Table 2.
Summary of nanocomposite hydrogels from hydrogels and silicon-based NPs for biomedical applications.
| Fillers | Hydrogels | Applications and Functions | Ref. |
|---|---|---|---|
| Silica (SiO2) particles or NPs | HA/PNIPAM | Tissue engineering; SiO2 NPs improve mechanical properties; HA can improve biocompatibility; The stability and the rigidity increase with the amount of PNIPAM | [159] |
| PNIPAM | Drug delivery and tissue engineering; SiO2 NPs improve the thermal and mechanical properties but decrease the swelling ratio | [160,161,162,163,164,165,166,167,168] | |
| PAM | Compression strength and elastic modulus of the composite hydrogels were significantly improved by adding SiO2 NPs compared with pure PAM hydrogels | [169,170,171,172,173] | |
| Silicone | Implantable medical devices; SiO2 can increase swelling behavior and improve stiffness of the hydrogel; Hybrid hydrogel can be used to decrease the protein absorption and the growth of bacteria | [174] | |
| PHEA | Drug delivery; The silica particles were well dispersed in hydrogels; The release rate of aspirin decreased with the increasing content of silica | [175] | |
| PVA | Biomaterials; The tensile strength of PVA hydrogel increased with SiO2 NPs content. Proper content of SiO2 NPs could also enhance the permeability and swelling property, resulting in the improvement of the capillary water absorption capacity of PVA hydrogel | [176] | |
| CS | Bone tissue engineering; SiO2 NPs have a positive effect on cell viability and induce the occurrence of mineralization not only at the surface of the material but also in its entire volume; CS as bioactive injectable systems for bone tissue repair can undergo in situ gelation under physiological temperatures | [177,178] | |
| Peptide | Biosensor; PEG/peptide can form enzyme responsive hydrogel and collapse in response to diverse biological stimuli; The negatively charged silica NPs used are also at a sufficiently high concentration to form a regular periodic structure within the hydrogel, acting as a photonic bandgap which can reflect visible wavelengths of light | [138,140] | |
| Cellulose | Tissue engineering and cell cultures; SiO2 preserves extracellular matrix-like materials and cellular proteins; The intact 3D spheroids can be recovered from the hydrogel by a cellulase enzyme for downstream applications | [179] | |
| PMAA or PAA | SiO2 as adhesive fillers that interacted with PMAA chains can improved viscoelastic moduli (up to 8.7 times) and enhanced elasticity | [180,181] | |
| ALG or COL | Tissue engineering; SiO2 can improve the mechanical properties, including surface roughness and hardness, of the hydrogel | [182,183,184] | |
| PEG | Drug delivery; Hydrogel can form sustained-release depot systems; Incorporation of SiO2 NPs can regulate the pores size, gelation time and viscosity of the hydrogel; The drug loading capacity and drug release profiles could be tuned | [185,186] | |
| MSNs | CS | Drug delivery; MSNs facilitate the drug loading and their subsequent release; CS enables pH-triggered drug release and improves the endocytosis of target cells and cell biocompatibility | [187] |
| Drug delivery; The introduction of MSNs into CS will facilitate the gelation process at body temperature and also promote the elastic modulus; MSNs can load small drug molecules and then steadily release them for a long time period | [178] | ||
| PClAETA | Biomaterials; Introduction of non-functionalized MSNs can improve the water absorption of the hydrogel | [188] | |
| Poly(aspartic acid) | Biomaterials; MSNs as crosslinker can optimize the pore morphology, improve thermal stability increase swelling ratio and enhance salt tolerance of the composite; MSNs can be uniformly and stably dispersed in the structure of the hydrogel | [189] | |
| PNIPAM | Biomaterials; MSNs can be used as effective “topological crosslinkers” to reinforce the PNIPAM hydrogels | [190] | |
| HAP and nBG | GEL | Bone tissue regeneration; HAP significantly improves the stiffness of GEL hydrogels, while it maintains their structural integrity and swelling ratio; Introduction of HAP results in a lower swelling ratio, higher mechanical moduli, and better biocompatibility and promotes cell functional expression for osteon biofabrication; Gelatin hydrogels also provide natural cell binding motifs, making them amenable for 3D cell encapsulation; GEL provide cell-responsive characteristics, cell adhesion sites, and proteolytic degradability | [191,192,193] |
| Silk fibroin | Bone tissue regeneration; HAP can increase compression modulus and mechanical properties, decrease the water uptake ability, improve metabolic and alkaline phosphatase activities of osteoblastic cells; Hydrogel plays regulatory role in oriented nucleation and growth of HAP crystals | [133,194,195,196,197] | |
| PAM | Tissue engineering; SiO2 can improve the mechanical properties, including surface roughness and hardness | [198] | |
| CS | Bone tissue regeneration; HAP enhances swelling, protein adsorption, exogenous biomineralization and osteoblast differentiation and also accelerates bone formation; Zn possessing excellent antimicrobial properties can tackle implant-associated microbial infections; CS can minimize immune response | [199,200,201,202] | |
| PVA | Bone tissue regeneration; Hydrogels are employed as a matrix gel in a mineralization solution; HAP was formed in the polymer matrix under mild conditions, mimicking mineralization in natural bone formation | [132,203,204] | |
| Pullulan | Bone tissue regeneration; Addition of HAP can improve compressive modulus of the scaffold, provide sites for cell adhesion, and render them osteoconductive in vitro; Hydrogels work as scaffolds for mineralization | [205] | |
| PECE | Tissue engineering; PECE endowed hydrogel good thermosensitivity and injectability; HAP can improve mechanical properties of hydrogel | [206] | |
| PEG | Bone substitute material; The formation of HAP in hydrogel matrices enable the acquisition of bioactive composites materials with desired shapes. | [207,208] | |
| ALG | Bone tissue engineering; Incorporation of nBG into hydrogel can combine excellent cellular adhesion, proliferation and differentiation properties, good biocompatibility and predictable degradation rates; ALG can increase lactate dehydrogenase and mitochondrial activity | [135,209,210,211] | |
| CHS | Bone tissue engineering; nBG shows an excellent stimulatory effect on bone formation; CHS improves integration of the nBG to prevent particle migration and promotes bone regeneration; The composite can encapsulate bone marrow to form a mechanically stable construct | [212] | |
| COL | Tissue engineering; Incorporation of nBG NPs improves mechanical stability and enhanced the proliferation rate and osteogenic differentiation | [136,213,214,215] | |
| LAP | GEL/PAM | Tissue engineering; Incorporation of LAP can enhance thermal stability, tensile and stretching properties; GEL can significantly improve the hydrogel’s pH-responsive properties and enhance the antithrombogenicity but decrease the degree of hemolysis of the gels | [216] |
| PEG/GEL | Tissue engineering; Hydrogel remain stable and provide a cell supportive microenvironment under normal cell culture conditions. LAP can preferentially induce osteogenic differentiation of human mesenchymal stem cells | [217] | |
| PEG | Tissue engineering; Incorporation of LAP significantly reduced the cure time while enhancing the adhesive and bulk mechanical properties of the hydrogel; PEG adsorbed onto LAP, forms a compact layer of mostly loops and trains on top of the nanoparticle and large loops around the edge of the particles; PEG elicits minimal inflammatory response and exhibits an enhanced level of cellular infiltration | [218,219] | |
| PAM | Tissue engineering; The incorporation of catechol on the PAM exhibits a strong affinity toward LAP and enhances stiffness and a viscous dissipation property | [220,221,222] | |
| P(MEOMA-OEGMA) | Drug delivery and tissue engineering; LAP as physical cross-linker had significant influence on the microstructure and swelling/deswelling behaviors of hydrogels.; OEGMA can increase equilibrium swelling ratio and water retention; Hydrogel can provide thermosensitivity and the excellent biocompatibility | [223] | |
| P(AM-DMAEMA) | Tissue engineering, cell culture substrates and biosensors; LAP serves as a physical cross-linker and can change the mechanical strength of the hydrogel under direct-current electric field | [224] | |
| PNIPAM | Tissue engineering; LAP can influence the polymeric chain arrangement and increase the mechanical toughness and thermal stability | [225,226] | |
| Pluronic F127 | Tissue engineering; The interactions between LAP and Pluronic F127 may contribute to rearrangements of network structures at high deformations, leading to high elongations and improved toughness | [227] | |
| GMA | Biomaterials; LAP can reinforce mechanical toughness and elasticity; GMA regulates equilibrium swelling ratio and improves water content; Integrating LAP and GMA can improve self-standing ability and rheological, compression, and tensile properties | [228] | |
| MMT | CS | Drug delivery; MMT can enhance the loading of positively charged drug and affect the hydrogel’s drug release mechanism and swelling properties; The hydrogel can be used for controlled- release of drugs | [137,229] |
| CS-g-PAM | Superabsorbent polymer composites; Incorporation of MMT can optimize their absorption capacity, improve their swelling rate and salt-resistant ability; Composites exhibit moderate antibacterial activity in acidic medium | [230] | |
| PAM | Drug delivery; MMT effects the equilibrium swelling and drug release behavior of the composite; MMT can improve the barrier property of nanocomposite hydrogels and decrease the burse effect. MA effects the pH-responsivity on equilibrium swelling and release of drug | [231,232,233] | |
| P(ATC-AM) | Drug delivery; MMT serves as chemical cross-linker to enhance strength and toughness and decrease the swelling degree; ATC is cationic monomer and exist cation- exchange reaction with MMT | [234] | |
| GEL or COL | Drug delivery and wound dressing; Drug intercalation results in changes in MMT layered space; Integration of drug loaded MMT and gelatin creates biodegradable composite hydrogels with controlled drug release property, improved mechanical and thermal properties | [235,236] | |
| PAA or PMA | Biomaterial implants; MMT is used for adsorbing drug, achieving high drug loading; PAA is used for pH/bacteria- responsive releasing | [237] | |
| Polysaccharide | MMT can enhance strength and toughness and decrease the swelling degree | [238] | |
| PNIPAM | Tissue engineering; MMT can influence the polymeric chain arrangement and the pore size and increase the complex viscosity and adhesion strength as well as thermal stability | [239,240,241,242,243] | |
| Other silicate particles | P(AM-IA) | Drug delivery; Incorporation of hectorite offers the hydrogel with suitable water absorbency, shear-resistance, high gel strength and good thermal stability; IA provides pH-responsivity on drug release | [244,245,246] |
| ALG | Drug delivery; Halloysite nanotubes improve complex surface topography and structural integrity and achieve a sustained release of the growth factor; The composites enhance repair and regeneration in damaged or diseased tissues | [139] | |
| PEG/P(AA-VP) | Drug delivery; Phyllosilicate enhances the water uptake with a desirable strength; Hydrogels are used for pH responsible and controlled release | [247] | |
| PCL-PEG-PCL | Bone regeneration; Mesoporous magnesium silicate can enhance the compressive strength, elastic modulus, and hydrophilicity of hydrogel, and promote cell attachment and proliferation and increase the degradability of the hydrogel | [248] | |
| PAM | Tissue engineering; Attapulgite nanorods grafted with vinyl groups serve as macro-crosslinkers, which can significantly increase the modulus, strength, and toughness of hydrogels; | [249] | |
| P(AA-NIPAM) | Tissue engineering; The presence of imogolite nanotubes produced strong hydrogels that exhibit thermo-responsive volume transition because of the coil/globule transition of PNIPAM chains. | [250] |
Mesoporous silica nanoparticles (MSNs); Hydroxyapatite (HAP); Poly[(2-acryloyloxyethyl) trimethylammonium chloride] (PClAETA); Zinc-doped chitosan (Zn-CS); nano-scaled bioactive Glass (nBG); Chondroitin sulfate (CHS); Laponite (LAP); 2-(2-methoxyethoxy) ethyl methacrylate (MEOMA); oligo(ethylene glycol) methacrylate (OEGMA); Guanidinium-pendant methacrylamide (GMA); Montmorillonite (MMT); Poly(acrylamide-co-maleic acid) (P(AM-MA)); (3-acrylamidopropyl) trimethylammonium chloride (ATC); Poly(ε-caprolactone)-poly(ethylene glycol)–poly(ε-caprolactone) copolymer (PCEC); Poly(acrylamide-co-itaconic acid) (P(AM-IA)); Poly(acrylic acid-co-vinyl pyrrolidone) (P(AA-co-VP)); Poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL).