TABLE 2.
Summary of various biomaterials for AF repair and their functions.
| Material type | Material composition | Target cell/gene | In vivo experimental model | Repair effect | References | |
|---|---|---|---|---|---|---|
| Surgical suture | Anulex Technologies, Minnetonka, MN | NA | Patients with lumbar disc herniation | Reduce the need for subsequent reherniation surgery while retaining the benefits of discectomy with no increased risk for patients | Bailey et al. (2013) | |
| an anular closure device | NA | Patients with lumbar disc herniation | Provide very low rates of disk reherniation and exhibit excellent disk height maintenance and sustain disability, leg pain, and back pain improvement within a 24 months postoperative study period | Vukas et al. (2015) | ||
| Hydrogel | g-DAF-G | Human BMSCs | Rat tail acupuncture degenerative model | Exhibit well biocompatibility, great bioactivity, and much higher mechanical strength | Peng et al. (2020a) | |
| Genipin cross-linked fibrin gel (FibGen) adding PDLGA | NA | NA | FibGen is highly modifiable with tunable mechanical properties that can be formulated to be compatible with human AF compressive and shear properties and gelation kinetics and injection techniques compatible with clinical discectomy procedures | Cruz et al. (2017) | ||
| HDC cross-linked with riboflavin | AF cell | Needle puncture-induced degeneration rat model | AF cell-laden HDC gels have the ability of better repairing annular defects than acellular gels after needle puncture | Moriguchi et al. (2018) | ||
| ILM-GAG | NA | NA | Adding ILM glycosaminoglycan (GAG) can enable the annulus repair patch (AFRP) to withstand stronger impact strength and prevent the nucleus pulposus from herniating again when over physiological load | Borem et al. (2019) | ||
| AF decellularized tissue matrix | Human BMSCs | AF defect rat model | AF specific differentiation of stem cells and AF tissue regeneration | Peng et al. (2021) | ||
| Anisotropic wood cellulose hydrogel | Mouse BMSCs | NA | Possesses imitation and construction of the natural structure, favorable mechanical matching and good biocompatibility and unique mechanical buckling buffer characteristics | Liu et al. (2021) | ||
| Double-modified glycosaminoglycan | NA | Ex vivo bovine model of discectomy | Covalently bond hydrogels to AF tissue to seal AF defect | DiStefano et al. (2020) | ||
| Nanofiber | PLGA/PCL DEX | AF cells | in vitro inflammation model induced by interleukin (IL)-1β | The nanofiber membrane composed of P10P8D2 and PTE has anti-inflammatory and pro-proliferation effects on AF cells | Wang et al. (2021) | |
| PECUU | AF-derived stem cells | NA | YAP-related proteins play a key role in influencing the differentiation direction of AFSC. The scaffold can effectively induce changes in cell shape, adhesion and expression of ECM by adjusting the fiber size, so that the engineered AF tissue has a layered structure close to that of natural AF tissue | Chu et al. (2019) | ||
| DAFM/PECUU-blended electrospun scaffolds | AF-derived stem cells | NA | Gene expression and ECM secretion of collagen type I and II and aggrecan from AF-derived stem cells cultured on DAFM/PECUU electrospun scaffolds were higher than from those on PECUU fibrous scaffolds | Liu et al. (2020) | ||
| PCL | Bovine AF cell | NA | Bovine AF cells can be attached and diffused on it, and type I collagen, aggrecan, and AF specific protein markers can be effectively expressed | Christiani et al. (2019) | ||
| PCL and PLLA | Bovine AF cell | NA | For the first time, a custom-built Cell Sheet Rolling System (CSRS) was utilized to create a 3D circular lamellae construct that mimics the complex AF tissue and which overcomes this translational limitation | Shamsah et al., 2019 | ||
| Cell therapy | Silk protein-based multilayered, disc-like angle-ply construct | Porcine AF cells and hMSCs | NA | The constructs supported cell proliferation, differentiation, and ECM deposition resulting in AF-like tissue features based on ECM deposition and morphology | Bhunia et al. (2018) | |
| PTMC and TGF-β3 | HASCs | NA | Production of sGAG and collagen was significantly upregulated, but the formed collagen was also oriented and aligned into bundles within the designed pore channels. The differentiated hASCs seeded with fibrin gel were also found to have a comparable sGAG:collagen ratio and gene expression profile as native AF cells | Blanquer et al. (2017) | ||
| PTMC and PU | Human BMSCs | AF rupture repair in a bovine organ culture annulotomy model | It can withstand dynamic loads, restore the height of the intervertebral disc, prevent the protrusion of the nucleus pulposus, and has the ability to differentiate in situ | Pirvu et al. (2015) | ||