Assessment of contractility in osteoblastic cells

There currently exists evidence that bone cells can both apply and respond to mechanical changes to their underlying substrates. This investigation utilized an osteoblast-like cell line (MC3T3 cells) on a collagenous substrate to determine if contraction could be observed during a twenty-two hour incubation period. The contraction was measured using a cell-force monitor developed at MIT. This device uses the change in length of the matrix, measured as a voltage difference, to determine the contraction relative to a baseline. Two matrices were used, here referred to as matrices A and B. Four samples from each were used to obtain mean baseline voltages (A:0.1127±0.0269 V, B:0.1057±0.0050 V.) For the experimental cell-seeded runs, only one valid sample from matrix A was obtained with a maximum voltage of 0.1838 V, and two samples were averaged for matrix B to 0.1553±0.0045 V. While the sample set is not large enough to make statistical comparisons, the mean contraction for the cell-seeded runs does appear to be significantly greater than the baseline values, indicating that MC3T3 cells are capable of short-term contraction. This work is continuing with characterization of the substrate to enable conversion of the measured voltage to applied force. Future work will include investigations into the mechanisms of this cellular contraction.