Thunder fluorescence microscope

Microgel ink printability was tested by both qualitatively and quantitatively assessing the shape fidelity of a printed lattice, in particular the retention and shape of square, open windows formed by the lattice and unwanted material spreading. After printing, lattice structures were imaged using a Leica THUNDER fluorescence microscope with a tile scan function. The ink spreading (Sp) and window printability (Pr_w) were determined using Equations (1) and (2), respectively.
$$Sp=\frac{A_t-A_a}{A_t}\times 100\%$$
$$P{r}_w=\frac{L^2}{16A_a}$$
where A_t and A_a are the theoretical and actual areas of the printed window, respectively, and L is the perimeter of the window. For an ink with ideal shape fidelity, which forms perfectly square windows, Sp = 0 (i.e., A_t = A_a) and Pr_w = 1. Values plotted represent measurements from the 36 windows of a lattice for each GelMA and gelatin microgel ink.