Thiol-functionalized collagen patch channelizes TGFβ1- JNK trafficking and reverses corneal stroma opacity

Pro-regenerative patches are appealing for cornea injuries owing to their robustness, and ease of use in clinical settings. Collagen-based synthetic patches are building blocks for corneal repair, but their cross-linker toxicity, less optical clarity, and deformation instability remain unresolved. In response to these challenges, the study introduces disulfide crosslinked thiolated collagen patches (CSH). Human umbilical cord collagen (UC) comprises abundant lysine; thus, more primary amines are available for thiolation. UC was thiol functionalized, whereby the degree of amine substitution is 38 %, and a 40.4 % increase in disulfide bonds confirms disulfide-mediated crosslinking. CSH exhibits remarkable biomechanics (3.3 MPa), adhesion strength (107.25 kPa), optical clarity (87 %), and proteolytic resistance compared to native collagen. The patches support sustained levofloxacin release for three days. HET-CAM assay and hemocompatibility confirmed non-irritancy. Ex vivo adhesion, drug permeation, and epithelial integrity validated their compatibility in rabbit eyeballs. In vitro studies in human corneal stromal cells evidence that the thiols mimic endogenous peptides, favoring cell adhesion and proliferation. The patches alleviate the fibrotic episodes by reducing TGFβ1 and vimentin, which attenuates the JNK signaling, leading to elevated expression of corneal clarity restoring proteins, TGFβ3 and Keratocan. Thus, disulfide-bonded collagen patches would be an effective therapeutic modality for stromal injury-associated blindness.