PMV Shetty(1), S Fuchs(2), R Scherlieβ(3), F Waltz(3), H Qiu(4), L Siebert(4), D Frank(5), A Remes(1), OJ Müller(1*)

1: Department of Internal Medicine V, University of Kiel, and German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany; 2: Experimental Trauma Surgery, Department of Orthopedics and Trauma Surgery, University Medical Center, Kiel, Germany; 3: Department of Pharmaceutics and Biopharmaceutics, Kiel University, 24118 Kiel, Germany; 4: Functional Nanomaterials, Department for Material Science, Kiel University, Kiel, Germany; 5: Department of Internal Medicine III, University of Kiel, and German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany.

Introduction: Aortic aneurysms pose serious risks, including dissection, requiring timely intervention. While AAVs enable targeted gene delivery, off-target effects remain a concern. Hydrogels offer a promising strategy to enhance delivery precision.

Aim: Our goal is to develop a marine-derived alginate biogel platform for controlled AAV delivery to key aortic cell types—fibroblasts, smooth muscle cells, and endothelial cells—enabling localized, sustained release and enhanced therapeutic precision.

Methods: Two sterilization methods were compared: autoclaving alginate powder either before or after solubilization at 110 or 121 °C. Unlike direct cross-linking, alginate solutions were cast into molds, air-dried overnight, and then cross-linked with 10% CaCl₂ for 10 minutes. Biocompatibility was assessed via LDH release from rFibs after gel exposure. Expression of pro-inflammatory genes (IL-6, STAT1, TNF-α) was measured, along with EYFP gene expression in rFibs to evaluate AAV release from the gels.

Results: Both sterilization methods yielded similar results. Alginate gels were non-cytotoxic after 96 hours and but showed reduced IL-6 mRNA levels, suggesting anti-inflammatory effects. EYFP expression in rFibs confirmed effective AAV release and transduction.

Conclusion: In summary, our findings demonstrate that alginate gels are non-cytotoxic and do not elicit an inflammatory response in vitro. The presence of EGFP mRNA in fibroblasts further confirms successful viral release from the gels.

Outlook: Dialysis-based release testing will verify rate of AAV release from the films. Additionally, we will employ the described biomaterials for the delivery of therapeutic AAVs into thoracic aortic tissue in murine models.