Pullulan-conditioned cartilage. Schematic shows the methodology for conditioning cartilage with the bioadhesive pullulan prior to MSC delivery. Cartilage biopsies were taken from the articular cartilage surfaces of the tibial plateau of the knee or hip femoral head. The explant surface was coated for 10 minutes in pullulan, an α-1-4; α-1-6-glucan polysaccharide consisting of maltotriose units (A). Culture expanded PKH26-labelled MSCs were applied to conditioned cartilage explants and incubated on a rocking plate for 20 minutes. Unbound MSCs in suspension were removed by washing in PBS, leaving MSCs bound to cartilage which were fixed and analysed histologically (B). MSC, mesenchymal stem cells.