Figure 1:

Characterization of the silk-HAP material. (a) Microcomputed tomography of a 3D printed 10x10x10 mm cube, showing the general aspect of the cube (top right), regular filament distribution and interconnected pores. Scale bar: 1 mm. (b) 3D-printed anatomical structures: femur (left); vertebra (right, top); mandible (right, bottom). Scale bar: 1 cm. (c) Scanning electron micrograph (SEM) of a 3D-printed construct (left), showing control of filament deposition and macroporosity; of the surface of the filament, showing microporosity (center); of the hydroxyapatite (HAP) powder used for the silk-HAP bone cement, showing particle distribution (right). (d) 3D printed cylinders, showing microporosity and control of filament deposition. Scale bar: 1 mm. (e) Unsintered (left) and sintered (right) 10x10x10 mm cube, 3D printed using the 10% silk condition, showing the effect of sintering on aspect and size of the constructs. Scale bar: 5 mm. (f) FTIR spectra of the HAP powder, silk/HAP immediately after printing (freeze-dried), and of silk/HAP after drying. (g) Compressive strength (MPa) and Young’s modulus of silk/hydroxyapatite bone cements after drying the constructs. The effect of concentration, immersion in PBS, and post-printing processes like sintering (1100°C, 3 hours). (n=5).