Bioactivation of knitted cellulose scaffolds by strontium

Abstract

Strontium has attained increasing interest in the treatment of osteoporosis due to its anabolic as well as antiresorptive activity. Knitted cellulose scaffolds with a porosity suitable to promote bone tissue ingrowth and vascularisation were doped with SrCO 3 . The in vitro bioactivity of the modified scaffolds was proven by formation of hydroxyapatite during exposure to simulated body fluid. The Sr-release kinetics during static exposure to simulated body fluid is dominated by an accelerated Sr-release in the initial state followed by a reduced release corresponding to a diffusion controlled rate. Microstructural analyses indicate that initially precipitated SrCO 3 transforms to Sr x Ca 1-x CO 3 solid solutions that subsequently serve as a template for the precipitation of bone like carbonated hydroxyapatite under conditions simulating the inorganic part of the human blood plasma.

In vivo Performance of Osteoactivated Cellulose‐Based Scaffolds in Bony Critical‐Size Defects

“…This finding correlates with previous evaluations which showed an in vitro osteoactivity of sodium silicate and strontianite coatings. [11,22,59] Immunohistochemical observations highlighted the ingrowth of insular osteocalcin-positive cells between loose cellulose monofilaments in all tested surface 90 days after surgery. For an osseous ingrowth into a porous implant the pore size of an interconnective porosity plays a fundamental role.…”

“…[15] The strontium concentration of sample SS-Sr amounts to 5 AE 1 Â 10 À6 g g À1 scaffold. For the direct coating with strontianite, SrCO 3 , the scaffolds were immersed in a 100 8C boiling 1:1 mixture of oxalic acid and hydrochloric acid and subsequent in a saturated Sr(OH) 2 solution ( P -Aldrich, Taufkirchen, Germany) according to Brandt et al [11] . These scaffolds (Sr) were loaded with 13 AE 3 mg Sr/g cellulose precipitated as strontium carbonate on the cellulose fibers.…”

“…These scaffolds (Sr) were loaded with 13 AE 3 mg Sr/g cellulose precipitated as strontium carbonate on the cellulose fibers. [11] All scaffolds were sterilized by gamma sterilization. The dissolution of the sodium silica gel and the formation of a Ca/P-phase during in vivo experiments were characterized by scanning electron microscopy (SEM) (Quanta 200, FEI, Eindhoven, Netherlands) equipped with an energy dispersive X-ray analysis system (EDX) (INCA x-sight, Oxford Analytical Instruments, UK) to determine the elemental composition.…”

“…[10] As recently described by Brandt et al, osteoactive surfaces can be generated by the modification of cellulose knits with strontianite (strontium carbonate). [11] Strontium (Sr), a trace element, with metabolic effects on bone in vivo is widely used for the treatment of osteoporosis. Its stimulating effect on the replication of osteoblastic cells in vitro and on bone formation in vivo has been demonstrated in various studies.…”

Application of heparinized cellulose matrices for substrate-mediated bFGF peptide and transgene delivery to stimulate cellular proliferation

“…Specifically, cellulose's biocompatibility is well recognized in the fields of biomaterials and tissue engineering (Miyamoto et al 1989;Martson et al 1998;Tate et al 2001). Because the mechanical properties of cellulose can be engineered to match those of hard and soft tissues, research has focused on using cellulose and its derivatives as wound-healing and tissue-engineering scaffolds to facilitate skin, cartilage, and bone regeneration and as substrates to prepare functional cardiac cell constructs and blood vessels (Martson et al 1998;Tate et al 2001;Czaja et al 2007;Cai and Kim 2010;Schumann et al 2009;Brandt et al 2008;Muller et al 2006;Entcheva et al 2004).…”