Table 3.
Hybrid hydrogels.
| Hybrid Hydrogels | |||||||
|---|---|---|---|---|---|---|---|
| Author | Hydrogel Used | Type of Study | Hydrogel Modification | Hydrogel Properties |
Cells Used | Upregulated Biological Molecules | Outcomes |
| Alginate/laponite hydrogel | |||||||
| Zhang et al., 2020 [56] | Alginate/laponite hydrogel | In vitro In vivo |
Arginine-glycine-aspartic acid (RGD) modified alginate and nano-silicate laponite hydrogel microspheres, encapsulating human dental pulp stem cells (DPSCs) and vascular endothelial growth factor (VEGF). |
The RGD-Alg had 55% degradation rate and the RGD- alginate/laponite exhibited 45% while pure alginate degraded only 20% after 28 days. | DPSCs | Alkaline phosphatase (ALP), Dentine matrix protein 1 (DMP-1), collagen I (Col-I) | Hybrid RGD modified alginate/laponite hydrogel microspheres has a promising potential in vascularized dental pulp regeneration. |
| PEG-modified natural polymers | |||||||
| Galler et al., 2011 [66] | PEGylated fibrin | In vitro In vivo |
PEGylated fibrinogen with added thrombin. | Carboxylated N-hydroxysulfosuccinimide-active ester polyethylene glycol (PEG) (MW = 3400 Da) added to 40 mg/mL of bovine fibrinogen in TRIS- saline at a molar ratio of 10:1. Equal volume of thrombin (200 U/mL in 40 mM CaCl2) was added | Stem cells isolated from human exfoliated deciduous teeth (SHED), DPSCs, periodontal ligament stem cells (PDLSCs), bone marrow mesenchymal stem cells (BMMSCs) |
Col I, Col III, matrix metalloproteinase (MMP-2), bone Sialoprotein (BSP), osteocalcin (OCN), runt-related transcription factor -2 (RUNX2), dentin sialophosphoprotein (DSPP), DMP-1 | ALP activity and osteoblastic and odontoblast differentiation genes were higher in dental stem cells than BMMSCs. SHED and PDLSCs exhibited high expression of collagen, while DPSCs and PDLSCs expressed high levels of differentiation late markers. In vivo, fibrin matrix degraded and replaced by vascularized connective tissue. |
| Lu et al., 2015 [313] | PEG fibrinogen | In vitro | PEG fibrinogen with variable amounts of polyethylene glycol diacrylate (PEGDA) | Increase of PEGDA crosslinker allows for higher modulus but longer times of crosslinking and less swelling ratio | DPSCs | Col I, DSPP, DMP-1, OCN | Odontogenic genes expressions and mineralization were correlated to the hydrogel crosslinking degree and matrix stiffness |
| Jones et al., 2016 [314] | HyStem-C is a commercial hydrogel hyaluronic acid (HA)- PEGDA -gelatin | In vitro | Polyethylene glycol diacrylate with an added disulfide bond (PEGSSDA) with an added disulfide bond. | Hydrogel gelation time decreased as the PEGSSDA crosslinker concentration (w/v) increased from (0.5% to 8.0%) | DPSCs | The PEGSSDA-HA-Gn was biocompatible with human DPSCs. Cell proliferation and spreading increased considerably with adding fibronectin to PEGDA-HA-Gn hydrogels. | |
| Feng et al., 2020 [312] | Polyethylene glycol diacrylate\sodium alginate (PEGDA/SA) | In vitro In vivo |
PEGDA/SA loaded basic fibroblast growth factor (bFGF) (PEGDA/SA-bFGF) | DPSCs | Reduction of mass ratio of PEGDA/SA to 20:1 ~ 15:1 resulted in the formation of a well-organized pulp structure after implantation | ||