Figure 6
Young’s modulus mean values obtained from AFM measurements on neurons in different development stages (young, mature and aged) treated with Aβ40 or Aβ42.
Shallow deformation (below 0.2 nN) by a 15 μm spherical probe of the neuron soma produce indentations between 0.2 and 0.6 μm (less than 10% of the cell height). This condition is important for the validity of the Hertz model. Untreated neurons under different aging conditions have similar elasticity mean values, approximately 100 Pa, as calculated from the AFM force-indentation curves. The culture conditions appear to significantly alter the effect of Aβ on membrane elasticity. For 1- and 3-week-old neurons incubated in PNG media Aβ oligomers had different effects. Aβ42 softened the membrane in all neuronal preparations. The Young’s modulus of aged neurons incubated in NBN2 media was dramatically affected by both Aβ species, presenting a decrease of 30%. *p, **p < 0.0001, ***p = 0.06 by unpaired Student t-test) (each sample had more than 30 points). Error bars represent the standard error of the mean for each condition.
