Continuing the failure force study, the effect of
microneedle diameter was assessed by preparing
needles with different base diameters (100 and 200
Am) at constant tip diameter of 25 Am and length of
700 Am. As shown in Fig. 9(B), the failure force
increased with base diameter. This dependence is
expected, because the critical buckling load is
theoretically known to increase as a strong function
of column diameter [43]. Again, safety margins
greater than unity are predicted in both cases