Sealant for medical purposes; medical preparations, namely, hydrogel sealants for dural repair during surgery; in situ polymerizing hydrogel-based medical preparations, namely, sealant preparations for tissue sealing and space filling; surgical sealant; surgical sealant preparations; biodegradable surgical sealant; polymer precursors that, when combined, form an in situ polymerizing hydrogel used as a surgical sealant in surgical procedures; surgical sealant for use in dural repair during sur...