Intracellular Ca²⁺ imaging for micropatterned cardiac myocytes

The patterning of cardiac myocytes on a micron scale (-5 pm) was achieved by microcontact printing of fibronectin onto a hydrophobically pretreated glass substrate. The patterned cardiac myocytes conjugated with each other by forming a gap junction, as judged from the synchronized Ca²⁺ transition over the pattern, and thus simultaneously contracted. The dynamic change of the Ca²⁺ concentration within the patterned tissue was analyzed quantitatively during successive contraction and relaxation using a Nipkow-type high-speed confocal microscope.