A sealant is provided for sealing a puncture through tissue that includes an elongate first section including a proximal end, a distal end, and a cross-section sized for delivery into a puncture through tissue, and a second section fused to and extending from the distal end of the first section. The first section may be formed from a freeze-dried hydrogel that expands when exposed to physiological fluid within a puncture. The second section may be formed from a solid mass of non-freeze-dried, non-crosslinked hydrogel precursors, the precursors remaining in an unreactive state until exposed to an aqueous physiological, whereupon the precursors undergo in-situ crosslinking with one another to provide an adhesive layer bonded to the first section. Apparatus and methods for delivering the sealant into a puncture through tissue are also provided.
