In Vitro Model Extracellular Matrix Maturation Under Variable Stress Conditions

Abstract

The study aims to enhance the design process of tissue-engineered implants by evaluating the effects of scaffold reinforcement and cultivation conditions on extracellular matrix (ECM) development. The research investigates the hypothesis that mechanical stress drives ECM production and alignment. Furthermore, we have explored the potential of an in silico growth model to complement in vitro findings for accelerated development processes. The study employed fiber-reinforced and nonreinforced scaffolds fabricated using warp-knitted textiles and fibrin gel. Myofibroblasts embedded in the scaffolds were cultivated under static and dynamic conditions. ECM development was evaluated through mechanical testing, hydroxyproline assays, and microscopy, while an in silico growth model was used to predict ECM behavior. Static cultivation resulted in significant ECM development in both reinforced and nonreinforced samples, with nonreinforced scaffolds showing higher collagen content and alignment along the load direction. In contrast, dynamic cultivation inhibited ECM formation, potentially due to cross-contraction and washout effects. Fiber-reinforced scaffolds exhibited higher elasticity and sustained stress across cycles without structural damage. The in silico model provided valuable insights but overestimated mechanical properties due to limited validation data. Reinforced scaffolds maintained geometry and elasticity, suggesting suitability for load-bearing applications. Nonreinforced scaffolds facilitated higher ECM production but were prone to structural damage. Dynamic cultivation requires optimization, such as prestatic cultivation, to support ECM development. The combined in vitro and in silico approach offers a promising framework for scaffold design, reducing the reliance on iterative experimental processes.

Impact Statement

The development process of tissue-engineered implants is iterative. A model-based approach has the potential to make the entire process quicker and more cost-effective. We developed a high-throughput method for evaluating extracellular matrix growth and formation in tissue-engineered samples under static and dynamic conditions. Additionally, we used an existing in silico growth model to compare in vitro and in silico results. Model-based scaffold testing offers a novel alternative to the lengthy iterative processes traditionally used to optimize scaffolds for specific tissue engineering applications.