Figure 2.

Printing fidelity assessment of functionalized bioinks

(A) Representative optical (bright-field) images acquired for fidelity measurements for each GelMA bioink group: 0 (control), 100, 200, and 500 μg/mL SPIONs, at 1.5X (top) and 4× (bottom) magnifications. Scale bars in top and bottom rows represent 2 mm and 1 mm, respectively.

(B) Definition of the four geometric ratios quantified from microscopy images in (A) to assess fidelity of a 2-layer printed GelMA structure. These parameters include the strand diameter $D_r$, strand uniformity $U_r$, strand angle ${\alpha }_r$, and inter-strand area $A_r$ ratios (Equations (Equation 5), (Equation 6), (Equation 7), (Equation 8)).

(C) Comparison of quantified geometric ratios, defined in (B), for the four GelMA bioink compositions used at time zero of this study (immediately post printing). An n = 5 per experimental group was used for quantitative assays. ∗∗∗∗ p value < 0.0001.