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| Method | Polymers | Unique factors | Application |
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| Biodegradable porous scaffold fabrication | | | |
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| Solvent casting/salt leaching method [35–37] | Absorbable polymer (PLLA, PLGA, collagen, etc.) | Biodegradable controlled porous scaffolds | Bone and cartilage tissue engineering |
| Ice particle leaching method [38–40] | PLLA & PLGA | Control of pore structure and production of thicker scaffolds | Porous 3D scaffolds for bone tissue engineering |
| Gas foaming/salt leaching method [41–43] | PLLA, PLGA & PDLLA | Controlled porosity and pore structure sponge | Drug delivery and tissue engineering |
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| Microsphere fabrication | | | |
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| Solvent evaporation technique [44–46] | PLGA, PLAGA | High-density cell culture, due to the extended surface area | Bone repair |
| Particle aggregated scaffold [47–49] | Chitosan, HAP | High mechanical stability | Bone, cartilage, or osteochondral tissue engineering |
| Freeze drying method [50–52] | PLGA, PLLA, PGA, PLGA/PPF, Collagen, and Chitosan | 3D porous sponge structure, durable and flexible | Tissue engineering scaffolds |
| Thermally induced phase separation [53, 54] | PEG, PLLA | Highly porous scaffold for cellular transplantation | Complicated shapes for tissue engineering applications |
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| Injectable gel scaffold fabrication | | | |
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| Ceramic-based injectable scaffolds [55–57] | CP ceramics, HAp, TCP, BCP, and BG | Porosity and bioresorbability | Cartilage tissue engineering |
| Hydrogel-basedinjectable scaffolds [58–60] | Hydrophilic/hydrophobic diblock and triblock copolymer combinations of PLA, PGA, PLGA, and PEG. Copolymers of PEO and PPO and polyoxamer. Alginates, collagen, chitosan, HA, and fibroin | Biomimetically, exhibit biocompatibility and cause minimal inflammatory responses, thrombosis, and tissue damage | Cartilage, bone tissue engineering, and drug delivery |
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| Hydrogel scaffold fabrication | | | |
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| Micromolding [61–63] | Alginate, PMMA, HA, PEG | Microgels, biologically degradable, mechanical and physical Complexity | Insulin delivery, gene therapy, bioreactor, and immunoisolation |
| Photolithography [64–66] | Chitosan, fibronectin, HA, PEG, PNIAAm, PAA, PMMA, PAam, and PDMAEM | Microwells, microarrays, controlled size and shape | Microdevices, biosensors, growth factors, matrix components, forces, and cell-cell interactions |
| Microfluidics [67–69] | PGS, PEG, calcium alginate, silicon and PDMS | Microbeads, microrods, valves, and pumps | Sensing, cell separation, cell-based microreactors, and controlled microreactors, |
| Emulsification [70–72] | Gelatin, HA, and collagen | Microgels, microsensors, cell-based diagnostics | Sustainable and controllable drug delivery therapies |
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| Acellular scaffold fabrication | | | |
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| Decellularisation process [73–75] | Biological tissues | Retain anatomical structure, native ECM, and similar biomechanical properties | Tissue engineering |
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| Keratin scaffold fabrication | | | |
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| Self-assembled process [76–78] | Keratin | Biocompatibility | Drug delivery, wound healing, soft tissue augmentation, synthetic skin, coatings for implants, and scaffolds for tissue engineering |
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| Fibrous scaffold fabrication | | | |
|
| Nanofiber electrospinning process [79–81] | PGA, PLA, PLGA, PCL copolymers, collagen, elastin, and so forth | High surface area, biomechanical, and biocompatibility | Drug delivery, wound healing, soft tissue synthetic skin, and scaffolds for tissue engineering |
| Microfiber wet-spinning process [82–84] | PLGA, PLA, chitosan, and PCL | Biocompatible fibres with good mechanical properties | Solar sails, reinforcement, vascular grafts, nonwetting textile surfaces, and scaffolds for tissue |
| Nonwoven fibre by melt-blown process [85–87] | Polyesters, PGA, and PDO | Submicron fiber size, highly porous scaffold | Filtration, membrane separation, protective military clothing, biosensors, wound dressings, and scaffolds for tissue engineering |
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| Functional scaffold fabrication | | | |
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| Growth factor’s release process [88–90] | Collagen, gelatin, alginate, chitosan, fibrin, PLGA, PLA, and PEG | Membranes, hydrogels, foams, microsphere, and particles | Angiogenesis, bone regeneration, and wound healing |
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| Ceramic scaffold fabrication | | | |
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| Sponge replication method [91–93] | PU sponge, PVA, TCP, BCP or calcium sulfate | Interconnected porous ceramic scaffolds | Bone tissue engineering |
| Simple calcium phosphate coating method [94–96] | Coating on: metals, glasses, inorganic ceramics and organic polymers (PLGA, PS, PP, silicone, and PTFE), collagens, fibres of silk, and hairs | Improve biocompatibility or enhance the bioreactivity | Orthopedic application |
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| Automation and direct organ fabrication | | | |
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| Inkjet printing process [97–100] | Sodium alginate | To build complex tissues composed of multiple cell types (Hydrogel scaffold) | Biosensor development, microdeposition of active proteins on cellulose, biochips and acellular polymeric scaffolds |
| Melt-based rapid prototyping process [101, 102] | Biodegradeable polymers or blends | Complex 3D solid object, good mechanical strength | Honey comb structure scaffold, hard-tissue scaffolds |
| Computer-aided design (CAD) data manipulation techniques [103–105] | | Design and fabrication of patient-specific scaffolds and automated scaffold assembly algorithm | Develop a program algorithm that can be used to design scaffold internal architectures |
| Organ printing [106, 107] | Tubular collagen gel | Layer by layer deposition of cells or matrix | To print complex 3D organs with computer-controlled, |
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| Scaffold sterilization | | | |
|
| Ethylene oxide gas (EOG) [108–110] | | For degradable polymers and porous scaffolds, high penetration ability, and compatibility | Absolute freedom from biological contamination in scaffolds |
| Gamma-radiation sterilization [111–113] | | Proven process is safe, reliable, and highly effective at treating single-use medical devices | Surgical disposables: surgical sutures, bandages, dressings, gauge pads, implants |
| Electron beam radiation [114–116] | | Compatibility, low penetration, in line sterilization of thin products | Commercially successful technology for sterilizing a variety of disposable medical devices with a wide range of densities |
| Dry-heat sterilization [117, 118] | | Efficacy, speed, process simplicity, and lack of toxic residues | Heat is absorbed by the exterior surface of scaffold and then passed inward to the next layer |
| Steam sterilization [119, 120] | | Removal of all contamination, and scaffold can be reused | Porous scaffold for living cell immobilization |
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