Bioprinting allows the fabrication of living constructs with custom-made 
architectures by spatially controlled deposition of multiple bioinks. This is 
important for the generation of tissue, such as osteochondral tissue, which 
displays a zonal composition in the cartilage domain supported by the underlying 
subchondral bone. Challenges in fabricating functional grafts of clinically 
relevant size include the incorporation of cues to guide specific cell 
differentiation and the generation of sufficient cells, which is hard to obtain 
with conventional cell culture techniques. A novel strategy to address these 
demands is to combine bioprinting with microcarrier technology. This technology 
allows for the extensive expansion of cells, while they form multi-cellular 
aggregates, and their phenotype can be controlled. In this work, living 
constructs were fabricated via bioprinting of cell-laden microcarriers. 
Mesenchymal stromal cell (MSC)-laden polylactic acid microcarriers, obtained via 
static culture or spinner flask expansion, were encapsulated in gelatin 
methacrylamide-gellan gum bioinks, and the printability of the composite 
material was studied. This bioprinting approach allowed for the fabrication of 
constructs with high cell concentration and viability. Microcarrier 
encapsulation improved the compressive modulus of the hydrogel constructs, 
facilitated cell adhesion, and supported osteogenic differentiation and bone 
matrix deposition by MSCs. Bilayered osteochondral models were fabricated using 
microcarrier-laden bioink for the bone compartment. These findings underscore 
the potential of this new microcarrier-based biofabrication approach for bone 
and osteochondral constructs.