Delivery: CART Nanoparticles Ferry CRISPR RNA Into Corneal Endothelium

Corneal endothelial dysfunction, including Fuchs' endothelial dystrophy, is the leading indication for corneal transplantation, yet no non-viral platform has reliably reached this layer. The corneal endothelium maintains corneal clarity but cannot regenerate efficiently, making targeted, transient delivery attractive. The researchers screened 13 CARTs formulated with luciferase mRNA and selected CART 8, whose cationic polymer complexes RNA at acidic pH, enters cells and then self-degrades to release its cargo.

For editing, they rapidly mixed CART 8 with Cas9 mRNA and a chemically modified single-guide RNA targeting the Col8a2 start codon, then injected the nanoparticles into the anterior chamber of healthy mice. Two doses one week apart produced edited alleles in 4.0–18.8% of posterior-cornea sequences, compared with 0.1% using a control guide. Reporter mice showed edited areas covering 1.3–4.9% of the cornea after one dose and 2.3–11.9% after two.

CART 8 also delivered linear and circular reporter RNAs. It transfected primary human donor corneal endothelial cells in vitro and, using EGFP mRNA rather than CRISPR-Cas, the corneal endothelium of one green monkey (Chlorocebus sabaeus) eye in vivo. Mouse treatments caused no significant loss of endothelial cells, but the primate showed mild anterior-chamber inflammation and iris transfection. The work did not test disease rescue, endothelial function, CRISPR-Cas off-target editing or repeated-dose toxicity in diseased eyes.

The study was led by Paul Wender and Howard Chang at Stanford University. It was published in Science Advances on 21 August 2026.