Fabrication of capillary-like structures with Pluronic F127® and Kerria lacca resin (shellac) in biocompatible tissue-engineered constructs

Abstract

The fabrication of large cellular tissue-engineered constructs is currently limited by an inability to manufacture internal vasculature that can be anastomosed to the host circulatory system. Creation of synthetic tissues with microvascular networks that adequately mimic the size and density of in vivo capillaries remains one of the foremost challenges within tissue engineering, as cells must reside within 200-300 μm of vasculature for long-term survival. In our previous work, we used a sacrificial microfibre technique whereby Pluronic® F127 fibres were embedded and then sacrificed within a collagen matrix, leaving behind a patent channel, which was subsequently seeded with endothelial and smooth muscle cells, forming a neointima and neomedia. We now have extended our technique and describe two approaches to synthesize a biocompatible tissue-engineered construct with macro-inlet and -outlet vessels, bridged by a dense network of cellularized microvessels, recapitulating the hierarchical organization of an arteriole, venule and capillary bed, respectively. Copyright © 2016 John Wiley & Sons, Ltd.

The Effects of Adipose-Derived Stem Cells Differentiated Into Endothelial Cells and Osteoblasts on Healing of Critical Size Calvarial Defects

“…At the time of this writing, there are several research groups, including ours, working toward achieving this goal. 25,26 An interesting finding of this study was the markedly better bone regeneration detected in the stem cell-treated groups histologically in comparison to micro-CT scans. The reason for this discrepancy might be the failure to detect immature bone tissue with micro-CT as well as the different quantification methods (ImageJ vs SkyScan Software).…”

Advanced Cell and Tissue Biomanufacturing

“…This may enable complex vascularized and innervated tissues in the future. For example, to manufacture tissue-like systems with vascular conduits in 3D, fabricated sacrificial polymer layers can enable conduits to be created. ,, These fabricated polymers can be created through approaches like extruding or micromachining, which can create nonplanar features at a micrometer scale. These techniques enable the fabrication of 3D structures that are derived from more conventional manufacturing processes that have been used in the steel industry for decades.…”

“…Vascularization with host tissue is seen as a critical step in assuring success. Ex vivo models of neo-vascularization have been developed and can be exploited in a systematic study of printed tissue/host vascularization. ,, …”

“…This can be accomplished by the active transporting of the nutrients through a network of branching conduits (the vasculature) that assures that no cell is farther than 200–300 μm from this supply mechanism. All the suggested approaches are based on sacrificial conduit networks, indicating that the solution to this problem is converging. ,,, A sacrificial network is a blueprint of branching vasculature fabricated from a material that serves as a temporary mold. The cellular structure is constructed around this structure and, subsequently, the mold is sacrificed and removed (e.g., by variation of the temperature).…”

“…Ex vivo models of neo-vascularization have been developed and can be exploited in a systematic study of printed tissue/host vascularization. 79,80,83 A barrier to building multicellular structures that are functional is the lack of understanding of the necessary cues that need to be provided by scaffold or matrix. Development of in vitro model systems that allow testing the effects of single and combinatorial effects of factors and/or signaling molecules on the function of tissue constructs is needed.…”