Abstract
Purpose :
To explore whether a synthetic stromal scaffold comprised of a novel hydrogel biomaterial can transform the scrolling tendencies of DMEK tissue to make it behave more like DSAEK tissue intraoperatively in an ex-vivo human surgical laboratory model.
Methods :
In this study, four types of scaffolds consisting of carboxymethylcellulose (CMC) and polyethylene glycol (PEG) in two different compositions - with or without hyaluronic acid (HA) - and two different architectures - monolayer or bilayer with an extra HA top coat - were designed and synthesized. Biomechanical analyses were performed using a uniaxial tensile study to evaluate whether four candidate scaffolds had handling properties (tensile modulus) similar to corneal stroma (n=7 for each scaffold), and adhesion tests were conducted to evaluate their adhesive properties (n=4 for each scaffold). Experiments were conducted with human donor corneas to evaluate whether these two properties could be combined into a single biomaterial that was strong and flexible enough to be pulled through a 5 mm incision into a simulated model eye and sticky enough to adhere to DMEK tissue and thereby prevent it from scrolling once inside of a simulated anterior chamber (n=4).
Results :
Integration of HA into a carboxymethylcellulose-polyethylene glycol (CMC/PEG) monolayer significantly reduced the tensile modulus from 2.08 ± 0.32 MPa (CMC/PEG) to 0.60 ± 0.14 MPa (CMC/PEG/HA) (p < 0.0001), which is comparable to that of human corneal tissue; addition of an HA top layer did not contribute any mechanical strength. The addition of an HA top layer significantly increased the maximum adhesion force of both base scaffolds to the same level (~ 150 mN), regardless of the base composition (p < 0.0001). The CMC/PEG/HA-HA bilayer exhibited the most favorable biomechanical properties; simulated surgery with the prototype resulted in successful insertion of DMEK tissue in a flat configuration in 3 out of 4 simulated procedures.
Conclusions :
These preliminary studies justify development of this class of biomaterial to make DMEK surgery resemble the DSAEK procedure, thereby making it potentially easier for DSAEK surgeons to adopt DMEK without further skills acquisition.
This is a 2020 ARVO Annual Meeting abstract.