Table 2. Synthetic Bone–Tendon Scaffolds Manufactured Using Various Techniques and Biomaterialsa.
| Study | Material bone | Material tendon | Scaffold Type | Processing method | Mechanical properties (tensile) | Biological aspect |
|---|---|---|---|---|---|---|
| (199) | PLGA-nanofibers with HA | PLGA-nanofibers | Monolithic (two types) | Electrospinning | ||
| (209) | Random PLGA-nanofibers | Aligned PLGA-nanofibers | Monolithic (two types) | Electrospinning and rotating mandrel electrospinning | Random scaffold | The organization and arrangement of nanofibers significantly affect the human rotator cuff fibroblast responses including cell attachment and matrix deposition. This controlled cell response exhibited potentials for tendon regeneration. |
| EM: 107 MPa | ||||||
| YS: 2.5 MPa | ||||||
| UTS: 3.7 MPa | ||||||
| Aligned scaffold | ||||||
| EM: 341 MPa | ||||||
| YS: 9.8 MPa | ||||||
| UTS: 12 MPa | ||||||
| (210) | Random PLGA-nanofibers | Aligned PLGA-nanofibers | Bilayered | Electrospinning | Aligned EM: 143 ± 98 MPa | Culturing tendon cells on scaffolds with aligned and random nanofiber orientation showed respectively random and aligned cell orientation. |
| Random EM: 53 ± 24 MPa | ||||||
| (32) | PCL-microfibers with PLGA-microspheres | PCL-microfibers with PLGA-microspheres | Multilayered (3 layers) | AM | Stiffness: 15 N/mm | The engineered multiphase fibrocartilaginous interface scaffold was tested in vitro using mesenchymal progenitor cells and in vivo as it was implanted at the bone–tendon interface in a rat rotator cuff repair model. The scaffolds successfully promoted the regional differentiation, consequently leading to enhanced healing of bone–tendon interfaces. |
| Max load: 20 N | ||||||
| (214) | Collagen-GAG and CaP | Collagen-GAG interface zone: PEG-hydrogel | Multilayered (3 layers) | Freeze-drying (+ diffusion and gelation) | Storage modulus G′eq: between 4 and 16 kPa | |
| (201) | Collagen and HA | 1. Collagen | Multilayered (4 layers) | Freeze-drying | EM (1,2,3,4): 0.3/1.2/3.0/4.5 MPa | The in vitro results of the multilayer scaffold supported the adhesion and proliferation of human fibroblasts, chondrocytes, and osteoblasts. |
| 2. Cross-linked aggrecan-collagen (chondroitin sulfate) | Elongation at breakpoint: 113%/106%/82%/71% | |||||
| 3. Partly calcified collagen | ||||||
| (196) | PLGA-nanofibers with CaP | PLGA-nanofibers | Gradient | Electrospinning and plasma treatment | The level of mineral content on the surface of the nanofibers can control the osteogenesis of ASCs for enthesis repair. | |
| (200) | PLGA-nanofibers with HA | PLGA-nanofibers | Gradient | Electrospinning | EM: 3.1 GPa | |
| (13) | PLGA/PCL-Gelatin-nanofibers with CaP | PLGA/PCL-Gelatin-nanofibers | Gradient | Electrospinning | EM: 40–120 MPa | Introducing gradient in the calcium phosphate content has influenced the activity of mouse preosteoblast MC3T3 cells. |
| (211) | Random PCL-nanofibers | Aligned PCL-nanofibers | Gradient | Electrospinning | The scaffolds were seeded by ASCs which exhibited different morphologies at different locations. These results were because of the capability of the fabrication technique in encapsulation of desired materials inside deposited nanofibers. | |
| (197) | Random PCL-nanofibers | Aligned PCL-nanofibers | Gradient | Electrospinning | The random-to-aligned interface scaffolds were cocultured by osteosarcoma and fibroblast cells which resulted in a random-to-aligned cocultured tissue interface after 96 h culturing mimicking the microarchitecture of enthesis. | |
| (31) | PCL-Gelatin-microfibers with HA | PCL-Gelatin-microfibers | Gradient | Wet-spinning and knitting | PCL/gelatin | The results of biological performance using human ASCs showed that topography of PCL/gelatin microfibers can induce cellular anisotropic alignment (i.e., cytoskeleton elongation), resembling native tenogenic organization. |
| EM: 252 MPa | ||||||
| YS: 4.7 MPa | ||||||
| Strain to failure: 295% | ||||||
| PCL/gelatin/HA | ||||||
| EM: 59 MPa | ||||||
| YS: 1.0 MPa | ||||||
| Strain to failure: 442% | ||||||
| (66) | PUR-QHM-polymers (UV-exposed) | PUR-QHM-polymers | Gradient | Photocross-linking, and heat-curing | Tensile tests | Biophysiochemical results showed favorable characteristics for bone–tendon repair. |
| EM: 0.6–2.7 GPa | ||||||
| YS: 12–74 MPa | ||||||
| Compressive tests | ||||||
| EM: 1.5– 3.0 GPa | ||||||
| YS: 58–121 MPa |
a
The acronyms summarized in this table are PLGA = poly(lactide-co-glycolide) acid, HA = hydroxyapatite, PCL = polycaprolactone, EM = elastic modulus, YS = yield strength, UTS = ultimate tensile strength, GAG = glycosaminoglycan, CaP = calcium phosphate, PUR = polyurethane, QHM = Quadrol hexamethylene diisocyante, UV = ultraviolet, adipose-derived mesenchymal stem cells = ASCs.