Graft porosity

Porous synthetic vascular grafts Porosity allows connective tissue ingrowth into a wall of the prosthesis [54] ... 

As long as the pore diameters are large enough for easy entry and exit of reactant and product molecules, the catalyst porosity features do not have a significant influence on the epoxidation activity. In a comparison between two epoxidation catalysts obtained by grafting Ti( o-PrO )4 on MCM-41 and an amorphous silica gel, respectively, the former showed a lower activity (189). 

Porous materials may have a closed porosity, which lowers their density and can be varied to optimise their mechanical properties, as this is carried out for some kinds of vascular grafts. For such materials, surface morphology must fulfil same requirements as those fulfilled by compact materials. 

In this review we first summarize methods of synthesis of ECM analogs as graft copolymers. The modification of supermolecular structure (crystallinity, crosslink density, porosity) is then discussed. Finally, the relationships between polymer structure and biologic activity are summarized. 

Compared to the in situ polymerisation of a monolith, the grafting approach does not need re-optimisation of the protocol in order to obtain an appropriate porosity and flow properties for the monolith when monomer or template is changed. Moreover, the properties of the core materials are generally preserved and the imprint generated on the surface of the materials only requires a minimum amount of template and provides well-accessible recognition sites. 

Kusaba A, Fischer 3rd CR, Matulewski TJ, Matsumoto T. Experimental study of the influence of porosity on development of neointima in Gore-Tex grafts a method to increase long-term patency rate. American Surgeon 1981, 47, 347-354. 

Watanabe T. Experimental study on the influence of porosity on the development of the neointima in E-PTFE grafts. Nippon Geka Gakkai Zasshi 1984, 85, 580-591. 

Graft wall (fabric) porosity (<30 days after graft placement)... 

The simple way to cancel these two limitations appears to synthesise a material with a permanent porosity, allowing a good access of the grafted species in any kind of solvent. In addition, the presence of two or more methylene units between the heteroatom of the functional group and the phenyl ring of the polymer backbone would avoid the problem of the benzylic position. There are different ways to prepare a polymer supports having permanent porosity, but only some of them could be used for our purpose ... 

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