Method for efficiently producing β myosin heavy chain in cardiac muscle cells differentiated from induced pluripotent stem cells derived from Homo sapiens

A method for producing a β myosin heavy chain in cardiac muscle cells differentiated from human induced pluripotent stem cells, the method comprising:

• (a) supplying a liquid culture medium containing the cardiac muscle cells onto a substrate comprising a first electrode, a second electrode and insulative fibers on the surface thereof to coat a surface of the first electrode, a surface of the second electrode, and a region between the first electrode and the second electrode with the cardiac muscle cells;
• wherein
• at least a part of the insulative fibers is located between the first electrode and the second electrode in a top view of the substrate;
• and
• an angle formed between each of not less than 90% of the insulative fibers and an imaginary straight line which passes through both the first electrode and the second electrode is not more than ±20 degrees in the top view;
• (b) leaving the substrate at rest;
• (c) cultivating the cardiac muscle cells, while a pulse electric current is applied to the cardiac muscle cells through the first electrode and the second electrode;
• and
• (d) obtaining the β myosin heavy chain produced in the cultivated cardiac muscle cells.