Abstract: One aspect of the present invention generally relates to methods of sealing a wound or tissue plane or filling a void splace. In a preferred embodiment, the wound is an ophthalmic, pleural or dural wound. In certain instances, the compositions used to seal the wound or tissue plane comprises a polyalkyleneimine. In a preferred embodiment, the polyalkyleneimine is polyethyleneimine. Treatment of the polyethyleneimine with a cross-linking reagent causes the polyethyleneimine polymers to polymerize forming a seal. In certain instances, the cross-linking reagent is a polyethylene glycol having reactive terminal groups. In certain instances, the reactive terminal groups are activated esters, such as N-hydroxy succinimide ester. In certain instances, the reactive terminal groups are isocyanates. In certain instances, the polyethyleneimine has a lysine, cysteine, isocysteine or other nucleophilic group attached to the periphery of the polymer.