Alginate/calcium phosphate scaffolds with oriented, tube-like pores

Abstract

Porous and mineralised scaffolds are required for various applications in hard tissue engineering. Scaffolds with oriented tube-like pores facilitate homogenous cell seeding, a sufficient nutrient supply during cell culture (even in big constructs) and a fast vascularisation after implantation. The phenomenon of ionotropic gelation has been known since more than 30 years which describes that alginate forms gels with capillary-like pores when covered with solutions of di-or trivalent cations [1]. This technique has been used here to develop scaffolds with tube-like and regular pores from alginate/calcium phosphate composites and to stabilise them by mineralisation with hydroxyapatite from solution.

Binding of Topotecan to a Nicked DNA Oligomer in Solution

“…MR tubes (inner diameter 11.4 mm) were cleaned with ethanol before being coated twice with a thin layer of the alginate solution and the thin layer of alginate was dried onto the tubes in a 110 °C oven for 1 h. This ensured that the gel that formed during reaction between the metal ion solution and alginate solution adhered to the tube walls 5, 9. The coated tubes were then filled with the alginate solution and stored overnight to allow degassing.…”

“…Of medical interest is a mutant strain of P. aeruginosa which plays a role in cystic fibrosis by producing a particularly thick alginate gel. Alginate gels are also of interest as a biomaterial for drug delivery and tissue engineering applications 3–6…”

“…However, at higher ion concentrations (above 0.1 M ) and for some ions (copper in particular), internal structures described as capillaries will form as the gel reaction takes place 9, 10. These capillaries have been used for the development of scaffolding systems and research has shown that fine control of the microstructure of alginate gels is possible 3, 5, 6. However, the mechanism for the formation of these capillaries has not been completely explained.…”

Alginate/Nanohydroxyapatite Scaffolds with Designed Core/Shell Structures Fabricated by 3D Plotting and in Situ Mineralization for Bone Tissue Engineering

“…38 The plotted alginate and mineralized scaffolds presented here have significantly higher mechanical strength than those fabricated with low concentrated alginate by either 3D plotting or conventional methods. 24 There are many studies demonstrating the influence of surface properties of scaffolds on cell attachment and shape, 43−46 especially chemical composition and morphology. Surface characteristics strongly influence protein-binding ability, known to be one of the key factors for cell adhesion.…”

Novel Biomaterials with Parallel Aligned Pore Channels by Directed Ionotropic Gelation of Alginate: Mimicking the Anisotropic Structure of Bone Tissue

“…Al 2 O 3 (Weber et al, 1997) or even with the mineral phase of bone, hydroxyapatite (HAP) . The pore distribution and run was characterized by µCT in ceramic (Goebbels et al, 2002) or composite (Despang et al, 2005b) state. Since 2005/6, the anisotropic structures have been subject of research in the area of tissue engineering with human cells for hard tissue (Despang et al, 2005a, Dittrich et al, 2006 and vascularisation (Yamamoto et al, 2010), in in vitro and in vivo studies in rats for nerve regeneration and with murine embryonic stem cells opening opportunities for the formation of many types of tissue (Willenberg et al, 2006).…”