Microfluidic Generation of 3D Micro-hydrogel constructs for Cell Encapsulation and Cell – Cell Interaction Studies

Divya Bahadur¹, Liyuan Zhang², Subramanian Ramakrishnan¹, David A. Weitz²

1 Department of Chemical and Biomedical Engineering, FAMU FSU College of Engineering, Tallahassee, FL
2 School of Engineering and Applied Sciences, Harvard University, Cambridge, MA

Stem cells hold immense potential in tissue engineering applications due to their ability to differentiate into multiple cell types based on their cellular niche. In order for them to successfully differentiate and proliferate ex-vivo, it is imperative to design a microenvironment which is able to reasonably mimic the mechanical and biochemical native cell environment. We conduct in vitro studies to better understand the effect of different hydrogel matrices and intercellular interactions on the differentiation and proliferation of Human Bone Marrow Mesenchymal Cells (HBMSCs). We use droplet microfluidics to encapsulate HBMSCs using photocurable gelatin methacrylate (GelMA) and alginate hydrogels to study the effect of the encapsulating microhydrogel matrix on the proliferation and differentiation of HBMSCs. Further, we describe a strategy to coculture HBMSCs with Endothelial Cells (ECs), in 3D compartmentalized hydrogel microparticles in order to study the paracrine signaling pathways that exist between these cells and their effect on the differentiation potential of the HBMSCs. This system offers confinement of different cell types, isolation of paracrine from juxtacrine signaling, high surface area for transport, biocompatibility, control over cell ratios and good experimental statistics. Initial results show this platform is suitable for the long term culture of these cell types and detection of interactions between them.