Micromolded Scaffolds for Photoreceptor Transplant

Article: Micro-molded ‘ice cube tray’ scaffold is next step in returning sight to injured retinas
Source: University of Wisconsin-Madison, via NEI
Published: April 21, 2021

Photoreceptors in the ice cube tray-shaped scaffold

Scientists and engineers are working to design and fabricate scaffolds to improve photoreceptor transplantation in eyes with retinal diseases. While there are many advances to create photoreceptors from stem cells, the researchers remark that obstacles remain to precisely deliver those photoreceptors to diseased or damaged eyes in ways that would result in forming the appropriate connections so that they can "effectively reconstruct the retina." The research team had previously designed a micro-molded biodegradable polymer scaffolding "patch" with wine-glass-shaped pores to hold the photoreceptors in place. In the current iteration, they designed the shape of the scaffold pores to be more like "ice cube trays," increasing the capacity to hold three times as many cells as well as reducing the amount of biomaterial used. The latter benefit would facilitate faster degradation of the material in the eye. The researchers used poly(glycerol-sebacate), or PGS, a material that is strong, compatible with the retina, and degrades within two months. The process to fabricate scaffolds with microstructures was technically challenging, though the labs discovered that using isopropyl alcohol helped to demount and release the PGS material from the molds cleanly. Using these techniques, they created ice cube tray-shaped scaffolds capable of holding 300,000 photoreceptors in a patch roughly the area of the macula. They next plan to file a patent for the design as well as proceed to testing in large animals. While these designs are early, they provide information for later improvements. As one of the researchers concludes, “We didn’t start out with supercomputers on our wrists and we’re not going to start out by completely erasing blindness in our first attempt. But we’re very excited about taking a significant step in that direction.”

My rating of this study: ⭐⭐⭐

Lee IK, Ludwig AL, Phillips MJ, et al. "Ultrathin micromolded 3D scaffolds for high-density photoreceptor layer reconstruction." Science Advances.  7(17):eabf0344. 21 April 2021. https://doi.org/10.1126/sciadv.abf0344