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Mussel Protein Adhesives: A Sticky Solution to Regenerate Damaged Eyes

A new bioadhesive derived from mussel proteins has demonstrated remarkable capacity in attaching amniotic membranes on damaged eyes with the help of visible light, leading the way to suture-free amniotic membrane transplantation procedures.

Shielding the eye is a thin mucous membrane called the conjunctiva that covers the front half of the eyeball and is responsible for lubricating and protecting our eyes from microorganisms. However, because it is constantly exposed to the air, this thin layer is most susceptible to damage by bacteria, dust, or microorganisms. In some cases, contamination or damage to the conjunctiva can lead to diseases like pterygium and potentially cause visual deterioration.

To remedy such conditions, clinicians employ a technique known as amniotic membrane transplantation (AMT), a procedure that allows for the removal of impaired tissues and reconstruction of damaged conjunctiva. The amniotic membrane is the innermost layer of the placenta that serves to protect the embryo. Because it contains many factors that support epithelial regeneration, transplanting the amniotic membrane to damaged eyes supports the regrowth of the conjunctiva and reconstruction of damaged ocular surfaces. However, present AMT involves stitching the membrane with sutures and attaching it to the surface of the eyeball, consequently leaving a scar. The process itself is also time-consuming and requires incredible precision.

To refine present methods of AMT, a team of researchers from Pohang University of Science & Technology (POSTECH), has developed a novel biomaterial made of light-activated mussel adhesive proteins, known as FixLight, that can replace sutures when performing AMTs and speed up operation time by five times.

Using mussel proteins, the researchers formulated a light-curable bioadhesive with liquid-solid photo crosslinking characteristics. When not exposed to light, the material remains in a liquid state. However, upon exposure to visible light of a specific wavelength, the material can quickly change its state from a liquid into a hydrogel.

The team sought to confirm the effectiveness and applicability of their biomaterial in AMT, particularly on determining whether or not FixLight can be used to substitute sutures. As such, they simulated the process of conjunctival reconstruction in a rabbit model.

In their simulated AMT surgery, the researchers evenly coated their liquid adhesive onto the defect site and transplanted an amniotic membrane onto the ocular surface of a rabbit model with conjunctiva defects. After exposure to visible light, they observed stable tissue adherence and saw that the final results of the surgery were similar to suture-treated cases even on the wet surface of the eye. Furthermore, as epithelial regeneration progressed on the transplanted amniotic membrane, the adhesive completely biodegraded and regenerated into an integrated epithelial tissue.

The simulation of AMT using FixLight showed optimistic results in conjunctival regeneration, demonstrating the bioadhesive’s potential to become a safe and effective alternative to conventional surgical procedures of AMT.

“The amniotic membrane transplantation is an important operation in ocular surface reconstruction and this visible light-curable bioadhesive enabled facile and rapid operation,” said Professor Woo Chan Park of Dong-A University College of Medicine. “This technique shows promise to be applicable to other ophthalmological surgeries such as closing of incisions after cataract operation or other transplantations of the ocular surface, such as conjunctival autografting.” [APBN]

Source: Maeng et al. (2021). Sutureless Transplantation of Amniotic Membrane Using a Visible Light-Curable Protein Bioadhesive for Ocular Surface Reconstruction. Advanced Healthcare Materials, 2100100.