Engineering biomimetic tarsal microtissue via structurally zoned hydrogel scaffold for integrated eyelid reconstruction.

The tarsus is critical for maintaining eyelid structural integrity, functional stability, and ocular surface health. Tarsal defects result in dual impairments of mechanical support and meibomian gland secretion, leading to severe complications such as corneal exposure and epithelial damage. However, current tarsal substitute materials fail to simultaneously meet the requirements of anatomical biomimicry, mechanical compatibility, and functional tissue integration, thereby constituting a significant bottleneck in clinical repair. To address this challenge, we developed a novel biomimetic tarsal microtissue strategy: based on the natural anatomical structure of the tarsus, a structurally zoned gelatin methacryloyl (GelMA) hydrogel scaffold was fabricated via digital light processing (DLP) 3D printing. Its mechanical properties were further enhanced by mechanical stimulation combined with salting-out, achieving a strength and flexibility comparable to those of native tarsal tissue. Subsequently, the scaffold was seeded with rosiglitazone (Rosi)-induced differentiated human meibomian gland epithelial cells (hMGECs) to construct the biomimetic tarsal microtissue. In vitro and in vivo experiments demonstrated that this microtissue exerted excellent substitution effects. When implanted in situ into rat eyelid defects, it effectively provided mechanical support and promoted tissue regeneration. This integrated strategy offers a promising approach to structural reconstruction and clinical functional amelioration of tarsal defects, with significant potential to improve ocular surface health and clinical outcomes for patients.