Bioassembly of three‐dimensional embryonic stem cell‐scaffold complexes using compressed gases

Abstract

Tissues are composed of multiple cell types in a well-organized three-dimensional (3D) microenvironment. To faithfully mimic the tissue in vivo, tissue-engineered constructs should have well-defined 3D chemical and spatial control over cell behavior to recapitulate developmental processes in tissue- and organ-specific differentiation and morphogenesis. It is a challenge to build a 3D complex from two-dimensional (2D) patterned structures with the presence of cells. In this study, embryonic stem (ES) cells grown on polymeric scaffolds with well-defined microstructure were constructed into a multilayer cell-scaffold complex using low pressure carbon dioxide (CO(2)) and nitrogen (N(2)). The mouse ES cells in the assembled constructs were viable, retained the ES cell-specific gene expression of Oct-4, and maintained the formation of embryoid bodies (EBs). In particular, cell viability was increased from 80% to 90% when CO(2) was replaced with N(2). The compressed gas-assisted bioassembly of stem cell-polymer constructs opens up a new avenue for tissue engineering and cell therapy.

Computer-aided patterning of PCL microspheres to build modular scaffolds featuring improved strength and neovascularized tissue integration

“…This consideration is in agreement with recent works on the plasticization of drug-loaded carriers by vapour mixtures of EtOH and dimethyl carbonate (de Alteriis et al 2015) as well as PLGA layer to build 3D scaffolds (Ryu et al 2007). Nevertheless, suitable alternative treatments for layers sintering can be that employing compressed fluids, namely CO 2 and N 2 that were not so far used to sinter PLGA layers having the dimensions of 10 mm side and 60 µm thick with or without seeded cells (Yang et al 2005, Xie et al 2009. As shown in table 1, the porosity and pore size features of the PCL scaffolds can be modulated from 38.4 ± 1.1% up to 67.6 ± 1.4% and from 76.9 ± 1.8 µm up to 1373.5 ± 14.9 µm, respectively, without affecting the interconnectivity of the pores.…”

Biomaterials for stem cell engineering and biomanufacturing

“…For instance, Xie et al . [176] employed a pressurized-CO 2 assisted technique to assemble PLGA microscaffolds containing ESCs layer by layer for tissue engineering. The cells in microcarriers were not restricted to ESCs.…”

Modular Strategies to Build Cell-Free and Cell-Laden Scaffolds towards Bioengineered Tissues and Organs

“…The final porous scaffolds were obtained by stacking layers with the help of an alignment mold followed by compressed CO2 bonding for 1 h. This solvent-free approach was successfully applied to cell-seeded PLGA layers, demonstrating that CO2 bonding ensured proper human MSCs viability and functions [101]. Later, Xie and co-workers also demonstrated the possibility of bonding PLGA layers using N 2 , which resulted in enhanced embryonic stem (ES) cells’ viability with respect to CO 2 [102].…”