Second trial of the Mosquito on a real sample

posted Nov 28, 2012, 4:23 PM by Sensorica Group   [ updated Nov 29, 2012, 11:52 AM by Tiberius Brastaviceanu ]
After our last group meeting on Tuesday 27 Nov, 2012 (meeting notes - members only) we accelerated the pace of Philippe's project. The deadline is fast-approaching and we need to allocate more resources to this project.

There are two important sets of experiments going on in parallel:
  1. The biological test, i.e. using the Mosquito for the first time on real muscle samples, starting from a stripe of muscle down to a single cell. Ivan is in charge.
  2. Perform characterization measurements on the Mosquito and on different displacement force transducers. Tibi and James are in charge.
Jonathan now is finishing a new Mosquito using the all-fiber modular design. It should probably be in Phil's lab by the end of the week. The pic below shows 4 printed PCB boards.

boards for the new Mosquito made by Jonathan

In the mean time,
Tibi has installed the Mosquito Demo (based on the LabJack) in the lab to advance the biological tests. Tibi also finished a new LabView program to drive Jame's circuit for muscle cell stimulation. The entire stimulation system was successfully tested with the program and monitored on the oscilloscope. The screenshot below shows a stimulation signal on the front panel of the program. (Jame's circuit is driven by an NI_DAQ card, which is driven by the LabView program).

The Stimulator - a LV program that works with James muscle cell stimulation circuit.

The goal of the day was to measure an actual contraction of a diaphragm muscle stripe collected at 10 am in the morning. Unfortunately, the cells could not survive until 6pm in the afternoon. The picture bellow shows the muscle stripe hold in place by two polymer open rings, which in turn rest on 2 hooks that are attached to the Mosquito transducer (on the left) and to a glass needle (on the right). See more pictures at the end this page.

Muscle sample in the bath, The bath has temperature control system and electrical stimulation electrods.

This new solution to attach the sample to the force transducer was tested by puling on the sample and measuring the force with the Mosquito. In technical terms, this is also called measuring the passive tension (when the muscle is NOT activated), The picture below shows the passive stretch Mosquito trace.

passive stretch of a cardiac muscle - showing that the sample attachment to the Mosquito is good.

See more pictures of the system taken today.