These polymers do not have a true mammalian analog and exhibit a high application potential across many different regenerative medicine Paclitaxel human endothelial cells applications. The realization of clinical potential of these polysaccharides will be a long and challenging road, as the regulatory context of medical devices and advanced therapy medicinal products, in particular, are very demanding. The lack of industrial scale extraction and purification of many of these molecules remains an obstacle for their application development. In fact, a fundamental requirement for any clinical application will be related with development and validation of manufacturing methods. In some cases, the extraction route may not be a possible manufacturing strategy, as the scarcity of the raw materials, attainable purity levels or final cost may be incompatible with industrialization.

Synthesis of surrogate or close analog molecules may be, in some cases, the only cost effective approach. In spite of the manufacturing strategy adopted, the natural provenience and novelty of these materials imposes a strict control of their purity, stability and safety, which imply extensive and, above all, expensive studies. More than proving additional and or incremental benefits in discrete application contexts, the challenge ahead for any sulfated polysaccharide will be to gain its status as a new biomaterial. For that, sulfated polysaccharides will have to demonstrate outstanding application performance, scalable manufacturing, remarkable cost-benefit potential, while addressing a tangible market opportunity.

Acknowledgments The authors wish to acknowledge the financial support of ERDF through POCTEP Project 0330_IBEROMARE_1_P and Atlantic Area Project 2011-1/164 MARMED, as well as from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement KBBE-2010-266033 (SPECIAL project). Portuguese Foundation for Science and Technology is also gratefully acknowledged for fellowships of E.G.P., S.S.S. and T.H.S. Disclosure of Potential Conflicts of Interest Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed. Footnotes Previously published online: www.landesbioscience.com/journals/biomatter/article/22947
For many biomedical applications, there is need for porous implant materials.

Some of the many applications in which porous biomaterials are used include artificial blood vessels,1,2 skin,3,4 bone5,6 and cartilage7,8 reconstruction, periodontal repair9 and drug delivery systems.10 In the most basic sense, porosity is sought to promote new tissue formation by providing an appropriate surface to encourage cellular attachment and AV-951 an adequate space to host cells as they develop into tissue. However, recent studies have demonstrated how cells are highly sensitive to geometrical constraints from their microenvironment, which regulate tissue formation by affecting cell migration, proliferation, and also differentiation.