PCL films of varying porosity influence ICAM-1 expression of HUVECs.

Here, we investigate the relationship between the expression of intercellular adhesion molecule-1 (ICAM-1) and the adhesion of human umbilical vein endothelial cells (HUVECs) on a poly-ε-caprolactone (PCL) film with micropores of different pore sizes. The results showed that surface hydrophilicity increased with larger pore sizes, while surfaces became less hydrophilic as the pore size decreased. The ability for adhesion and proliferation of HUVECs on surfaces with larger pore sizes was enhanced as compared with that of surfaces with smaller pore sizes or a flat film. Furthermore, levels of mICAM-1 were increased and sICAM-1 decreased as a function of increasing pore size. These findings demonstrate that film surfaces with larger pore sizes may promote cell adhesion and proliferation and lead to increases in expression of mICAM-1. Thus, we conclude that the pore size of the material's surface exerts a significant impact on the expression of adhesion molecules, the expression of which can represent an important new marker for investigating cell-surface adhesion and proliferation. Moreover, as elevated levels of sICAM-1 are associated with conditions such as inflammation, thrombosis, cerebral infarct and other diseases in vivo, it may serve as an early-warning risk marker when using medical biomaterials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2775-2784, 2016.

Mechanical and biocompatibility performance of bicomponent polyester/silk fibroin small-diameter arterial prostheses.

BACKGROUND: In this study, we fabricated prototype bicomponent polyester/silk fibroin small-diameter arterial prostheses using a specially designed narrow ribbon shuttle loom. METHODS: The 2-layered flat fabrics were then heatset on a mandrel to form tubes with a round cross section. RESULTS: The woven samples had a wall thickness between 0.23 mm and 0.29 mm and an inner diameter between 3.53 mm and 3.95 mm, depending on the yarn type and the weave structure. CONCLUSIONS: The bicomponent polyester/silk fibroin samples had superior bursting strength, circumferential strength and suture retention strength compared with a commercial small-diameter arterial prosthesis made from ePTFE. In addition, these prototype samples had greater suture retention strengths than a dog femoral artery, which indicates that they have adequate biostability for clinical use. While their amount of radial compliance was superior to that of the ePTFE commercial graft control, it did not match that of a natural artery. So there is still a need for future improvement in compliance. All of the woven prototypes had water permeability values between 26 and 180 ml/(cm(2)*min), which confirms that none of these arterial prostheses needs to be preclotted at the time of implantation. The biocompatibility of the woven prototypes was evaluated using porcine endothelial cells and an MTT assay. Their cytocompatibility was found to be superior to the ePTFE commercial control, and the level of cell attachment was observed to increase on these prototypes woven with a higher silk fibroin content.

Surface Modification and Characterisation of Silk Fibroin Fabric Produced by the Layer-by-Layer Self-Assembly of Multilayer Alginate/Regenerated Silk Fibroin.

Silk-based medical products have a long history of use as a material for surgical sutures because of their desirable mechanical properties. However, silk fibroin fabric has been reported to be haemolytic when in direct contact with blood. The layer-by-layer self-assembly technique provides a method for surface modification to improve the biocompatibility of silk fibroin fabrics. Regenerated silk fibroin and alginate, which have excellent biocompatibility and low immunogenicity, are outstanding candidates for polyelectrolyte deposition. In this study, silk fabric was degummed and positively charged to create a silk fibroin fabric that could undergo self-assembly. The multilayer self-assembly of the silk fibroin fabric was achieved by alternating the polyelectrolyte deposition of a negatively charged alginate solution (pH = 8) and a positively charged regenerated silk fibroin solution (pH = 2). Finally, the negatively charged regenerated silk fibroin solution (pH = 8) was used to assemble the outermost layer of the fabric so that the surface would be negatively charged. A stable structural transition was induced using 75% ethanol. The thickness and morphology were characterised using atomic force microscopy. The properties of the self-assembled silk fibroin fabric, such as the bursting strength, thermal stability and flushing stability, indicated that the fabric was stable. In addition, the cytocompatibility and haemocompatibility of the self-assembled silk fibroin fabrics were evaluated. The results indicated that the biocompatibility of the self-assembled multilayers was acceptable and that it improved markedly. In particular, after the self-assembly, the fabric was able to prevent platelet adhesion. Furthermore, other non-haemolytic biomaterials can be created through self-assembly of more than 1.5 bilayers, and we propose that self-assembled silk fibroin fabric may be an attractive candidate for anticoagulation applications and for promoting endothelial cell adhesion for vascular prostheses.