Tip 1: Tying a Muscle Fiber/Small Muscle to an ASI Force Transducer and Length Controller
Tying requires adding a short length of fine gauge hypodermic needle tubing to the force transducer and length controller. The fiber is then tied to these two needles using fine suture (10-0 monofilament nylon suture). See the attached photo of a small intact muscle tied to a force transducer and length controller. Neither the force transducer output tube nor the lever arm are visible in this photo but the researcher was using an Aurora Scientific model 400A force transducer and a model 318B length controller. In the photo the wire at the bottom is a platinum stimulation electrode and the needle at the top is a thermocouple.
The expected force generated by the fiber will determine the number of suture loops to use. This photo shows four on each end which was required to prevent slippage of this mouse lumbrical muscle. Note: whenever you tye an intact muscle you must ensure that no sutures are tied to the muscle tissue itself, only attach the muscle using the tendons.
Photo 1 Lumbrical Muscle Tied to 29 AWG Tubes
When tying permeabilized fibers, or even fiber bundles, it is more likely that you will only require 2 or 3 sutures per end.
Photo 2 Permeabilized Fiber Tied to 29 AWG Tubes
(photos courtesy of Muscle Mechanics Lab – University of Michigan)