Heterogeneity of Scaffold Biomaterials in Tissue Engineering

Abstract

Tissue engineering (TE) offers a potential solution for the shortage of transplantable organs and the need for novel methods of tissue repair. Methods of TE have advanced significantly in recent years, but there are challenges to using engineered tissues and organs including but not limited to: biocompatibility, immunogenicity, biodegradation, and toxicity. Analysis of biomaterials used as scaffolds may, however, elucidate how TE can be enhanced. Ideally, biomaterials should closely mimic the characteristics of desired organ, their function and their in vivo environments. A review of biomaterials used in TE highlighted natural polymers, synthetic polymers, and decellularized organs as sources of scaffolding. Studies of discarded organs supported that decellularization offers a remedy to reducing waste of donor organs, but does not yet provide an effective solution to organ demand because it has shown varied success in vivo depending on organ complexity and physiological requirements. Review of polymer-based scaffolds revealed that a composite scaffold formed by copolymerization is more effective than single polymer scaffolds because it allows copolymers to offset disadvantages a single polymer may possess. Selection of biomaterials for use in TE is essential for transplant success. There is not, however, a singular biomaterial that is universally optimal.

Keywords: biomaterials; decellularized organs; extracellular matrix scaffold; natural polymer; synthetic polymer.

Figure A1

Regenerative medicine is a discipline with contours still being defined. By nature, it incorporates and leverages numerous fields of health sciences, as illustrated in the figure below which is extrapolated, with permission, from Orlando G et al. Gut, 2013 [148].

Figure A2

Immune properties of ECM scaffolds obtained from the human pancreas. (A) Representative plots and (B) quantitation of carboxyfluorescein succinimidyl ester (CFSE) dilution in CFSE-labeled human naïve CD4⁺ T cells stimulated with anti-CD3/anti-CD28-coated beads cultured with or without pulverized ECM; (C) Representative plots and (D) quantitation of Annexin-V and 7-AAD expression as a measure of apoptosis/necrosis in human naïve CD4⁺ T cells stimulated with anti-CD3/anti-CD28-coated beads cultured with or without ECM; (E) Representative plots and (F) quantitation of FoxP3 expression in CD4⁺CD25⁺ cells converted from human naïve CD4⁺ T cells stimulated with anti-CD3/anti-CD28-coated beads and IL2 cultured with or without ECM (with permission from Peloso et al. Ann Surg 2015, ahead of print) [145]. * denotes p < 0.05.