Porous tissue strands: avascular building blocks for scalable tissue fabrication

Biofabrication. 2018 Nov 23;11(1):015009. doi: 10.1088/1758-5090/aaec22.

Abstract

The scalability of cell aggregates such as spheroids, strands, and rings has been restricted by diffusion of nutrient and oxygen into their core. In this study, we introduce a novel concept in generating tissue building blocks with micropores, which represents an alternative solution for vascularization. Sodium alginate porogens were mixed with human adipose-derived stem cells, and loaded into tubular alginate capsules, followed by de-crosslinking of the capsules. The resultant cellular structure exhibited a porous morphology and formed cell aggregates in the form of strands, called 'porous tissue strands (pTSs).' Three-dimensional reconstructions show that pTSs were able to maintain ∼25% porosity with a high pore interconnectivity (∼85%) for 3 weeks. Owing to the porous structure, pTSs showed up-regulated cell viability and proliferation rate as compared to solid counterparts throughout the culture period. pTSs also demonstrated self-assembly capability through tissue fusion yielding larger-scale patches. In this paper, chondrogenesis and osteogenesis of pTSs were also demonstrated, where the porous microstructure up-regulated both chondrogenic and osteogenic functionalities indicated by cartilage- and bone-specific immunostaining, quantitative biochemical assessment and gene expression. These findings indicated the functionality of pTSs, which possessed controllable porosity and self-assembly capability, and had great potential to be utilized as tissue building blocks in distinct applications such as cartilage and bone regeneration.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adipose Tissue / cytology*
  • Alginates / chemistry
  • Cell Differentiation
  • Cell Proliferation
  • Cell Survival
  • Humans
  • Porosity
  • Stem Cells / cytology*
  • Tissue Engineering / instrumentation*
  • Tissue Scaffolds / chemistry*

Substances

  • Alginates