An artificial cell membrane that has enhanced surface and mass transport properties, which can be used in implantable devices.
Several approaches have been proposed for improving the biocompatibility of biomaterials useful in medical applications. Many of these methods, however, have the disadvantage of being nonpermanent systems in that the surface coating is eventually stripped off or leached away. Membranes, as self-organizing noncovalent aggregates, offer a model for molecular engineering in which the constituent members can be controlled, modified, precisely defined, and easily assembled. During the past decade, phospholipids differing in chemical composition, saturation, and size have been utilized as building blocks in the design of a variety of structures of complex geometry. Lipid-based cylinders, cubes, and spheres have all found applications in both drug delivery and as templates for composite molecularly engineered structures.
Dr. Chaikof's group has developed a biocompatible biomaterial (or biological component) that comprises a membrane mimetic surface that covers a substrate, which is a hydrated substrate such as a hydrogel. The hydrated substrate may contain drugs for delivery to a patient through the membrane-mimetic film or may be made up of cells, such as islet cells for transplantation. The surface may have bioactive molecules or moieties exposed thereon for binding to target molecules in vivo, for modulating host response when implanted into a patient e.g., the surface may be antithrombogenic or anti-inflammatory, and the surface may have pores of selected sizes to facilitate transport of substances through the material. There may also be an optional hydrophilic cushion or spacer between the substrate and the membrane-mimetic surface so that transmembrane proteins may extend from the surface through the hydrophilic cushion. This mimics the structure of cells that are naturally equipped with transmembrane proteins. The biological component of this invention provides an alkylated layer directly beneath the membrane-mimetic surface to facilitate bonding to the surface.