((Subscript[V, pyramid])=((0.2   mm×0.2   mm×0.4   mm)/3)=0.0053   (mm^3)(Subscript[V, rectangle])=0.2   mm×0.2   mm×0.4   mm=0.016   (mm^3))}  0.0213   (mm^3)=0.0213   ul   volume/Needle   Tip