The disclosure relates to a composition that is liquid at a temperature below the body temperature of a
mammal and that solidifies at or above the body temperature of the
mammal. The composition includes a thermally-desolubilizable
polymer interspersed with a polymeric component of
extracellular matrix and an encapsulated form of an amine compound (preferably an aminated component of
extracellular matrix) that is de-encapsulated in the body of the
mammal. The polymeric component is able to form covalent bonds with amine moieties in the aminated component, in one or more tissues in the body of the mammal, or both. Upon injection of a
liquid suspension of these components into the body of the mammal, the thermally-desolubilizable
polymer condenses, entrapping the polymeric component. The polymeric component binds covalently with a tissue in the body, and the aminated component end-caps the remaining reactive moieties of the polymeric component, forming a matrix at the site of injection. The disclosure also relates to uses of such compositions for forming a matrix on or within the body of a mammal. The compositions have a variety of uses, such as as bioadhesives, as sealants for ruptured tissues, as
drug or
imaging agent depots, or as mechanical cushions.