In vitro aneurysm models: a comprehensive review of 3D-printed, computational, and hydrogel platforms

The clinical translation of endovascular implants and new therapeutics for aortic aneurysms depend broadly on the reliability of the experimental testing models utilized. In vivo models present serious ethical and logistical limitations. Conversely, in vitro modelling is a high fidelity, human relevant approach, with carefully controlled environments and quicker clinical translation. Using the systematic literature search method, literature was screened for the various types of in vitro platforms used in aneurysm studies and classified into three main categories: (1) 3D-printed replicas, (2) computational fluid dynamics models, and (3) tissue mimicking hydrogel phantoms. A critical evaluation of material properties, fabrication techniques and experimental applications has shown that material compliance is crucial to reproduce physiological wall motion, and hydrogels provide outstanding properties for multi-modal imaging validation (Ultrasound, MRI and computed tomography) and for mimicking the structure of tissues. Moreover, the use of experimental flow visualization techniques also helps to overcome the challenges of disturbed hemodynamic patterns characterization. While several in vitro aneurysm models have achieved luminal endothelialization, the biomimetic incorporation of arterial smooth muscle cells together with endothelial cells in tissue-engineered aortic constructs is lacking in the literature and is an important future area of vascular research. To sum up, this review synthesizes these different in vitro modalities and their clinical translational potential, providing a clearer framework for future implant and therapeutic evaluation.