Table 1.
The preparation methods of magnetic hydrogels and the parameters of magnetic field in representative references.
| Method | Magnetic particles | Hydrogels | Magnetic particle concentration | Physiochemical properties | Magnetic field | References |
|---|---|---|---|---|---|---|
| Blending method | Fe3O4 | Bisphosphonate-modified HA | 2 w/v% | Proper rheology and fast heat-generation | Alternating magnetic field | Shi et al., 2019 |
| Fe3O4 | Chitosan/PEG | 0–40 wt% | Nanoheat | Alternating magnetic field | Cao et al., 2018 | |
| Fe3O4 | NIPAAM-MAA | 2.5 mg/mL | Uniform distribution of particles | – | Namdari and Eatemadi, 2017 | |
| Fe2O3 | Poly(vinyl alcohol)/n-HAP | 4 wt% | High water content and good elasticity | – | Huang J. et al., 2018 | |
| Magnetite | Hyaluronate hydrogel | 0.2, 2.0 g/L | Stable and homogeneous dispersion in 3 months | – | Tóth et al., 2015 | |
| Magnetite | Collagen | 0.5 mg/mL | Aligned collagen fibers and normal electrical activity | Magnet (255 G) | Antman-Passig and Shefi, 2016 | |
| Dextran iron oxide composite particles (Micromod®) | Agarose | 20 wt% (surface) 7 wt% (middle) 10 wt% (deep) |
Gradients in compressive modulus | Rare earth NdFeB magnets (0.4, 0.5, or 0.75 T; E-Magnets®) | Brady et al., 2017 | |
| Streptavidin-coated magnetic particles | Agarose/collagen | 10 v/v% | Mimicking the native multilayered tissues | Magnet (2 mT) | Betsch et al., 2018 | |
| Nano-HAP-coated γ-Fe2O3 nanoparticles (m-nHAP) | Poly(vinyl alcohol) | 0–80 wt% | Linearly saturated magnetic strength and porous structures, homogenous dispersion of m-nHAP and improved compressive strength | – | Hou et al., 2013 | |
| PEG-functionalized iron oxide (II, III) nanoparticles | PEG hydrogel (modified with factor XIIIa) | 1 mg/mL | Smooth inner gel texture, slow relaxation kinetics, and high elastic modulus | Neodymium magnets (50 mT) | Filippi et al., 2019 | |
| MNPs | Collagen | – | Bio-mimetic 3D structures | Static magnetic fields | Yuan et al., 2018 | |
| MNPs | Poly(lactide-co-glycolide) | 1, 5, and 10 wt% | Homogenous distribution of MNPs and linear structures | Standard cuvette Magnets (100–300 mT) |
Omidinia-Anarkoli et al., 2017 | |
| MNPs | Six-arm star-PEG-acrylate | 0.0046 vol% | Unidirectional structures and high controlled properties | Magnets (100, 130, and 300 mT) | Rose et al., 2017 | |
| MNPs | RGD peptides modified alginate | 7 wt% | Fatigue resistance | Magnet (6,510 G, 1 Hz) | Cezar et al., 2016 | |
| MNPs | GRGDSPC peptides/six-arm PEG-acrylate | 400 μg/mL | Tailed properties | Magnet (150 mT) | Rose et al., 2018 | |
| In situ precipitation method | Fe3O4 | Chitosan | 0–15 wt% | Uniform distribution of MNPs and enhanced mechanical properties | Low frequency magnetic field (60 Hz) | Wang et al., 2018 |
| Polydopamine-chelated carbon nanotube-Fe3O4 | Acrylamide | 0–15 wt% | Directional conductive and mechanical properties | Low static magnetic field (30 mT) | Liu et al., 2019 | |
| Dextran-coated Fe3O4 | Bacterial cellulose | 25–100 mM | Magnetization saturation (10 emu/g) and moderate Young's modulus (200–380 KPa) | Neodymium magnets (0.3 T) | Arias et al., 2018 | |
| Grafting-onto method | CoFe2O4 | Polyacrylamide | – | High stability and homogeneity | – | Messing et al., 2011 |
| Poly(vinyl alcohol) modified Fe3O4 | Hybrid hydrogel (containing HA, collagen, and PEG) | 4 wt% | Increased surface roughness and biodegradation | Magnet | Zhang et al., 2015 | |
| 3-(trimethoxysilyl)propyl methacrylate coated Fe3O4 | Polyacrylamide | 20–60% (with respect to the total weight of the hydrogels and water) | High mechanical properties and excellent underwater performance (polydimethylsiloxane coating) | – | Hu et al., 2019 | |
| Carboxyl-coated Nanomag® superparamagnetic nanoparticles (Micromod®) | RGD-tripeptide; TREK1-antibody | – | – | Mica Biosystem bioreactor | Henstock et al., 2014 | |
| Saline modified carbonyl iron particles | Polyacrylamide | – | Elastic hysteresis | Alternating magnetic field | Abdeen et al., 2016 | |
| Glycosylated MNPs | Agarose | 1011 glycosylated MNPs in 100 μL 1 wt% agarose hydrogel | MNPs-gradient magnetic hydrogel | Finite element magnetic modeling | Li et al., 2018 | |
| Methacrylated chondroitin sulfate (MA-CS)-MNPs | MA-CS enriched with platelet lysate | 200 and 400 μg/mL | Homogenous trabecular structures and high storage modulus | Oscillating magnet array system | Silva et al., 2018 | |
| Kartogenin (KGN) grafted ultrasmall superparamagnetic iron oxide | Cellulose nanocrystal/dextran hydrogel | 0.06–0.3 wt% | Good mechanical strength, long-term sustained KGN release, and stable MRI capabilities | – | Yang et al., 2019 | |
| PEG-magnetic microparticles | Thiolated HA | – | Uniform distribution of MMPs and mimicking the native tissue ECM | Applied magnetic field (2 T) | Tay et al., 2018 |