1 M cacodylate buffer (Agar Scientific Ltd., Stansted, Essex, UK) overnight and then dehydrated through a series of ethanol solutions, 20%, 50%, 70%, 90% and 3 changes in absolute ethanol. The discs were then placed for 2 min in Hexamethyldisilazane (Agar Scientific Ld, UK), removed and allowed to dry. They were then attached to aluminium stubs with adhesive carbon tabs (both Agar Scientific Ltd, UK), sputter coated with gold/palladium (Polaron E5OO, Bio-Rad, Dolutegravir mouse Richmond, Surrey UK) and viewed in a JEOL JSM-5410LV SEM

microscope (JEOL UK Ltd, Welwyn, Herts, UK) operating at 10 kV and 10 mm working distance. SEM images would also reveal the roughness of the coating; which might influence the cell’s shape and ability to differentiate. After 48 h of growth on SCH 900776 in vitro the test samples the cells were lysed with Passive lysis buffer (Promega), the lysate was brought in a black 96-well and the Dual Luciferase Reporter™ assay was performed using a Labsystems Luminoskan Ascent Plate Luminometer [43]. The Gli-responsive firefly luciferase was measured manually and

immediately after adding the Luciferase Assay Reagent II. Subsequently, the Stop&Glo component was added to measure the constitutive Renilla expression. A relative Gli expression was obtained by dividing the firefly by the Renilla luminescence. As described in Paul and Sharma, 1999; the HA-beads were prepared by mixing 5 g hydroxyapatite (Sigma-Aldrich, Dorset, UK) with 10 ml of a 2% chitosan (Sigma) solution in 2% (v/v) acetic acid. The Fludarabine solution was poured in sunflower-oil and stirred to dispense the chitosan-HA-solution into small bubbles. The

bifunctional cross-linking reagent gluturaldehyde (Sigma) was added to cross-link the chitosan and the formed beads were filtered, washed with acetone and sintered at 1300 °C for 2 h. As the chitosan was burned away, pure porous HA-beads were left over [44]. The beads were soaked in 200 μM purmorphamine in PBS for 24 h and control beads were soaked in PBS only; while this Pur concentration is 100 × higher than the in vitro concentration tested it was expected that the amount would be sufficient to achieve a measurable effect. Fertilized eggs (J.K. Needle and Co., Herts, UK) were incubated at 39 °C within the first week upon arrival. A host egg was windowed at day 3 [45] to be able to use the chicken chorioallantoic membrane (CAM) as a culture substrate at day 7. The femurs were isolated from donor eggs at day 14. All soft tissues were removed from the femur and a small defect was made with a tip of a needle (BD Microlance 3). 10 beads were taken with a micropipette and injected onto the defect and pushed further into the defect with a needle-tip. This was performed using beads soaked in purmorphamine and control beads without purmorphamine (n = 3). The femur with the implant was brought on the CAM of the host egg, the window was sealed with plastic tape and the host egg was incubated for another 7 days.