Oogenesis and folliculogenesis are considered as complex and species-specific cellular differentiation processes, which depend on the in vivo ovarian follicular environment and endocrine cues. Considerable efforts have been devoted to driving the differentiation of female primordial germ cells toward mature oocytes outside of the body. The recent experimental attempts have laid stress on offering a suitable microenvironment to assist the in vitro folliculogenesis and oogenesis. Despite developing a variety of bioengineering techniques and generating functional mature gametes through in vitro oogenesis in earlier studies, we still lack knowledge of appropriate microenvironment conditions for building biomimetic culture systems for female fertility preservation. Therefore, this review paper can provide a source for a large body of scientists developing cutting-edge in vitro culture systems for female germ cells or setting up the next generation of reproductive medicine as feasible options for female infertility treatment. The focal point of this review outlines advanced bioengineering technologies such as 3D biofabricated hydrogels/scaffolds and microfluidic systems utilized with female germlines for fertility preservation through in vitro folliculogenesis and oogenesis.
Schematic representation of species-specific differences in folliculogenesis between rodents and humans (A) plus estimates of the number of ovarian follicles in various species (B). The current and specific future applications of advanced technologies in female fertility preservation and in vitro folliculogenesis, utilizing 3D organ culture techniques, hydrogels, scaffolds, microfluidic systems, and bioprinters are illustrated and compared with the conventional culture systems (A and C). Some items created with BioRender.com
Utilizing cutting-edge bioengineered culture microenvironments, it is possible to achieve successful in vitro folliculogenesis and oogenesis for therapeutic purposes.