A single-use syringe, comprising a barrel, and a first resilient unidirectionally-biased peripheral annulus formed inside the barrel； an upper plunger, having a dome shaped bottom mounted at a first end of the upper plunger, a first flange formed at a second end of the upper plunger with a second flange formed adjacent to it； a lower plunger having a second resilient unidirectionally-biased peripheral annulus formed near a top end of the lower plunger and a third resilient unidirectionally-biased peripheral annulus formed further inside the lower plunger, wherein a holding space is defined by a space between the second annulus and the third annulus, allowing the dome shaped bottom be inserted through the second annulus, held in the holding space, and pressed against the third annulus during a syringe unlocked state, and wherein a locking chamber is defined by a space between the third annulus and the lower plunger bottom end.
