3.2. Characterizations of scaffolds after in vitro assays
The XRD patterns of 1CH-1BG, 1CH-2BG, and 2CH-1BG scaffoldsafter 30 days of immersion in the SBF are presented in Fig. 6. Sev-eral references as 46S6, chitosan scaffolds before immersion werechosen to observe an eventual change in the structure [27–32].The hydroxyapatite was chosen as reference to present its even-tual formation on materials. A halo of diffraction is observed for2CH-1BG scaffolds between 15 and 25 (2◦) due to the high amount
Table 4
Major vibration bands associated with chitosan and bioactive glass.
Material Wave number (cm−1) Group assignment References
Chitosan 1900–1500 Amide I: C O [31]
Chitosan 1650–1550, 1570–1515 N H(I), N H(II) [31]
Chitosan 1154–896 COC (saccharide--1-4) [31]
Chitosan 1300–1000 C O (cyclic) [31]
BG 1350–1080 P O Stretch [32]
BG 940–860 Si O Si Stretch [32]
BG 890–800 C O Stretch [32]
BG 1175–710 Si O Si Tetrahedral [32]
BG 560–550 P O Bend [32]
BG 540–415 Si O Si Bend [32]
of chitosan. After 30 days of immersion in the SBF, the formationof hydroxyapatite is confirmed by the appearance of two peaksof diffraction: at 25.9 (2◦) corresponding to the (0 0 2) apatitereflection and 31.8 (2◦) corresponding to the (2 1 1) apatite reflec-tion [33]. For all the scaffolds, the bioactivity is observed from15 days of immersion. Therefore, the content of 46S6 does nothave a significant effect on the bioactivity of scaffolds. Indeed,the hydroxyapatite appears for each scaffold. The bioactive glassreleases calcium, phosphorus and silicon ions in the SBF and allowsthe formation of hydroxyapatite. The ionic exchanges study wasperformed by using ICP-OES. However, a better crystallization ofhydroxyapatite is observed for 2CH-1BG. This phenomenon may berelated to the specific surface area of the samples. Having a largerspecific surface area and a larger pore volume, 2CH-1BG scaffoldspromotes the flow of the SBF through the material, favoring ionexchanges and forming a better crystallized hydroxyapatite.