Implementing ovarian tissue engineering for the maturation of primordial follicles, the most abundant follicle population in the ovary, holds a great potential for women fertility preservation. In my talk, I will describe our studies towards reconstructing the ovary microenvironment to support the culture, growth and maturation of primordial follicles. A macroporous alginate scaffolds with affinity-bound bone morphogenetic protein-4 (BMP-4) supported the development of porcine primordial follicles up to the pre-antral stage within 21 days. When developed in vivo, after xeno-transplantation of the follicle devices supplemented with additional angiogenic factors, the follicles reached antral size and secreted hormones at levels leading to restoration of ovarian function in ovariectomized SCID mice. Our results provide first affirmation that the implementation of macroporous structure and affinity binding presentation of growth factors are critical for promoting follicle maturation in-vitro and in-vivo.