Plant Recombinant Human Collagen Type I Hydrogels for Corneal Regeneration

Michel Haagdorens, Elle Edin, Per Fagerholm, Marc Groleau, Zvi Shtein, Artūras Ulčinas, Amit Yaari, Ayan Samanta, Vytautas Cepla, Aneta Liszka, Marie José Tassignon, Fiona Simpson, Oded Shoseyov, Ramūnas Valiokas, Isabel Pintelon, Monika Kozak Ljunggren*, May Griffith*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Purpose: To determine feasibility of plant-derived recombinant human collagen type I (RHCI) for use in corneal regenerative implants Methods: RHCI was crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to form hydrogels. Application of shear force to liquid crystalline RHCI aligned the collagen fibrils. Both aligned and random hydrogels were evaluated for mechanical and optical properties, as well as in vitro biocompatibility. Further evaluation was performed in vivo by subcutaneous implantation in rats and corneal implantation in Göttingen minipigs. Results: Spontaneous crosslinking of randomly aligned RHCI (rRHCI) formed robust, transparent hydrogels that were sufficient for implantation. Aligning the RHCI (aRHCI) resulted in thicker collagen fibrils forming an opaque hydrogel with insufficient transverse mechanical strength for surgical manipulation. rRHCI showed minimal inflammation when implanted subcutaneously in rats. The corneal implants in minipigs showed that rRHCI hydrogels promoted regeneration of corneal epithelium, stroma, and nerves; some myofibroblasts were seen in the regenerated neo-corneas. Conclusion: Plant-derived RHCI was used to fabricate a hydrogel that is transparent, mechanically stable, and biocompatible when grafted as corneal implants in minipigs. Plant-derived collagen is determined to be a safe alternative to allografts, animal collagens, or yeast-derived recombinant human collagen for tissue engineering applications. The main advantage is that unlike donor corneas or yeast-produced collagen, the RHCI supply is potentially unlimited due to the high yields of this production method. Lay Summary: A severe shortage of human-donor corneas for transplantation has led scientists to develop synthetic alternatives. Here, recombinant human collagen type I made of tobacco plants through genetic engineering was tested for use in making corneal implants. We made strong, transparent hydrogels that were tested by implanting subcutaneously in rats and in the corneas of minipigs. We showed that the plant collagen was biocompatible and was able to stably regenerate the corneas of minipigs comparable to yeast-produced recombinant collagen that we previously tested in clinical trials. The advantage of the plant collagen is that the supply is potentially limitless.

Original languageAmerican English
Pages (from-to)269-283
Number of pages15
JournalRegenerative Engineering and Translational Medicine
Issue number2
StatePublished - Jun 2022

Bibliographical note

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  • Cornea regeneration
  • Limbal stem cells
  • Plant collagen
  • Recombinant human collagen type 1
  • Tissue engineering


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