The Heart of Nanotechnology

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Science  12 Feb 2010:
Vol. 327, Issue 5967, pp. 763
DOI: 10.1126/science.327.5967.763-c

Muscle cells in the heart must adopt specific orientations so that they can work together to produce strong contractile forces. The cells receive organizing cues from the surrounding extracellular matrix (ECM). In tissue culture, myocyte orientations are random in the absence of ECM, and large-scale patterning (on the order of 10 µm) of the substratum can instill an organized pattern of growth.

Kim et al. have used capillary lithography to create a synthetic extracellular matrix from polyethylene glycol hydrogel arrays, with grooves and ridges a few hundred nanometers tall and wide—a scale that may mimic the effect on cells of ECM fibrils in vivo. Although the rat ventricular myocytes sometimes spanned several ridges, they were sensitive to ridge spacing. The physical properties of the synthetic matrix influenced cell orientation, cell size, adhesion, and electrophysiological properties. Expression of the gap junction protein connexin 43, which supports intercellular communication, was also sensitive to variation in the spacing of the ridges. The authors note that the ability to synthesize such materials may be essential for engineering tissue-repair processes in medical applications.

Proc. Natl. Acad. Sci. U.S.A. 107, 565 (2010).

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