Table 3.
Overview of publications on the self-supporting hydrogel bioprinting of (osteo) chondral and zonally organized cartilage regenerative constructs.
| Material(s) | Cell Type(s) | Mechanical Properties | Crosslinking Mechanism(s) | Outcomes | Reference |
|---|---|---|---|---|---|
| Hydrogel Bioprinting of Chondral Constructs | |||||
| Alginate | ATDC5 chondrogenic cell line and embryonic chick chondrocytes | Unconfined compressive modulus: 20~70 kPa (depending on the culture time and crosslinking densities) | Ionic | ~85% cell viability, show cartilage extracellular matrix formation in constructs | [128] |
| Nanocellulose with alginate | Human nasoseptal chondrocytes | Unconfined compressive modulus: 75~250 kPa (depending on the ratio of two materials) | Ionic | 73–86% cell viability | [34] |
| Methacrylated chondroitin sulfate (CSMA) with a triblock copolymer poly (N-(2-hydroxypropyl)methacrylamide-mono/dilactate) | ATDC5 chondrogenic cell line | Unconfined compressive modulus: 7–60 kPa (depending on the degree of methacrylation) | Photo | ~95% cell viability | [158] |
| GelMA with gellan gum | ATDC5 chondrogenic cell line | Unconfined compressive modulus: 18–59 kPa (depending on the concentration of gellan gum) | Ionic, photo and thermal | Approximately 50% cell viability in plotted gels due to the supraphysiological temperature of 40–50 °C. | [94,159] |
| GelMA with gellan gum | Equine articular chondrocytes | Unconfined compressive modulus: 2.7–186 kPa (depending on ratio and content of two components) | Ionic, photo and thermal | Support cartilage matrix production, higher gellan gum contents improves the printability but compromise cartilage ECM, and high total polymer concentrations hamper the distribution of ECM. | [94,159] |
| Fibroin and gelatin | Human mesenchymal stem cells, Human articular chondrocytes | Not reported | Enzymatic | 84–90% cell viability of both cell types during 14 days of culture, supported cartilage ECM deposition and remodeling, minimize hypertrophic differentiation towards development and promote cartilage development. | [73] |
| Hydroxyethyl methacrylate derivatized dextran (Dex-HEMA) and hyaluronic acid (HA) | Equine articular chondrocytes | Ultimate compressive stress: 100–160 kPa (depending on the HA content), uncontained compressive modulus: 26 kPa for different constructs | Photo | Cell viabilities are 94% and 75% after day 1 and day 3 | [153] |
| Diacrylated Pluronic F127 and methacrylated HA | Bovine articular chondrocytes | Unconfined compressive modulus: 1.5–6.5 kPa (depending on the methacrylated HA content) | Photo | Cell viability is between 60% to 85%. | [152] |
| GelMA constructs reinforced with methacrylated pHMGCL/PCL | Human articular chondrocytes | Unconfined compressive failure force ~2.7 N and ~7.7 N when covalent bonds between gelMA and methacrylated pHMGCL/PCL are established | Photo | Cartilage ECM network consisting of GAGs and Collagen type II are formed after 6 weeks of in vitro culture and Collagen type II production was more pronounced in vivo compared to in vitro | [29] |
| Gellan, alginate and cartilage extracellular matrix particles | Bovine articular chondrocytes | Tensile modulus ~116–230 kPa | Ionic and thermal | Cell viability: 80% and 96%, 60% viable cells are observed in the centre of some samples at day 7. Constructs with cartilage ECM particles increased cartilage ECM formation, but the influence of TGF-β3 on cartilage ECM is more pronounced and constructs with TGF-β3 showed most cartilage ECM formation | [27] |
| Methacrylated HA with HA-pNIPAAM | Bovine articular chondrocytes | Not reported | Thermal and photo | Cell viability is negatively influenced by the addition of HA-pNIPAAM | [28] |
| Hydrogel Bioprinting of Osteochondral Constructs | |||||
| Alginate (cartilage) Gelatin with demineralized bone matrix (bone) |
Cell-free | Not reported | Ionic | Directly printing into an osteochondral defect of a bovine femur and showed good geometric fidelity | [156] |
| Alginate (cartilage) Alginate with biphasic calcium phosphate particles (bone) |
Human articular chondrocytes (cartilage) Human mesenchymal stromal cells (bone) |
Unconfined compressive modulus: 4.5–15 kPa (depending on porosity of constructs) | Ionic | Cell viability: ~89% Cartilage and bone ECM formed in designed regions of the constructs after culturing for 3 weeks. In vivo tests showed similar results after 6 weeks of culture |
[157] |
| GelMA with gellan gum (cartilage) GelMA, gellan gum and polylactic acid microcarriers (bone) |
Murine mesenchymal stromal cells | Unconfined compressive modulus: ~25–50 kPa (depending on concentration of microcarriers) | Photo and ionic | Cell viability: 60–90% | [93] |
| Hydrogel Bioprinting of Zonally Organized Cartilage Constructs | |||||
| Collagen type II | Rabbit articular chondrocytes (2 × 107 cells/mL in superficial zone, 1 × 107 cell/mL in middle zone and 0.5 × 107 cells/mL in deep zone) | Not reported | Thermal | Cell viability: 93% Zonally organized cartilage constructs could be fabricated by bioprinting Collagen type II hydrogel constructs with a biomimetic cell density gradient. The cell density gradient distribution resulted in a gradient distribution of ECM | [49] |