Synthetic alternatives to Matrigel

Abstract

Matrigel, a basement-membrane matrix extracted from Engelbreth-Holm-Swarm mouse sarcomas, has been used for more than four decades for a myriad of cell culture applications. However, Matrigel is limited in its applicability to cellular biology, therapeutic cell manufacturing and drug discovery owing to its complex, ill-defined and variable composition. Variations in the mechanical and biochemical properties within a single batch of Matrigel - and between batches - have led to uncertainty in cell culture experiments and a lack of reproducibility. Moreover, Matrigel is not conducive to physical or biochemical manipulation, making it difficult to fine-tune the matrix to promote intended cell behaviours and achieve specific biological outcomes. Recent advances in synthetic scaffolds have led to the development of xenogenic-free, chemically defined, highly tunable and reproducible alternatives. In this Review, we assess the applications of Matrigel in cell culture, regenerative medicine and organoid assembly, detailing the limitations of Matrigel and highlighting synthetic scaffold alternatives that have shown equivalent or superior results. Additionally, we discuss the hurdles that are limiting a full transition from Matrigel to synthetic scaffolds and provide a brief perspective on the future directions of synthetic scaffolds for cell culture applications.

Fig. 1∣. Comparison of Matrigel and synthetic scaffolds.

a ∣ The composition of Matrigel is unamenable to modifications, ill-defined, complex and highly variable, resulting in heterogeneities in both biological and mechanical properties. As it is animal-derived, Matrigel may also contain xenogenic contaminants, and the presence of growth factors (GFs) and other biological proteins can lead to undesirable cellular effects. b ∣ Synthetic scaffolds are highly tunable and chemically defined. The mechanical, physical and biological properties of these scaffolds can be modified to direct cellular response while eliminating undesirable matrix-induced effects.

Fig. 2∣. Advantages of synthetic scaffolds over Matrigel for cell culture, tissue engineering and organoid formation.

Synthetic alternatives to Matrigel provide a xenogenic-free, chemically defined and reproducible scaffold that can be tuned to guide cellular behaviour for a myriad of applications, including differentiation and organoid formation. The chemically defined nature of synthetic scaffolds also eliminates matrix-induced effects, providing a superior scaffold for toxicant and therapeutic screening assays.

Fig. 3∣. Comparison of Matrigel and synthetic scaffolds for stem cell differentiation and tissue engineering.

Unlike Matrigel, which is not tissue specific, synthetic scaffolds can be tuned (often through the addition of peptides) to provide specific biofunctionality to direct cell differentiation. The growth factors and other biologically active proteins in Matrigel lead to the generation of heterogeneous cell populations, whereas synthetic scaffolds generate pure populations of differentiated cells. In the context of in vivo delivery for tissue engineering applications, synthetic scaffolds can be delivered locally to the target site and be tuned to provide sustained mechanical support and biochemical instruction to transition from a cell-laden synthetic scaffold to neotissue. Conversely, the degradation of Matrigel is uncontrolled and its biofunctionality often leads to the formation of blood vessels. The potential for xenogenic contaminants in Matrigel or Matrigel-cultured cells prevents clinical application. Moreover, the handling of Matrigel in clinical settings is difficult owing to its gelation over a wide range of temperatures.

Fig. 4∣. Comparison of Matrigel and synthetic scaffolds for organoid assembly and preclinical tissue models.

a ∣ Matrigel scaffolds provide non-specific biochemical and mechanical signals for the spontaneous differentiation and self-assembly of cells into an organotypic model. The biological complexity of Matrigel leads to scaffold-induced effects, which affect the accuracy and reproducibility of preclinical models that rely on Matrigel-cultured cells. b ∣ Synthetic scaffolds have a chemically defined structure and the biological, mechanical and physical parameters can be tuned to guide organoid formation.