Table 1.

Comparison between collagen microsphere and pellet cultures.

	3D culture method		Pellet	Microspheres
				FBS	ITS
Phenotypic features	Production Throughput		Low	High	High
	Cell-matrix interactions		Low	High	High
	Cell-cell interactions		High	Low	Low
	Cell density		High	Low	Low
Chondrogenic phenotype	GAG staining		Low	High	High
	Sox9	staining	High (but only a few cells)	High (Most cells)	High (Most cells)
		gene expression	+++	++	+++ (3/4 patients increased)
	Col II	staining	++ (less extracellular deposition, 3rd week very low)	+++	+++ (high extracellular deposition)
OA phenotype	Runx2	staining	++ Low activation	+++ High activation	+++ High activation
		gene expression	+	++	+(but ¼ highly upregulated)
	Col X	staining	++	++ (more extracellular deposition)	++
	MMP13	gene expression	+	+++	++ (but 2/4 patients upregulated)