A wound closure device (200) includes a filamentary element (202) having a proximal end (206) and a distal end (210) and a plurality of barbs (204) extending outwardly from the filamentary element. Each barb has a base (230) connected with the filamentary element a tip (232) spaced from the base and an outer edge (234) that extends between the base and the tip. The outer edge includes a first section (242) having a concave surface that extends between the base and a transition point (246) of the barb and a second section (244) having a convex surface that extends between the transition point of the barb and the tip of the barb. The outer edge transforms from the concave surface of the first section to the convex curve of the second section at the transition point of the barb. The tip of the barb has a convexly curved surface facing the distal end of the filamentary element. The unique dual radius shape of the outer edge of the barbs and the tips of the barbs minimizes resistance when the filamentary element is pulled in a first direction through tissue and maximizes resistance to movement when the filamentary element is pulled in an opposite second direction through tissue for holding the wound closure device stationary.
