Effect of PEG MW, LG segment length, and L/G ratio in PaLGb-Lc macromer on NG size distribution (a–c) and cumulative BSA release (d–f) in PBS with incubation time. (g) The release kinetics of BMP2 (blue circles) and VEGF (red circles) grafted to P8-I and P12-II NGs, respectively. Figure 2g also shows the release kinetics of BMP2 (blue squares) and VEGF (red squares) directly added to SPELA and GelMA gels, respectively, without NG grafting. The abbreviations P4, P8, and P12 in (a–f) represent NGs made from macromers with PEG MW=4, 8, and 12 kDa and average LG segment length of 8. The abbreviations P4-I, P4-II, and P4-III in (a–f) represent NGs with 4 kDa PEG MW with 75%, 60%, and 50% lactide in LG segments, respectively. Morphology of the dried NGs is shown in the inset SEM images in (a–c). Error bars correspond to means ± 1 SD for n=3.