Apparatus for sealing a puncture communicating with a blood vessel includes a porous carrier formed from lyophilized hydrogel or other material. The plug may include at least first and second hydrogel precursors and a pH adjusting agent carried by the porous carrier in an unreactive state prior to exposure...http://www.google.co.uk/patents/US7335220?utm_source=gb-gplus-sharePatent US7335220 - Apparatus and methods for sealing a vascular puncture
