A medical device (100) comprising: a syringe barrel (110) that includes a side wall (114) having an inner surface (116) defining a chamber (118) for retaining fluid, an open proximal end (119) and a distal end (111) including a distal wall (112) with a tip (120) extending distally therefrom having an open conduit (122) in fluid communication with said chamber (118)； a piston rod (140) comprising a proximal end (119), a distal end (111) and a body (142) extending from the end (149) proximal to the distal end (141), in which the stem (140) of the plunger is disposed inside the chamber (118) and is movable in the proximal and distal direction inside the chamber (118)； a sealing gasket assembly disposed inside the chamber (118) and movable in the proximal and distal direction inside the chamber (118), in which the sealing gasket assembly forms a fluid tight seal with the inner surface (116) of the syringe barrel (110), a seal (160) that includes a distal face (174), a proximal end (169) and a body extending from the face (174) distal to the proximal end (169), in which the body extends from the face (174) distal to the proximal end (169) defining a cavity (166) of the seal and in which the seal includes a part (162) expandable adjacent to the proximal end (169) comprising a flexible wall (172) that expands the cavity (166) of the seal to create a vacuum inside the cavity (166) of the seal； and a porous part (190) comprising an inflatable polymer associated with the seal (160) to allow air to flow into the cavity (166) of the seal and prevent liquid from entering the cavity ( 166) of the sealing gasket, the piston rod (140) and the sealing gasket (160) configured to create a pressure difference between the cavity (166) of the sealing gasket and a part of the chamber (118) extending from the distal wall (112) and the distal face (174) of the seal assembly, characterized in that the porous part (190) comprises a selective barrier that defines a liquid penetration pressure
