Accordion-Like Honeycombs for Tissue Engineering of Cardiac Anisotropy

Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-330 Cambridge, Massachusetts 02139, USA.
Nature Material (Impact Factor: 36.5). 12/2008; 7(12):1003-10. DOI: 10.1038/nmat2316
Source: PubMed


Tissue-engineered grafts may be useful in myocardial repair; however, previous scaffolds have been structurally incompatible with recapitulating cardiac anisotropy. Here, we use microfabrication techniques to create an accordion-like honeycomb microstructure in poly(glycerol sebacate), which yields porous, elastomeric three-dimensional (3D) scaffolds with controllable stiffness and anisotropy. Accordion-like honeycomb scaffolds with cultured neonatal rat heart cells demonstrated utility through: (1) closely matched mechanical properties compared to native adult rat right ventricular myocardium, with stiffnesses controlled by polymer curing time; (2) heart cell contractility inducible by electric field stimulation with directionally dependent electrical excitation thresholds (p<0.05); and (3) greater heart cell alignment (p<0.0001) than isotropic control scaffolds. Prototype bilaminar scaffolds with 3D interconnected pore networks yielded electrically excitable grafts with multi-layered neonatal rat heart cells. Accordion-like honeycombs can thus overcome principal structural-mechanical limitations of previous scaffolds, promoting the formation of grafts with aligned heart cells and mechanical properties more closely resembling native myocardium.

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    • "The SILICOMB features a zero-ν behaviour by using a geometry inspired to the tessellation of the β-cristobalite lattice [29] [30]. One example of application of ZPR honeycombs with accordion-like honeycomb microstructures is biomedical scaffolds [31], and in the field of morphing aircraft flexible sandwich structures with cellular cores and flexible face sheets have been proposed as a promising solution for morphing skins [23] [32] [33]. ZPR honeycombs have been used in flexible skins undergoing one-dimensional spanwise morphing [22] [23] [32] [33] and have also demonstrated their potential in planar morphing applications [34]. "
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    • "Aligned scaffolds exhibited highest anisotropy under tensile loading with an anisotropy ratio T (V, 10) /T (H, 10) of 7.4. This ratio is at least two-fold higher than the anisotropy ratio reported previously for porous accordion-like honeycomb scaffolds (Engelmayr et al., 2008). A parallel to this behavior can also be drawn with aligned and random electrospun fibers. "
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