A membrane for implantation into a patient includes a first layer and a second layer. The first layer has oppositely disposed outer and inner first layer surfaces. The second layer has oppositely disposed outer and inner second layer surfaces. The second layer is at least partially attached to the first layer with the inner first and second layer surfaces adjacent one another. The inner first and second layer surfaces are resistant to biological tissue ingrowth and the outer first and second layer surfaces are conducive to biological tissue ingrowth.