Bilayer scaffolds based on gellan gum (GG) and nanoparticulate bioactive-glass (BAG) were developed by an integrative
approach based on engineering principles and characterization in biomimetic bioreactors. The osteo-inductive GG-BAG
layer containing 2 % w/w GG and 2 % w/w BAG (composition: 70 n/n % SiO2, 30 n/n % CaO) was produced by gelation
followed by freeze-drying to obtain open porosity in axial and radial directions. The chondral layer was obtained by
dispensing a warm 2 % w/w GG solution at 60˚C over the frozen macroporous GG-BAG layer at -25˚C. The temperatures
were optimized by applying a one-dimensional unsteady-state heat transfer model so to obtain a thin integration zone, 0.5
– 1 mm thick. The scaffolds were evaluated regarding bioactivity in a biomimetic bioreactor with specially designed
chambers to provide supply of two media relevant for chondral and bone tissues. In the present experiment, simulated
body fluid (SBF) was supplied countercurrently continuously during 14 days of the experiment (1.1 ml min-1 flowrate), while
dynamic compression (5 % deformation, 0.68 Hz frequency, 337.5 µm s-1 loading rate, 1 h / day) was applied on the
chondral layer, from day 7 to day 14. SEM analyses have confirmed the retained integrity of the scaffolds, as well as
formation of hydroxyapatite (HAp) uniformly throughout the osteo-layer of the scaffolds.Significantly higher bioactivity
under biomimetic conditions compared to static controls resulted in slightly but significantly increased compression
modulus. These results indicated a high potential of the applied integrative strategy for the development of biomimetic
bilayer scaffolds