Topotactic Fibrillogenesis of Freeze-Cast Microridged Collagen Scaffolds for 3D Cell Culture

Abstract

Type I collagen is the main component of the extra-cellular matrix (ECM). In vitro, under a narrow window of physico-chemical conditions, type I collagen self-assembles to form complex supramolecular architectures reminiscent of those found in native ECM. Presently, a major challenge in collagen-based biomaterials is to couple the delicate collagen fibrillogenesis events with a controlled shaping process in non-denaturating conditions. In this work an ice-templating approach promoting the structuration of collagen into macroporous monoliths is used. Instead of common solvent removal procedures, a new topotactic conversion approach yielding self-assembled ordered fibrous materials is implemented. These collagen-only, non-cross-linked scaffolds exhibit uncommon mechanical properties in the wet state. With the help of the ice-patterned micro-ridge features, Normal Human Dermal Fibroblasts and C2C12 murine myoblasts successfully migrate and form highly-aligned populations within the resulting 3D biomimetic collagen scaffolds. These results open a new pathway to the development of new tissue engineering scaffolds ordered across various organization levels from the molecule to the macropore, and are of particular interest for biomedical applications where large scale 3D cell alignment is needed such as for muscular or nerve reconstruction.

Type I Collagen-Fibrin Mixed Hydrogels: Preparation, Properties and Biomedical Applications

“…Varying physico-chemical parameters such as concentration, pH or salinity offers a wide variety of structures with tailored organization and mechanical properties [21][22][23][24]. Many processing methods, including most recent 3D printing, provide further tools to adapt the hydrogel features to a specific application [25][26][27][28]. Physical, chemical or enzymatic cross-linking [29,30] as well as incorporation of particles, including calcium phosphates, silica or carbon nanotubes, following a composite approach can also be undertaken to improve the mechanical properties of the hydrogels as well to increase their stability in water and slow down their biodegradation [31][32][33].…”

Redesigned Silk: A New Macroporous Biomaterial Platform for Antimicrobial Dermal Patches with Unique Exudate Wicking Ability

“…Given that the application of antimicrobial patches must reside and act in a humid environment, one of the central requirements that needs to be fulfilled by a prospective material is water insolubility. Unlike most biomaterials processing routes, ice templating is particularly useful to preserve the structural and molecular integrity of biopolymers [3] . This feature, commonly considered an advantage to shape temperature-sensitive systems, also means that the intrinsic properties of SF, such as its water solubility, are not modified during the process.…”

“…Devising new ways to shape biomaterials into controlled macroporous constructs, whose design principles rely often in reproducing the structural building block and composition found in natural materials, holds promise in dictating their functionalities in applications as diverse as drug delivery carriers, biomimetic membranes, and implants [2] . In this context, ice-templating (also known as freeze-casting) has evolved from a ceramics-oriented process devoted to the fabrication of lightweight materials to one of the most promising routes to fabricate aligned macroporous biomaterials from biopolymers [3][4][5][6] . The technique is based on a uniaxial thermal gradient that promotes the segregation of solutes and/or suspended particles induced by a growing ice front.…”

“…Upon sublimation these materials reveal the macroporous structure defined by ice. Ice-templating has been previously widely explored for the fabrication of biocompatible three-dimensional (3D) aligned scaffolds for tissue engineering applications [3,4,[7][8][9] in particular because of the scaffolds' ability to promote cell contact guiding.…”

Magnetic Field Alignment, a Perspective in the Engineering of Collagen-Silica Composite Biomaterials

“…While this may include biological or synthetic polymers [3], we focus here on type I collagen, which is of particular relevance for designing biomimetic ECMs as it is a major constituent of connective tissues [4,5]. Many different processes have been used to shape collagen while preserving its native conformation [6], including extrusion [7], aerosols [8], electrospinning [9] and freeze-drying technologies [10]. High magnetic field has also been used to control collagen alignment, as collagen fibrils orient perpendicularly to the field direction [11][12][13][14].…”