EFFECTS OF TOPOGRAPHICAL FEATURES ON MICROVASCULAR NETWORK FORMATION

Abstract

Current advancements in tissue engineering and biomaterials have inspired researchers to develop highly biomimetic tissues including vascular grafts, cardiac patches, skin substitutes, bone tissues etc. All of these tissues in their natural form contains highly organized microfluidic network composed of blood vessels, capillaries and lymphatics. Vascular network is one the crucial component in tissue architecture that maintains exchange of gases, nutrients and metabolic byproducts. Importantly, engineered tissues having thickness greater than 150-200 μm cannot rely upon diffusive nutrient transport after implantation. Therefore, one of the biggest obstacle in current scenario is to develop vascular networks in engineered tissues that can perfuse with host vasculature. Several approaches have been tested in past to develop microvacular network in vitro. These include external provision of angiogenic growth factors or appropriate extracellular matrix (ECM) proteins that stimulate endothelial cells (ECs) to form pro-angiogenic vascular networks. Interestingly, a completely fascinating avenue of topographical stimulation is still needs to be explored in order to determine its potential to stimulate angiogenesis. The objective of this study was to develop de novo microvascular network in vitro by Human mesenchymal stem cell (hMSC)- EC co-culture and investigate influence of micron scale topographical features on characteristics of this microvascular network. To achieve this goal, we tested mussel inspired polydopamine (PD) based coating to improve polydimethylsiloxane (PDMS) surface properties for optimum cell attachment and spreading. Our results indicated that micron scale topographical features have significant influence on properties of microvascular network including vessel alignment, intercapillary distance and vessel length