Figure 1
Formation of electrically excitable tissue-engineered skeletal muscles at day 4.
(a) A representative peak twitch force using a single electric pulse (red line; voltage: 0.83 V/mm, width: 10 ms) and fusion of tetanus (blue line; voltage: 0.83 V/mm, width: 10 ms; frequency: 50 Hz, duration: 2 s) generated by the in vitro skeletal muscle tissue constructs. (b) The force-frequency diagram for the tissue construct. Electric stimulations (voltage: 0.83 V/mm, width: 10 ms) with frequencies of 0.5, 1, or 2 Hz were applied to the tissue construct and twitch forces were monitored. (c) The effect of pulse voltage on force production. Using a 10-ms pulse width, the voltage was incrementally increased (mean ± SD of three constructs). (d) The effect of pulse width on force production. Using a 0.5 V/mm voltage, the pulse width was incrementally increased (mean ± SD of three constructs). (e) The percentage of peak twitch force (%Pt) generated by the in vitro skeletal muscle tissues. To determine 100%Pt, peak twitch force was measured by using a single electric pulse at 0.83 V/mm and 10 ms and %Pt at each electric stimulation was determined by measuring the peak twitch force. %Pt increased proportionately within the range of electric pulses tested (voltage: 0.1–0.5 V/mm; width: 2–10 ms).
