Comparison of chitosan apatite composites synthesized by different methods

Abstract

This article presents some results concerning chitosan apatite composites obtained by two different methods. First method is based on phosphorylation, calcification and soaking in different calcium phosphate growth media (1.5 × SBF (simulated body fluid), Ca‐PTris (calcium phosphorous tris) and the second method is based on mixing of calcium deficient apatite powder with a chitosan solution. This research is focused on studying and understanding the effect of using different methods on Ca:P ratio of composites. The Ca:P ratio of composites formed in 1.5 × SBF are closer to that of bone when compared with the Ca:P ratio of composites formed in Ca‐PTris solution and Ca:P ratio of composites formed by mixing of calcium deficient apatite powder with a chitosan solution. The Ca:P ratio of the composite (1.75) immersed in 1.5 × SBF for 35 day is similar to the theoretical value of hydroxyapatite (1.67) and equal to the theoretical value of human bone (1.75). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Guar-Based Injectable Thermoresponsive Hydrogel as a Scaffold for Bone Cell Growth and Controlled Drug Delivery

“…The initial Ca/P ratio in HPG- g -PNVCL/n-HA/DVS before SBF immersion (day 0) was 0.83 ( Figure 8 b), so the initial scaffold was a calcium-deficient apatite-like biocomposite, because in stoichiometric HA, the Ca/P ratio is 1.67. 60 However, we found the deposition of apatite-like particles (and particle aggregates) on the HPG- g -PNVCL/n-HA/DVS scaffold surface after immersion in SBF for 7 and 14 days. These deposits were caused by the initiation of apatite nuclei on the scaffold surface, which produced crystals by absorbing more calcium (Ca 2+ ) and phosphorous (PO 4 3– ) from the SBF, thus displaying bioactivity.…”

“…Because of the absence of n-HA, the HPG- g -PNVCL scaffold did not exhibit apatite-like formation (Ca/P ratio = 0; Figure a). The initial Ca/P ratio in HPG- g -PNVCL/n-HA/DVS before SBF immersion (day 0) was 0.83 (Figure b), so the initial scaffold was a calcium-deficient apatite-like biocomposite, because in stoichiometric HA, the Ca/P ratio is 1.67 . However, we found the deposition of apatite-like particles (and particle aggregates) on the HPG- g -PNVCL/n-HA/DVS scaffold surface after immersion in SBF for 7 and 14 days.…”

“…These deposits were caused by the initiation of apatite nuclei on the scaffold surface, which produced crystals by absorbing more calcium (Ca 2+ ) and phosphorous (PO 4 3– ) from the SBF, thus displaying bioactivity. After a 7 day period, the Ca/P ratio increased from 0.83 to 2.00similar to the Ca/P ratio in stoichiometric HA (1.67) and the theoretical Ca/P ratio in human bone (1.75) . After 14 days, formation of apatite on the surface was slightly greater.…”

“…After a 7 day period, the Ca/P ratio increased from 0.83 to 2.00—similar to the Ca/P ratio in stoichiometric HA (1.67) and the theoretical Ca/P ratio in human bone (1.75). 60 After 14 days, formation of apatite on the surface was slightly greater. These results confirm that calcium-rich apatite was deposited on the scaffold’s surface forming a bone-like structure and composition.…”

Crosslinked chitosan‐based biocomposite films modified with soy protein isolate

“…Under ever‐increasing pressure to ensure environmentally friendly materials, there is a growing interest in developing active packaging with film‐forming capacity and antimicrobial properties to improve food safety and shelf life . Chitosan film is of particular interest due to its moderate water permeability, superior antifungal properties, and ability to form an oxygen barrier .…”