WPI offers several muscle tester platforms, including the:
SI-CTS200 –Cell Tester for experiments on single cells and small muscle tissues
SI-MT –Basic Muscle Tester for most muscle experiments
SI-MKB –Comprehensive Muscle Plaftorm
These systems include a Signal Conditioning Amplifier System which is
the electronic component of the system. It is configured for a
researchers individual needs and comes with the modules a researcher
chooses. The amplifier system can accommodate up to eight channels.
Current available SI-H modules include:
SI-BAM21-LCB –Optical Transducer Amplifier
SI-AOSUB –Anti-Oscillation Unit
SI-MOTTEST –Linear Motor Controller
SI-TCM2 –2-Channel Temperature Controller
SI-SARCAM –Sarcomere Spacing Module
SI-COLU –Constant Load Unit (In the future this could be a module, but for now, it is a standalone unit.)
powers the force transducer and converts the output of the transducer
to an amplified analog voltage that is proportional to the force applied
to the transducer. The output signal can be multiplied by a factor of
1, 2, 5 or 10 to provide better resolution for a minimal change in
Each force transducer has a resonance frequency at which it vibrates. The SI-AOSUB, when properly tuned to that resonance frequency, removes the resonance noise from the output signal of SI-BAM21-LCB transducer amplifier. An SI-AOSUB is necessary when a linear motor is used.
When a linear motor is required, this module powers the motor and
provides an output indicating the actual motor position. It connects to
an analog to digital converter output of the data acquisition system
(like LabTrax 8/16) to control the waveform and timing for the motor
control. The output connects with an analog input of the data
acquisition system to monitor the sensor feedback from the motor.
When temperature control is required, the SI-TCM2
is used. It can control two cuvettes simultaneously, using digital
control to maintain a constant temperature. It has both high and low
alarm warnings which can be user defined.
Sarcomere spacing measurement requires a system with an optical cuvette
(cuvette with a window). A laser passes through the muscle, and the
diffracted light is captured with a CCD camera. By monitoring the
diffraction pattern, the length of the sarcomeres can be calculated.
When a laser light is shined through the muscle fibers, the light is
diffracted in a pattern, which is determined by the spacing between the
muscle fibers (sarcomeres). Because of the sarcomere structure, the
refraction pattern looks similar to placing a grating in front of the
light source. In other words, the monochromatic light (from the laser)
passing through a muscle preparation is diffracted corresponding to the
distance of the grating, also called the grating constant.
As the light shines through the muscle fiber, the sarcromeres diffract the light in a pattern.
Constant Load Module
It is often important to maintain a constant sarcomere length rather
than keep the total length of the preparation constant during an
isometric contraction. Even though the distance between the ends of the
muscle is kept constant, the muscle contraction causes an internal
shortening of the sarcomeres of the muscle. In order to get a true
isometric muscle contraction, the sarcomere length must be kept constant
during the contraction. For this purpose the output signal of the
camera (SI-SARCAM) can be fed into the feedback controlling the linear motor position using the SI-COLU. The feedback system controls the linear motor so that the sarcomere length is held constant.
Click the thumbnail to see a larger image of the Muscle Tester (left), MKB System (center) or the Cell Tester (right).
For basic muscle physiology information, see Muscle Physiology Basics.
For more information on the Sarcomere Spacing Module, see Sarcomere Spacing.
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