Tissue engineering: strategies, stem cells and scaffolds

Abstract

Tissue engineering scaffolds are designed to influence the physical, chemical and biological environment surrounding a cell population. In this review we focus on our own work and introduce a range of strategies and materials used for tissue engineering, including the sources of cells suitable for tissue engineering: embryonic stem cells, bone marrow-derived mesenchymal stem cells and cord-derived mesenchymal stem cells. Furthermore, we emphasize the developments in custom scaffold design and manufacture, highlighting laser sintering, supercritical carbon dioxide processing, growth factor incorporation and zoning, plasma modification of scaffold surfaces, and novel multi-use temperature-sensitive injectable materials.

Fig. 1

Differentiation of mouse embryonic stem cells to the osteogenic lineage shown by (A) alizarin red-stained mineral accumulation compared with (B) control (field of view 1100 × 950 µm).

Fig. 2

Aggregation differentiation of embryonic stem cells is enhanced by using biotin–avidin linkers attached to the cell surface: (A) 500 000 cells mL⁻¹ untreated at 10 h and (B) treated with avidin–biotin. The treatment has been shown to increase the rate of osteogenic differentiation and make the procedure more reproducible (field of view 1100 × 800 µm).

Fig. 3

Phase diagram for the point at which CO₂ becomes supercritical and can be used to melt polymers at ambient temperatures to produce porous scaffolds.

Fig. 4

Supercritical CO₂ produced poly lactic acid foamed porous block (5 mm) viewed using (A) X-ray micro-computed tomography in section and (B) reconstructed.

Fig. 5

Different distributions of cells (white) shown using X-ray micro-computed tomography cross-sections of CO₂ foamed poly lactic acid scaffolds (black; 10 × 4.7 mm) with (A) cells located mainly on the surface on untreated scaffolds but (B) cells throughout the scaffold treated using plasma polymerized deposition of a cell adherent core (ppAm) and non-adherent surface (ppHex).