## 2 Results and Discussion
### Scaffold Fabrication
The FGSr composite showed the higher denaturation temperature at 108.8 \({}^{\circ}\)C. The improved thermal stability is due to the interaction of ceramic and FG during photocuring process of the scaffold. The FTIR spectrum of FG and FGSr specimens containing characteristic peaks resembled both spectrum of FG and calcium silicate (Figure 2C). FG show the peaks at approximately 1635 cm\({}^{-1}\) (amide-I, C = O stretching), 1535 cm\({}^{-1}\) (amide-II, N-H bending) and 1242 cm\({}^{-1}\) (amide-III, C-N and N-H stretching) [34]. The band at 1130 to 1260 cm\({}^{-1}\) is attributed to the asymmetric stretching vibration of SiO4, while siloxane (Si-O-Si) stretching at 919 to 1024 cm\({}^{-1}\)[35]. As seen in Figure 2D, FGSr had multiple peaks at 29.7\({}^{\circ}\) (C3S), 33.3\({}^{\circ}\) (Sr2 SiO4), 35\({}^{\circ}\) (Ca(OH)2) and 32.8\({}^{\circ}\), 35.2\({}^{\circ}\) and 40\({}^{\circ}\) (SrSiO3) which strongly indicates that SrCS was present in the hydrogel scaffold. Furthermore, this result also implied that the addition of SrCS did not adversely affect the original structural properties of FG, thus suggesting that several beneficial properties of FG that were desired were retained in the FGSr scaffolds [15]. The Dynamic mechanical analysis (DMA) is conducted to consider the reinforcing effect brought by the addition of Sr ceramic in FG gel. The temperature dependent of the storage modulus, loss modulus, and tan \(\delta\) for different scaffolds were show in Figure 3. The storage modulus of FGSr indicated  
Figure 2: **(A)** TGA, **(B)** DSC, **(C)** FTIR and **(D)** XRD for specimens prepared with a series of FG and FGSr scaffolds. the significant improvement compared to that of FG that demonstrates the elastic behavior of FGSr scaffold towards deformation is superior to that of FG scaffold. In addition, for the curves of tan \(\delta\) for versus temperature, the glass transition temperature (Tg) of FGSr scaffold was obviously shifted to the higher temperature because of the Sr ceramic powder increased the crosslink density that restricted the motion of FG molecular chains [36]. Representative stress-strain curves of both FG and FGSr scaffolds were shown in Figure 4. As seen, it was clearly indicated that FGSr had significantly higher mechanical properties as compared to neat FG scaffolds with approximately 9.2 kPa for FGSr and 3.8 kPa for FG. There was almost a 2.5-fold increase for the FGSr scaffold which makes it a better candidate for further clinical applications. A major disadvantage of FG is that it has lower mechanical strength as compared to its porcine or bovine counterparts due to FG having different amino acid composition and molecular weight distribution. In addition to the photo-crosslinking curing mechanism of FGSr, we speculate that SrCS will release ions to allow FGSr hydrogel to crosslink and provide more chances for the reaction at the beginning, which can also improve the stability of the hydrogel scaffold after photocuring. Similar studies were demonstrated that high-mechanical properties polymer-based hydrogels were manufactured using a sequential physical combined chemical crosslinking process [37; 38]. Therefore, the addition of SrCS powder can improve the mechanical properties of the scaffold thus its clinical availability will be relatively improved in the future. SEM was used to observe for the morphology and microstructures of the scaffolds before and after immersion and the images were shown in Figure 5. As seen from the W0 images, FG had fine sharp folds and creases on its surface whilst FGSr had rough and irregular contours on its surface. Initial hypothesis suggested that FGSr would be able to enhance regeneration as it was reported by others that the degree of surface roughness is directly correlated to cellular activities and behaviors [39]. After 4 weeks of immersion, it could be seen from the SEM images that FG had a smooth surface whilst FGSr had coarse apatite aggregations covered on its entire surface.