Ionic solutes impact collagen scaffold bioactivity
Journal of Materials Science: Materials in Medicine
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Pawelec, K., Husmann, A., Wardale, R., Best, S., & Cameron, R. (2015). Ionic solutes impact collagen scaffold bioactivity. Journal of Materials Science: Materials in Medicine, 26 https://doi.org/10.1007/s10856-015-5457-8
Within tissue engineering, collagen scaffold architecture is key for determining the biological activity of a scaffold [1, 2]. The architecture is defined by the scaffold isotropy, whether it possesses pores with inherent directionality or is purely isotropic, and by the pore size. Both architectural features can be modified using ice-templating techniques, which are controlled by the crystallization of ice within an aqueous solution . Scaffold anisotropy is determined at nucleation, while the final pore size is linked to crystal growth and annealing [4, 5]. Ice nucleation and growth are sensitive to many factors, and literature has focused on altering set freezing protocols and mold design [1, 5]. In addition to these factors, ice crystallization is also sensitive to the amount and type of solutes present . Solutes, such as sucrose and salts, slow ice crystal growth as their concentration in solution increases [6, 7]. Macromolecular solutes also decrease the ice growth rate as the concentration and the polymer molecular weight increase, an effect largely independent of viscosity . Collagen slurry incorporates both types of solutes, consisting of insoluble collagen fibrils suspended within an aqueous solution. In practice, increasing collagen concentration within slurries leads to decreased pore size . However, the composition of the aqueous solution and how it affects collagen slurry behavior, scaffold structure, and bioactivity has not been studied. It was hypothesized that the structure collagen scaffolds could be modified with the addition of solutes. Two solutes were chosen: sodium chloride (NaCl), which is known to impact collagen structure and ice formation, and sucrose, which is a well studied non-ionic solute used as a model system to understand ice growth kinetics [6, 9]. Four suspensions of 1 wt% collagen were compared: no additives, 0.5 wt% sodium chloride (NaCl), 0.5 wt% sucrose, and 5 wt% sucrose, and the biological activity was tested in vitro using chondrocytes.
The authors gratefully acknowledge the financial support of the Gates Cambridge Trust, the Newton Trust, NIHR, and ERC Advanced Grant 320598 3D-E. A.H. holds a Daphne Jackson Fellowship funded by the University of Cambridge. Also, the authors thank Dr. S. Butler for help with the rheological measurements.
European Research Council (320598)
External DOI: https://doi.org/10.1007/s10856-015-5457-8
This record's URL: https://www.repository.cam.ac.uk/handle/1810/247229