ABSTRACT
Across metazoans, collagen-based extracellular matrices (ECMs) play key roles in development, tissue homeostasis, and pathological states such as cancer and ™brosis. In vertebrates, there are at least 28 known types of collagen (Kadler et al. 2007), with each tissue type featuring a speci™c ECM composition and exhibiting exquisite structure intimately tied to tissue function. In order to understand how cells are integrated to build tissues and organs, and to potentially engineer such systems, methods to build and analyze realistic models of cells in a 3D ECM in vitro are essential. To date, studies of cell biology have been conducted primarily on 2D surfaces, o¹en in the absence of ECM molecules. —e construction of naturally derived 3D extracellular matrix materials provides platforms for studying cell biology in native-like microenvironments and for engineering replacement tissues. However, many 3D ECM in vitro culture models are not well de™ned in composition or structure, which poses challenges for both the engineering of tissues and the study of cell biology. Further, gels that consist of a limited number of ECM components do not fully recapitulate the complex compositions and structures of native tissue ECM microenvironments. Numerous studies have investigated ways to modulate the structure of collagen-based ECMs in vitro, allowing for experimental control over properties, such as mesh size, ™ber morphology, and ™ber alignment, in order to recreate the nano-to microscale structural, and thus functional properties of native tissues.
