Dynamic 3D in vitro platform engineered via low-cytotoxic DLP 3D printing for enhanced ovarian follicle culture

To mimic the in vivo culture environment, an in vitro platform should not only provide structural support but also recreate the cellular microenvironment. However, for enhanced cell growth and function, it is essential to incorporate a three-dimensional architecture and dynamic stimulation that resemble the actual physiological conditions. Here, a dynamic threedimensional (3D) culture platform is developed using digital light processing (DLP) 3D printing with sub-millimeter-scale features. A custom-formulated resin with reduced photoinitiator and UV absorber was selected to minimize cytotoxicity and improve printing resolution. Grayscale modulation and structural reinforcement are employed to mitigate overcuring and undercuring in DLP-based fabrication, thereby enabling the fabrication of geometrically precise and mechanically stable microstructures. The platform incorporates a buoyant hollow structure, which facilitates fluid-induced gentle motion, providing dynamic stimulation that mimics in vivo mechanical cues. Mouse ovarian follicle growth is significantly enhanced by the dynamic 3D culture platform compared to static culture and platform-free conditions. This enhancement is attributed to both mechanical stimulation and lattice-based architecture, which supports nutrient diffusion and inter-follicular signaling. Overall, the proposed platform provides a robust strategy for physiologically relevant, long-term in vitro follicle culture, offering broad utility in reproductive tissue engineering, fertility preservation, and pharmacological screening.