional materials. Our focus is on the engineering of load-bearing structures by cell embedding during scaffold fabrication using 3-D bioprinting in a spatially organised manner. An attempt has been made to engineer living materials of distinctive chemical and physical living structures by developing algae-laden hydrogel motifs to gain mechanistic insights into their morphology, pattern formation, and stability. The encapsulation of microalgae <i>Chlamydomonas reinhardtii </i>in 3D hydrogel scaffolds with predesigned geometries was carried out to examine different parameters such as material composition and its effect on bioprinting structures, mechanical properties of hydrogel such as swelling and stability in culture, pattern geometry, cell survival during the plotting, cell viability and growth by measuring oxygen release and chlorophyll, spatial distribution of cells within the matrix, and build structure stability. Further, the relationship between printing parameters and plotting material composition will be tested. Overall, the purpose of this study is to identify the mechanism of failure in 3-D living materials by identifying the role of algae-hydrogel interactions during the growth, stability, and deformation of <i>Chlamydomonas reinhardtii </i>in a hydrogel medium. The results from this study will facilitate the transition from microscale to macroscale living architecture.