Light microscopy evaluation of polyurethane vascular grafts porosity by Sudan Black B staining

Abstract

SummaryIn small-diameter vascular grafts, the porosity of the internal surface plays an important role because it affects initial thrombus deposition and therefore the graft's patency. As well as many other studies reported in the literature we have carried out a study of the relationship between porosity and the manufacturing parameters of polyurethane (PU) grafts by standard scanning electron microscopy (SEM) analysis. However, SEM was not completely satisfactory for evaluating the 'sponge-like' uptake of water by the graft due to the unavoidable water loss and metal coating during preparation. In fact this preparation produces artefacts of the three-dimensional porous structure. To avoid this problem we investigated the possibility of observing the graft's internal surface through a stereomicroscope after it had absorbed water. We looked into a simple staining procedure which preferentially colours the PU graft fibres with respect to the void areas. After testing different kinds of stains, we eventually found that Sudan Black B, which usually stains for all kinds of lipid, turned out to be an excellent stain for the water-loaded PU grafts when diluted with ethanol. This staining procedure, coupled with a computerized image analysis system, allowed us to evaluate the degree of void and average void size of the graft internal surface and to correlate these data with graft density and manufacturing parameters.

In vivo evaluation of an elastomeric small‐diameter vascular graft reinforced with a highly flexible Nitinol mesh

“…Graft microgeometry was examined by Sudan Black staining with a procedure previously described . Briefly, graft samples were dipped in a staining solution (0.12% w/v in absolute ethanol) for 10 min and then rinsed in distilled water.…”

Development of a gelatin-based polyurethane vascular graft by spray, phase-inversion technology

“…Graft microgeometry was highlighted by Sudan Black staining with a previously described procedure [21]. The stained surfaces were observed by a stereomicroscope (SZH0, Olympus, Milano, Italy) connected to a digital camera and representative images were acquired at 40 × magnification.…”

“…SEM images were further processed using a computerized image analysis system (AxioVision Rel 4.6, Carl Zeiss, Jena, Germany). Briefly, circles were manually drawn following the perimeter of visible pores, and then the software calculated the average pores diameter [21].…”

Increased Adipogenesis in Cultured Embryonic Chondrocytes and in Adult Bone Marrow of Dominant Negative Erg Transgenic Mice

“…Scale bar: 100 µm. B. Lipid staining with Sudan black B (Merck) was used to evaluate lipid droplets within adipocytes according to Soldani et al [61] on section from femur of 40 week-old DN-Erg mice. Scale bar: 50 µm.…”