Table 3.
Smart/stimuli-responsive hydrogels employed for different biomedical applications.
| Type of smart/stimuli-responsive hydrogel | Smart/stimuli-responsive hydrogel polymer | Smart/stimuli-responsive hydrogel system | Stimuli | Biomedical applications | Year | Refs. | |
|---|---|---|---|---|---|---|---|
| Physical-responsive hydrogels | Temperature-responsive hydrogels | -Poly(N-isopropylacrylamide) (PNIPAAm) | -PNIPAAM covalently grafted onto a flat substrate that forms the bottom of the microfluidic device | -Temperature | -Microfluidic actuators | 2018 | [332] |
| -Methylacrylate gelatin (GelMA) | -GelMA-PDA-ASP nanocomposite hydrogels | -Temperature | -Dressing to enhance skin wound healing -Targeted delivery of ASP |
2021 | [333] | ||
| -Polyacrylamide (PAAM) -Poly(N-isopropylacrylamide) (PNIPAAm) |
-CNW–PAAm–PNIPAm nanocomposites | -Temperature -PH |
-Promising for different biomedical applications | 2015 | [222] | ||
| -Poly(N-isopropylacrylamide) (PNIPAAm)-Hydrophobically associated polyacrylamide (HAPAM) hydrogel (HAPAM-PNIPAAM) | -Mxene-HAPAM-PNIPAAM nanocomposite double-network hydrogel | -Temperature -Compression/stress |
-Smart compression biosensors | 2019 | [192] | ||
| Light/photo-responsive hydrogels | -Polyacrylamide (PAAM) | -Conducting polymer hydrogel (CPH) based on copolymerized PANI and PAM (PAM/PANI CPH) | -NIR light | -Neural tissue engineering | 2020 | [334] | |
| -Poly(N-isopropylacrylamide) (PNIPAAM) | -Poly(diketopyrrolopyrrole-alt-3,4 ethylenedioxythiophene)-PNIPAAm | -NIR light | -Targeted and controlled drug delivery for cancer treatment | 2017 | [136] | ||
| -Poly(N,N-dimethylacrylamide (PDMA) | -PDMA/Coumarin copolymers | -Photo/light | -Promising for different biomedical applications | 2018 | [125] | ||
| Electric-responsive hydrogels | -Carboxymethyl chitosan (CMCH) -Poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer layer |
-Conductive hydrogels (PEDOT/CMCH) | -Electric field | -Neural Tissue engineering | 2018 | [335,336] | |
| -Chitosan (CH) | -PAAM–CH–PPy | -Electric field | -Biosensors -Tissue engineering -Drug Delivery |
2018 | [149] | ||
| Magnetic-responsive hydrogels | -Methylacrylate gelatin (GelMA) | -GelMA-SPIONs nanocomposites | -Magnetic | -Promising for different biomedical applications -3D printing |
2020 | [170] | |
| -N-isopropylacrylamide (NIPAAM) -Polyacrylamide (PAAM) |
-Nanocomposite hydrogel system (NIPAAm–AAm–PEDGA and MNPs) | -Magnetic | -Microactuators | 2016 | [174] | ||
| -Polyethylene glycol (PEG) | -Janus microparticle-PEG nanocomposites | -Magnetic | -Microactuators and robotics -3D printing |
2021 | [173] | ||
| Pressure/strain-responsive hydrogels | -Poly(acrylamide-co-Lauryl Methacrylate) (P(AAM-co-LMA)) | -Hybrid Latex Nanoparticles (HLPs) crosslinked P(AAM-co-LMA) | -Pressure/strain | -Wearable biosensors | 2019 | [191] | |
| -Carboxy Meyhylcellulose (CMC) -Polyacrylamide (PAAM) |
-PAAm/CMC semi-interpenetrating network hydrogel | -Pressure/strain | Strain sensors | 2020 | [190] | ||
| Ultrasound-responsive hydrogels | -Alginate (Alg.) | -Ionic crosslinked Alginate hydrogels (Calcium Alginate hydrogels) | -Ultrasound | Drug delivery | 2014 | [202] | |
| -Polyethylene Glycol (PEG) | -Sericin/hydrogel scaffold | -Ultrasound | Drug delivery | 2019 | [199] | ||
| Chemical-responsive hydrogels | PH-responsive hydrogels | -Poly(acrylamidoglycolic acid) (PAGA) | -Poly(acrylamidoglycolic acid) based nanocomposite (PAGA-NC) | -PH | -Drug Delivery | 2017 | [229] |
| -Poly(methacryloyloxyethyl phosphorylcholine-co-4-formylbenzoate ethyl methacrylate) P(MPC-co-FBEMA) copolymers |
-P(MPC-co-FBEMA)-ASNP nanocomposite hydrogels | -PH | -Controlled drug delivery | 2020 | [232] | ||
| -Collagen (Col) | -Col-JK-1 | -PH -Enzyme (MMPs) |
-Tissue engineering -Drug delivery |
2019 | [337] | ||
| -Chitosan (CH) | -CH/CG composite | -PH -Salt |
Cartilage Tissue Engineering | 2018 | [338] | ||
| -pre-gel hydrogel solution 80 mol% acrylamide, 8 mol% 3-acrylamidophenylboronic acid, 10 mol% N-[3-(dimethylamino)propyl]methacrylamide, 2 mol% N,N′-methylenebisacrylamide | -Three-layered microfluidic sensing device: Bottom: polycarbonate Center: polyvinyl chloride (PVC) Top: another layer of polycarbonate and the smart hydrogel pillars in the microfluidic channels |
-PH | -sensors for monitoring disease biomarkers or environmental contaminants in drinking water | 2018 | [339] | ||
| Glucose-responsive hydrogels | -Phenylboronic acid-grafted γ-Polyglutamic acid (PBA-PGA) | -KGM/PBA-PGA | -Glucose | -Drug Delivery | 2021 | [248] | |
| -Poly(N-vinylpyrrolidone-co-dimethylamino)ethyl acrylate-co-3-(acrylamido)PBA (P(NVP-co-DMAEA-co-3APBA)) - Ethylene glycol dimethacrylate (EGDMA) |
-GR-MN (Glucose-responsive microneedle patch) based on p(NVP-co-DMAEA-co-3APBA) | -Glucose | -Drug Delivery | 2020 | [254] | ||
| Ionic strength and Redox-responsive hydrogels | -Polyethylene Glycol (PEG) | -Poly(ethyleneglycol)-block-poly(γ-propargyl-l-glutamate) (PEG-PPLG) | -Redox -Temperature |
-Promising for different biomedical applications | 2017 | [269] | |
| -Gelatin -Chitosan (CH) |
-Gelatin-chitosan double crosslinked networks | -Ionic strength | -Drug delivery | 2011 | [260] | ||
| Biological-responsive hydrogels | Enzyme-responsive hydrogels | -Hyaluronic Acid (HA) -Gelatin |
-Tyramine conjugated HA (TA-HA) and gelatin | -Enzyme | -Tissue engineering -Drug delivery |
2018 | [340] |
| -Polypeptides (PLys-b-(PHIS-co-PBLG)-PLys-b-(PHIS-co-PBLG)-b-Plys) | -Pentablock terpolypeptide of the type PLys-b-(PHIS-co-PBLG)-PLys-b-(PHIS-co-PBLG)-b-PLys | -Enzyme -PH |
-Drug delivery | 2018 | [341] | ||
| -Chitosan (CH) | -Alanyl-alanyl-phenylalanine-7-amido-4-methylcoumarin (AAP-AMC) covalently conjugated to chitosan | -Enzyme | -Biosensors -Tissue engineering |
2014 | [305] | ||
| Antigen/antibody-responsive hydrogels | -Polyacrylamide (PAAM) | - Bio-conjugated polyacrylamide-based hydrogel (HBPAAm hydrogel) | -Antigen | -Biosensors | 2020 | [322] | |
| -N-(9-fluorenylmethoxycarbonyl)-L, l-diphenylalanine (Fmoc-FF) | -Peptide hydrogels encapsulating leishmania antigen (N-(9-fluorenylmethoxycarbonyl)-L, l-diphenylalanine (Fmoc-FF) encapsulating leishmania antigen) | -Antigen | -Biosensors | 2017 | [325] | ||
ASP, Aspirin; CNW, Cellulose nanowiskers; PANI, polyaniline; PPY, polypyrrole; SPIONs, Superparamagnetic iron oxide nanoparticles; ASNP, Silica nanoparticles; CG, Carrageenan; KGM, Konjac glucomannan.