Abstract: A method for preparing a powdered extracellular matrix material is described. A particulate extracellular matrix material wherein at least 90% of the particles detectable by laser diffraction are about 420 microns or less. A particulate extracellular matrix material is also provided wherein at least 50% of the particles detectable by laser diffraction are about 210 microns or less.

Abstract: Methods for grafting unmodified PEO or any other water-soluble polymers to the surfaces of metals and glasses to form biocompatible surfaces having low protein affinity is provided. One technique includes the steps of: (a) providing a support member having a plurality of hydroxyl or oxide groups attached to a surface of said support member; (b) exposing said surface to a silane coupling agent to cause the silane coupling agent to form a silane layer that is covalently bound to the surface wherein the silane layer comprises a plurality of vinyl groups; and (c) exposing the silane layer to a hydrophilic polymer and causing the silane layer to react with the hydrophilic polymer to covalently bond to the silane layer. Exposure of the silane layer to .gamma.-radiation to induce grafting with low radiation to induce grafting of the hydrophilic polymer to the silane layer.