Biohybrid methacrylated gelatin/polyacrylamide hydrogels for cartilage repair

Abstract

Articular cartilage defect repair is challenging for clinics because it is avascular tissue lack of self-regenerative ability. Gelatin-based hydrogels are widely used in the field of tissue engineering because of their good biodegradability, excellent biocompatibility, and cell/tissue affinity. However, gelatin-based hydrogels exhibit poor thermal stability and low mechanical strength, which limits their applications in cartilage repair. In this study, methacrylic anhydride (MA) was employed to modify gelatin to obtain photo-crosslinkable methacrylated gelatin (GelMA). The GelMA-based natural-synthetic polymer biohybrid hydrogel was prepared by co-polymerizing acrylamide (AM) and GelMA under ultraviolet radiation in the presence of a photo-initiator. The GelMA/PAM biohybrid hydrogel simultaneously possessed the advantages of both PAM hydrogels and GelMA hydrogels. The GelMA block provided specific biological functions for cell adhesion and proliferation, while the flexible PAM chains reinforced the brittle gelatin network and sustain load during deformation. Compared with pure PAM hydrogel and GelMA, the GelMA/PAM biohybrid hydrogels showed enhanced compression strength (0.38 MPa) and improved elasticity (storage modulus of 1000 Pa). The GelMA/PAM biohybrid hydrogel showed a favorable degradation rate and sustained protein release. In vitro cell culture showed that the chondrocytes remained viable and proliferated on the biohybrid hydrogel, demonstrating that the biohybrid hydrogels had good cell adhesion and excellent biocompatibility. In a rabbit knee cartilage defect model, we evaluated the cartilage repair ability of the biohybrid hydrogel in vivo. In summary, this study demonstrated that hybridization of synthetic polymers considerably improves the performance and expands the application of the gelatin-based hydrogels. The biohybrid

Multifunctional Nanoengineered Hydrogels Consisting of Black Phosphorus Nanosheets Upregulate Bone Formation

“…In addition, the swelling ratio of the DN and NE hydrogels is much smaller than that of PAM hydrogel, as evaluated by soaking the hydrogels in phosphate buffered saline (PBS) (Figure S14a, Supporting Information). Swelling assays showed that the volume of DN and NE hydrogels increased during the initial 3 h and reached equilibrium after 5 h of immersion, while the PAM hydrogel required 15 h to reach equilibrium, which is consistent with our previous study . It should be noted that the addition of BP nanosheets into DN hydrogels slightly decreased the swelling ratio of NE hydrogels, and the NE PAM/AlgMA/BP hydrogels showed the lowest swelling ratio throughout the testing period.…”

Development of a Photo-Crosslinking, Biodegradable GelMA/PEGDA Hydrogel for Guided Bone Regeneration Materials

“…Then, the hydrogel was lyophilized to obtain dry weight W d . The swelling degree was calculated as following equation [27]: $\mathrm{Swelling}\mathrm{ratio}=\frac{Ws-Wd}{Ws}$…”

“…The collagenase solutions were replaced by fresh ones every 2 days to maintain constant enzyme activity. At different times, the sample was removed from collagenase solution and washed twice with sterile deionized water, lyophilized, and weighted [27]. The degradation rate was calculated using equation:$\mathrm{Degradation}\mathrm{Rate}(\%)=\frac{w_0-w_t}{w_0}\times 100\%$…”

Osteochondral Regeneration with 3D‐Printed Biodegradable High‐Strength Supramolecular Polymer Reinforced‐Gelatin Hydrogel Scaffolds

“…While at a constant ACG content, the mechanical strengths exhibit first an increasing trend and then decrease with increasing GelMA content. [34] It is noteworthy that the complete degradation times of PACG10-GelMA10 and PACG35-GelMA7 hydrogel are 35 and 63 days, respectively. In the selected range of initial concentrations of ACG, the PACGX-GelMA4 hydrogels achieve 0.018-0.721 MPa tensile strength, 42-224% break strain, 38-252 kPa Young's modulus, 0.048-8.9 MPa compressive strength, 7-471 kPa compressive modulus, and 68-93% compressive failure strain.…”