Periodic Reporting for period 1 - Heartbeat (3D-assembly of interactive microgels to grow in vitro vascularized, structured, and beating human cardiac tissues in high-throughput)
Reporting period: 2022-10-01 to 2025-03-31
Generating 3D in vitro functional tissues and organs in the millimetre scale for drug screening remains an unmet dream of modern medicine. Irrespective of great efforts in the field of tissue engineering to construct matrices for 3D cell growth based on injectable/pipettable hydrogels or implantable/non-pipettable scaffolds, it is not yet possible to generate human and personalized tissues with native-like structures and mature blood vessels. The main reason for this limitation is that current materials do not recapitulate the complexity and dynamics of the native cell environment. To create human tissues, induced pluripotent stem cells can differentiate in any cell type but temporal control of stem cell expansion, differentiation, and organization inside the same material is not possible up to now. HEARTBEAT will break with traditional ways to make 3D biomaterial structures by assembling and crosslinking a variety of unique pre-programmed, rod-shaped, and interactive microgels instead of molecular building blocks. The main aim is to achieve macroporous, aligned, actuatable, and degradable constructs after simple pipetting with controlled material and structural properties, which is not possible with conventional hydrogels. I will use a high-throughput system to screen the innumerable combinations of design parameters to systematically study (stem)cell-material and cell-cell interactions with the aim to grow complex and functional tissue. In HEARTBEAT, I will focus on using the interactive bottom-up microgel assemblies to create millimetre-scale beating heart tissues with a commercial automated liquid pipetting handler, which is connected to an incubator and high-throughput confocal microscope via a robotic arm. The project will elucidate how material properties, architectures, and actuation affect human heart tissue formation and vascularization and how the construct has to adapt to the growing tissue over time to provide the right extracellular environment.
1. Temporal and Sequential Delivery of Multiple Growth Factors Affects Vascularization Inside 3D Hydrogels
--> Here, combinations of angiopoietin-1, angiopoietin-2, and PDGF-BB improve vascularization of a human umbilical vein endothelial cells-fibroblast coculture inside polyethylene glycol-based hydrogels the most, while the optimal concentrations and time points of growth factor addition are determined. Moreover, fibroblasts, pericytes, and mesenchymal stem cells (MSCs) are compared as supporting cells, of which MSCs best promote vascularization in coculture. Additionally, the resulting blood vessels align with magnetically oriented rod-shaped microgels when cultured inside the Anisogel. To mimic fibrosis, transforming growth factor-beta is added, resulting in significantly smaller vessels and more collagen secretion. This in vitro study reveals that a cascade of growth factors can improve vascular formation in 3D hydrogels, which is important to create viable tissue-engineered constructs for therapies and in vitro healthy and diseased tissue models.
2. Cell-interlinked macroporous annealed particle scaffolds for tissue engineering (Cellular Architects at Work: Cells Building their Own Microgel Houses)
--> In this work, a cell-induced interlinking method for MAP scaffold formation is established, which avoids the necessity of chemical crosslinkers and pre-engineered pores to achieve micro- or macropores in these 3D frameworks. This method enables cells to self-organize with microgels into dynamic tissue constructs, which can be further controlled by altering the microgel properties, the cell/microgel ratio, and well shape. To form a cell-induced interlinked scaffold, the cells are mixed with dextran-based microgels and function as a glue between the microgels, resulting in a more homogenous cell distribution throughout the scaffold with efficient cell–cell interactions.
--> Here, combinations of angiopoietin-1, angiopoietin-2, and PDGF-BB improve vascularization of a human umbilical vein endothelial cells-fibroblast coculture inside polyethylene glycol-based hydrogels the most, while the optimal concentrations and time points of growth factor addition are determined. Moreover, fibroblasts, pericytes, and mesenchymal stem cells (MSCs) are compared as supporting cells, of which MSCs best promote vascularization in coculture. Additionally, the resulting blood vessels align with magnetically oriented rod-shaped microgels when cultured inside the Anisogel. To mimic fibrosis, transforming growth factor-beta is added, resulting in significantly smaller vessels and more collagen secretion. This in vitro study reveals that a cascade of growth factors can improve vascular formation in 3D hydrogels, which is important to create viable tissue-engineered constructs for therapies and in vitro healthy and diseased tissue models.
2. Cell-interlinked macroporous annealed particle scaffolds for tissue engineering (Cellular Architects at Work: Cells Building their Own Microgel Houses)
--> In this work, a cell-induced interlinking method for MAP scaffold formation is established, which avoids the necessity of chemical crosslinkers and pre-engineered pores to achieve micro- or macropores in these 3D frameworks. This method enables cells to self-organize with microgels into dynamic tissue constructs, which can be further controlled by altering the microgel properties, the cell/microgel ratio, and well shape. To form a cell-induced interlinked scaffold, the cells are mixed with dextran-based microgels and function as a glue between the microgels, resulting in a more homogenous cell distribution throughout the scaffold with efficient cell–cell interactions.
1. Temporal and Sequential Delivery of Multiple Growth Factors Affects Vascularization Inside 3D Hydrogels
--> Normally focus was on one to two growth factors, but in this work, we researched the effect of the interplay between five different growth factors on vascularization.
2. Cell-interlinked macroporous annealed particle scaffolds for tissue engineering (Cellular Architects at Work: Cells Building their Own Microgel Houses)
--> A cell-induced interlinking method for MAP scaffold formation is established, which eliminates the need for chemical microgel interlinking or pre-engineered pores to generate micro- or macropores within these 3D structures. This allows cells to autonomously arrange themselves alongside microgels, forming dynamic tissue constructs that can be further manipulated by adjusting microgel characteristics, the ratio of cells to microgels, and the shape of the wells.
--> Normally focus was on one to two growth factors, but in this work, we researched the effect of the interplay between five different growth factors on vascularization.
2. Cell-interlinked macroporous annealed particle scaffolds for tissue engineering (Cellular Architects at Work: Cells Building their Own Microgel Houses)
--> A cell-induced interlinking method for MAP scaffold formation is established, which eliminates the need for chemical microgel interlinking or pre-engineered pores to generate micro- or macropores within these 3D structures. This allows cells to autonomously arrange themselves alongside microgels, forming dynamic tissue constructs that can be further manipulated by adjusting microgel characteristics, the ratio of cells to microgels, and the shape of the wells.