TISSUE ENGINEERING Polymers flex their muscles

Engelmayr and colleagues report the fabrication of a polymer-based, accordion-like honeycomb three-dimensional scaffold with anisotropic mechanical properties that resemble those of myocardium and promote the alignment of heart cells in a preferred orientation. Engelmayr propose an exciting modification of poly(glycerol sebcate) (PGS) using excimer laser microablation to integrate a preferred plane of flexibility into the scaffold materials. The resulting accordion-like honeycomb scaffolds are seeded with neonatal rat myocytes to generate contracting myocardial tissue constructs. One of the limitation in this issue is biocompatibility as PGS exerts an inflammatory response similar to co-polymers of poly(lactic acid) and poly(glycolic acid) but causes little fibrous tissue encapsulation after subcutaneous implantation. This technique is successfully used to generate autologous centimeter-scale contractile muscle under GMP regulations.