New biomaterial strategies for ocular repair and regeneration – hydrogels, 3D printing, novel tissue-engineering approaches and breakthrough technologies

In ophthalmology, biomaterials and 3D printing have many applications, including fabricating preoperative eye models, personalized lenses and glasses, orbital implants, and drug delivery systems.This review, however, focuses on new biomaterial strategies for ocular tissue regeneration, taking into account the latest developments in hydrogels, 3D-printing, bioprinting and novel tissue-engineering approaches.Studies on the eye mainly focus on the cornea and retina, with only a few on the sclera and crystalline lenses.Regarding the cornea, 3D printing offers promising advances in creating a complete artificial cornea, and significant progress has been made in developing its three different layers.However, printing its multilayers remains challenging.Concerning the retina, most studies remain in the in vitro stage due to its high complexity and the many cell types that compose it.Ophthalmic biomaterials and bioinks must support cell viability and, in the case of the cornea, preserve transparency and provide high mechanical strength.Both cell-laden and acellular bioinks are being developed.Cell-laden bioinks enable direct tissue regeneration but pose challenges related to cell survival.Consequently, many studies have focused on acellular biomaterials, which offer an extended shelf life, enhanced sterility, and a more straightforward regulatory process.Nowadays, significant progress has been made in cell therapy, reprogramming, biomaterials, and 3D printing for ophthalmology.These advances may help millions of patients regain their vision and significantly improve their quality of life.Iris