Extracellular matrix-templating fibrous hydrogels promote ovarian tissue remodeling and oocyte growth.

Synthetic matrices which mimic the extracellular composition of native tissue create a comprehensive model for studying development and disease. Here, we have engineered a composite material which retains cell-secreted ECM for the culture of ovarian follicles by embedding electrospun dextran fibers functionalized with basement membrane binder (BMB) peptide in PEG hydrogels. In the presence of ECM-sequestering fibers, encapsulated immature primordial follicles and ovarian stromal cells aggregated into large organoid-like structures with dense deposition of laminin, perlecan, and collagen I, leading to steroidogenesis and significantly greater rates of oocyte survival and growth. We determined that cell aggregation restored key cell-cell interactions critical for oocyte survival, whereas oocyte growth was dependent on cell-matrix interactions achieved in the presence of BMB. Here we have shown that sequestration and retention of cell-secreted ECM along synthetic fibers mimics fibrous ECM structure and restores the cell-cell and cell-matrix interactions critical for engineering an artificial ovary.