This paper presents a mechanical cell lysis microfluidic chip with an ultra-sharp nano-blade array fabricated by simple and cost effective crystalline wet etching of (110) silicon. The ultra-sharp nano-blade array is simply formed by the undercutting during the crystalline wet etching process. The sharpness of the silicon nano-blade is less than 10 nm after the undercutting. EL4 mouse T-lymphoma cells are used for the demonstration of the mechanical lysis chip, and the cells are easily disrupted by the silicon nano-blade array without helping of additional reagents or electrical sources. The time-resolved observation of the mechanical cell lysis shows that the developed silicon nano-blade array is enough to easily disrupt the cell membrane even at very low flow rate of 0.7 ????/hr.