Figure 2.

A. Graphic design of 0.8 mm octagonally-serrated, hollow needle. Trailing edge and arcuate bottoms are similar to quad needle in Figure 1, though individual points are closer to one another, with decreased angles for EDM cutting. Tip length is approximately 0.5 mm before coalescence. B. SEM image of 3D-CNC prototype octagonal needle. Minor blemishes can be seen along the needle shaft, but needle tips appear symmetric and closely resemble 2A.