Figure 5. Follicle growth and development is dependent on proteolytic hydrogel degradation.

a, Follicles were encapsulated in 5% PEG-VS cross-linked with a peptide with two plasmin degradation sequences (YKNx), and cultured for 10 days. From day 6 to 10, the follicle expansion in the YKNS condition is significantly greater than the YKND and Y_DKN_DR conditions (*, P<0.001). Error bars are SEM. b–e Hydrogels with the YKNR sequence did not maintain the follicle within the hydrogel beyond four days. (b) Follicles cultured in 2D adhere to and migrate on the culture plate, disrupting their 3D shape. (c–e) Follicles after 10 days of culture encapsulated within hydrogels cross-linked with peptides containing (c) YKNS, (d) YKND, and (e) Y_DKN_DR sequences. (f) The YKNS condition had the greatest antral rate formation and volumetric expansion. Different superscripts indicate significant differences (P<0.01). g, Fertilizable eggs arrested at metaphase-II (MII) following IVM of cultured ooytes; egg (e) and polar body (white arrowheads). h, Confocal image of an egg showing a MII spindle from a perpendicular perspective (white arrow); actin (red), DNA (blue), and β-tubulin (green). All scale bars on light micrographs (b–g) are 100 μm and the scale bar on (h) is 25 μm.