Sustained intravitreal delivery of carnosic acid by RADA16 peptide hydrogel protects the retina in acute ocular hypertension.
RADA16 peptide hydrogel just scored a win for sustained delivery in eye research. Researchers loaded this self-assembling peptide with carnosic acid and injected it into rat eyes to protect retinal cells from acute ocular hypertension — a model for glaucoma. The result: better retinal health, less inflammation, and a promising tool for managing oxidative stress.
Sci Rep
by Hu H, Wang Y, Jia D et al.
“Sustained intravitreal delivery of carnosic acid by RADA16 peptide hydrogel protects the retina in acute ocular hypertension. Hu H(1), Wang Y(1), Jia D(1), Luo S(1), Deng YF(2), Wang R(1), Liu X(1), Guo X(1), Wu G(3), Sun J(4), Liang L(5). Author information: (1)The Second People's Hospital of China, Three Gorges University, the Second People's Hospital of Yichang, Yichang, 443000, Hubei Province, China. (2)Beijing Key Laboratory for Separation and Analysis in Biomedicine and Pharmaceuticals, School of Medical Technology, Beijing Institute of Technology, Beijing, 100081, China. (3)College of Life Sciences, Wuchang University of Technology, Wuhan, 430223, China. (4)Anqing First People's Hospital affiliated to Anhui Medical University, Anqing, 246000, Anhui Province, China. (5)The Second People's Hospital of China, Three Gorges University, the Second People's Hospital of Yichang, Yichang, 443000, Hubei Province, China. liangliang419519@163.com. This study investigates the use of RADA16 hydrogels for delivering carnosic acid (CA) in glaucoma treatment. Rheological tests at 0.5% (w/v), 1% (w/v), and 2% (w/v) concentrations showed significant elasticity, with Young's moduli of 30.18 Pa, 16.22 Pa, and 26.66 Pa, respectively. The 1% (w/v) concentration had the lowest stiffness, ideal for intravitreal injection. SEM revealed the hydrogel's porous microstructure. The RADA16-CA system provided sustained CA release over 72 h, peaking at 6 h. In vitro, high CA concentrations (≥ 256 μg/mL) were cytotoxic, but RADA16 and RADA16-CA enhanced cell proliferation. RADA16-CA demonstrated superior efficacy and biocompatibility. In an acute ocular hypertension model, RADA16-CA improved retinal health in rats by reducing retinal nerve fiber layer thickness, ROS-positive cells, and pro-inflammatory cytokines, while boosting cell survival and antioxidant activity.These findings highlight the potential of the RADA16-CA sustained-release system as an optimized approach for glaucoma treatment. © 2026. The Author(s). Conflict of interest statement: Declarations. Competing interests: The authors declare no competing interests. Ethics: This study was conducted in compliance with the ARRIVE guidelines for reporting animal research. All animal experiments were performed in accordance with the experimental protocols and standards sanctioned by the Animal Ethics Committee of China Three Gorges University, as well as the Animal Experiment Center of China Three Gorges University (Approval Number: 2025030I).”
Here’s what matters:
The team tested RADA16 hydrogels at different concentrations. The sweet spot was 1% (w/v) — soft enough for easy injection, but still elastic and structurally robust.
Scanning electron microscopy showed the hydrogel’s porous network, ideal for slow, steady drug release.
Carnosic acid release peaked at 6 hours and lasted up to 72 hours. That’s a major upgrade over single-shot injections.
High concentrations of carnosic acid alone were tough on cells. But encapsulating it in RADA16 actually boosted cell growth, keeping toxicity in check.
In live rats with induced eye pressure, the RADA16-CA combo meant thicker, healthier retinal layers, fewer ROS-positive cells (think: lower oxidative damage), and better antioxidant activity. Inflammation markers dropped, too.
Key takeaway: Peptide hydrogels like RADA16 are more than just delivery vehicles. They actively support cell health and open up new ways to use challenging compounds like carnosic acid.
Researchers looking to push ocular studies forward should keep an eye on this peptide delivery tech. For more on peptide-based innovation, check out the peptide research index. If you’re sourcing materials for your own lab, the vendor directory can help you get started.
Peptide hydrogels aren’t just hype — they’re shaping the future of sustained, targeted delivery in eye research.
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