Nutrient capsules maintain tear film homeostasis for human corneal lenticule transplantation

Corneal lenticule transplantation can be applied in the correction of refractive errors and various corneal dis-eases. However, current techniques to preserve cornea are limited due to their short preservation time and the structures and optical retention of cornea tissues. Inspired by the composition of the natural human tear film, a nutrient hydrogel capsule that could maintain the homeostasis of tear film was constructed for preserving human corneal lenticules in this study. The nutritional preservation solution containing sodium alginate was coordinated with calcium ions by rapid diffusion to form a stereoscopic capsule, in which chondroitin sulfate interacted with the corneal lenticule surface electrostatically to form a lubricating layer for three-dimensional preservation and nutritional supply. The light transmittance, cell activity, and collagen fiber density of human corneal lenticules after mid-term preservation in nutrient capsules were higher than those traditional preservation methods. Furthermore, after human allogeneic transplantation, the implanted lenticules remained transparent without displacement or graft rejection, and the corrected distance visual acuity increased by two or more lines in 70% of the patients' operated eyes after surgery. Nutrient capsules could provide not only a simple, safe, and controlled strategy for three-dimensional preservation, but also new approach for other living tissues preservation.