SEM micrographs of porcine collagen membranes.

(A)-(D) show different magnifications (200x to 10,000x) of one sample obtained from the PL. The observed smooth surface morphology of PL is also detectable in PE and on the cranial face of CT. (E)-(H) show micrographs obtained from the smooth side of SIS. (I)-(L) are images obtained from the rough side of SIS, and (M)-(P) depict the magnified micrographs from the peritoneal (i.e., caudal) side of CT. The caudal side clearly shows circular discontinuities (arrows), whereas the cranial side does not (https://doi.org/10.6084/m9.figshare.7082999). (Q) High magnification of fibril bundles reveals the typical periodic banding pattern of collagen fibrils. (R) Collagen fibrils showing right-handed helical grooves (arrows) are occasionally found in all the membrane types.