Abstract
The extracellular matrix (ECM) is a complex fibrillar network that couples a cell with its environment and directly regulates cells’ functions via structural, mechanical, and biochemical signals. The goal of this study was to engineer and characterize ECM-mimicking protein platforms with material properties covering both physiological and pathological (tumorous) tissues. We designed and fabricated three-dimensional (3D) fibrillar scaffolds comprising the two major components of the ECM, namely collagen (Col) and fibronectin (Fn), using a previously developed freeze-drying method. While scaffolds porous architecture and mechanics were controlled by varying Col I concentration, Fn deposition and conformation were tuned using varied immersion temperature and assessed via intramolecular Förster Resonance Energy Transfer (FRET). Our data indicate that all scaffolds were able to support various crucial cellular functions such as adhesion, proliferation and matrix deposition. Additionally, we show that, keeping the stiffness constant and tuning the conformation of the Fn layer used to coat the Col scaffolds, we were able to control not only the invasion of cells but also the conformation of the matrix they would deposit, from a compact to an unfolded structure (as observed in the breast tumor microenvironment). Therefore, these tunable scaffolds could be used as 3D cell culture models, in which ECM microarchitecture, mechanics and protein conformation are controlled over large volumes to investigate long-term mechanisms such as wound healing phases and/or vascularization mechanisms in both physiological and pathological (tumorous) microenvironments. These findings have implications for tissue engineering and regenerative medicine.
Highlights
Cells are known to sense and respond to the topography and mechanical properties of their substrates [1,2,3]
We report the fabrication of 3D collagen scaffolds with controlled mechanics, microarchitecture and protein contents prepared via an ice-templating method; these are capable of supporting 3D cell cultures in large volumes and for long cell culture times
To investigate the effect of Col concentration on scaffold pore size, pore distribution and mechanical properties, all scaffolds fabricated via ice-templating at −10°C with varied Col concentrations (0.5, 0.75, 1.0 and 1.25 wt%) were analyzed using scanning electron microscopy (SEM), Hg intrusion porosimetry and DMA, respectively
Summary
Cells are known to sense and respond to the topography and mechanical properties of their substrates [1,2,3]. Fn is critical to the deposition of collagen (Col) I based ECM [9] and its conformational changes serve as an indicator of increased tumor aggressiveness [10]. External forces, applied via atomic force microscopes and laser tweezers, have been used to modify the conformation of individual protein molecules on two-dimensional (2D) substrates [13, 14]. Such force-induced protein stretching/unfolding methods have limitations as they can hardly apply in threedimensional (3D) environments. No investigation focusing on the control of Fn conformation in 3D templates based on natural protein, such as collagen, has been reported
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
