2.4. Measurements of 3D Printing Accuracy—Alginate w/wo Particle Functionalization

The printing accuracy of the 3D alginate structure with and without particle characterization was investigated to detect any differences between pure alginate and alginate functionalized by nHA/SrHA particles. Briefly, a grid (10 × 10 mm) with a 5% infill density (0–90° pattern) was printed for each condition. To calculate printing accuracy, n = 3 grids were printed, and macroscopic images were acquired. For each printed grid, n = 3 measurements were performed on the inner fibers (n = 2) by ImageJ software (version 1.54d) and compared to the nozzle dimension (Ø = 410 µm) to obtain accuracy %, calculated by Equation (1):

The accuracy was considered acceptable for values ≥ 65% [34,35].