Scaffold stiffness

Taken together, these results support the fact that both neutrophils and macrophages are highly sensitive to biomechanical environment dictated by scaffold stiffness and a design strategy for interfering with scaffold stiffness can be an effective approach to modulate innate immune response. 

Brona et al [18] have tested the relationship between alginate concentration, scaffold stiffness and viscoelastic behavior mimics that of the NP. The effect of variations in scaffold stiffness had been investigated on the expression of ECM molecules specific to NP. The sample discs were prepared of various concentrations of alginate (1 6%) by two different methods i.e. diffusion and in situ gelation. They found that the alginate can mimic the viscoelastic properties of the NP and capable of preserving the biosynthetic phenotype of NP cells. 

Marelli B, Ghezzi CE, Mohn D, Stark WJ, Barralet JE, Boccaccini AR, et al. Accelerated mineralization of dense coUagen-nano bioactive glass hybrid gels increases scaffold stiffness and regulates osteoblastic function. Biomaterials 2011 32 8915-26. 

For fibrous PU scaffolds, the mechanical environment is much more complex than 2D polyacrylamide since the scaffolds are porous, fibers are distributed within the constructs, and cells are attached to single fibers. As a result, the stiffness characteristics for both single fibers and scaffolds may have an impact on stan cell differentiation. We recently studied the effects of PU scaffold stiffness at small and large strains (before and after aUgmnent of fibers, respectively) and single fiber stiffness on cardiac differentiation of cardiosphere-derived cells (CDCs). The single fiber stiffness was... 

Levy-mishali, M., et al., 2009. Effect of scaffold stiffness on myoblast differentiation. Tissue Engineering. Part A 15 (4), 23-27. 

One of the most difficult challenges in tissue engineering is the vascularization of engineered constructs. A recent paper described the development of a scaffold that incorporated silk fibroin fibers into a salt-leached sponge made of poly(D,L-lactic acid) (PDLLA) (Stoppato et al., 2013). The addition of silk fibroin fibers to the PDLLA salt-leached sponge increased the scaffold stiffness and heightened its capacity to support endothelial cells in vitro, and the in vivo perfusion revealed a faster vascularization of the composite scaffolds. 

Fabiilli ML, Wilson CG, Padilla F, Martfn-Saavedra FM, Fowlkes JB, Franceschi RT [2013]. Acoustic droplet-hydrogel composites for spatial and temporal control of growth factor delivery and scaffold stiffness. Acto Biomater, 9,7399-7409. 

In order to develop a tissue-engineered heart valve, a group at Children s Hospital in Boston evaluated several synthetic absorbable polyesters as potential scaffolding materials for heart valves. Unfoitu-nately, the most synthetic polyesters proved to be too stiff to be function as flexible leaflets inside a tri-leaflet valve. " In the late 1990s, a much more flexible PHAs called poly-3-hydroxyoctanoate-co-3-hydroxyhexanoate (PHO) was used as the scaffold material for the valve leaflet, and then the entire heart valve. ... 

Adamantane can be used to construct peptidic scaffolding and synthesis of artificial proteins. It has been introduced into different types of synthetic peptidic macrocycles, which are useful tools in peptide chemistry and stereochemistry studies and have many other applications as well. Introduction of amino acid-functionalized adamantane to the DNA nanostmctures might lead to construction of DNA-adamantane-amino acid nanostmctures with desirable stiffness and integrity. Diamondoids can be employed to constmct molecular rods, cages, and containers and also for utilization in different methods of self-assembly. In fact, through the development of self-assembly approaches and utilization of diamondoids in these processes, it would be possible to design and constmct novel nanostmctures for effective and specific carriers for each dmg. 

Lee, C. R., Grodzinsky, A. J., and Pector, M. (2001). The effects of cross-linking of collagen-glycosaminoglycan scaffolds on compressive stiffness, chondrocyte-mediated contraction, proliferation and biosynthesis. Biomaterials 22,3145-3154. 

Raman spectroscopy can be used for live, in situ, temporal studies on the development of bone-like mineral (bone nodules) in vitro in response to a variety of biomaterials/scaffolds, growth factors, hormones, environmental conditions (e.g. oxygen pressure, substrate stiffness) and from a variety of cell sources (e.g. stem cells, FOBs or adult osteoblasts). Furthermore, Raman spectroscopy enables a detailed biochemical comparison between the TE bone-like nodules formed and native bone tissue. Bone formation by osteoblasts (OB) is a dynamic process, involving the differentiation of progenitor cells, ECM production, mineralisation and subsequent tissue remodelling. 

Another interesting approach is to use nanofiber scaffolds as a crystallization matrix to mimic biological composites. Xia and coworkers were able to produce meshes with a gradient of calcium phosphate content to mimic the tendon-to-bone insertion site [206], The variation in composition led to an interesting spatial gradient in stiffness of the scaffold. This was also reflected in an activity gradient of seeded mouse preosteoblast cells. 

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