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Tran, T.S.;  Balu, R.;  Mettu, S.;  Choudhury, N.R.;  Dutta, N.K. 4D Printable Smart Hydrogels for Drug Delivery. Encyclopedia. Available online: https://encyclopedia.pub/entry/31927 (accessed on 20 June 2024).
Tran TS,  Balu R,  Mettu S,  Choudhury NR,  Dutta NK. 4D Printable Smart Hydrogels for Drug Delivery. Encyclopedia. Available at: https://encyclopedia.pub/entry/31927. Accessed June 20, 2024.
Tran, Tuan Sang, Rajkamal Balu, Srinivas Mettu, Namita Roy Choudhury, Naba Kumar Dutta. "4D Printable Smart Hydrogels for Drug Delivery" Encyclopedia, https://encyclopedia.pub/entry/31927 (accessed June 20, 2024).
Tran, T.S.,  Balu, R.,  Mettu, S.,  Choudhury, N.R., & Dutta, N.K. (2022, October 31). 4D Printable Smart Hydrogels for Drug Delivery. In Encyclopedia. https://encyclopedia.pub/entry/31927
Tran, Tuan Sang, et al. "4D Printable Smart Hydrogels for Drug Delivery." Encyclopedia. Web. 31 October, 2022.
4D Printable Smart Hydrogels for Drug Delivery
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Hydrogels are three-dimensional crosslinked polymer network structures that can absorb and hold a large quantity of water while retaining a distinct shape. Among modern drug formulations, stimuli-responsive hydrogels, also known as "smart hydrogels," has attracted enormous attention. The fundamental characteristic of these systems is the capacity to change their mechanical properties, swelling capacity, hydrophilicity, permeability of bioactive molecules, etc., in response to a wide range of stimuli, including temperature, pH, light irradiation, magnetic field, biological factors, etc. On the other hand, the expeditious development of 3D printing technologies has revolutionized the fabrication of hydrogel systems for biomedical applications. By combining these two aspects, 4D printing (i.e., 3D printing of smart hydrogels) has emerged as a new promising platform for the development of novel drug delivery systems, which release active ingredients in response to internal or external stimuli.

3D printing 4D printing stimuli-responsive polymers

1. Introduction

Hydrogels are three-dimensional (3D) crosslinked polymer network structures that can absorb and hold a large quantity of water while retaining a distinct shape. Hydrogels can be classified as natural or synthetic (based on the polymer source), physical or chemical (based on the crosslinking type), ionic or non-ionic (based on electric charge), nanoporous or microporous (based on the pore size), nano- or micro- or macro-gels (based on the overall size), and conventional or smart hydrogels (based on stimuli-responsiveness) [1]. Among them, smart hydrogels have recently attracted significant attention owing to their capacity to alter the shape, volume, structure, properties, and functions in response to external stimuli. Smart hydrogels offer several advantages over conventional hydrogels, such as high specificity, good controllability, multi-functionality, tuneability, excellent spatial and temporal resolution, and remote modulation [2]. In the last two decades, smart hydrogels have been extensively studied for healthcare, agriculture, environment, biosensing, tissue engineering, and drug delivery applications [3].
Since the first three-dimensional (3D) printing system was introduced in 1986, the manufacturing industry that adopted 3D manufacturing has undergone dramatic changes; requiring less time, energy, and less waste due to the ability to directly fabricate 3D prototypes from computer-aided designs (CAD) [4]. Over the past several decades, 3D printing technology has made significant progress in healthcare, enabling the fabrication of patient-specific scaffolds/constructs with defined features [5]. It is a highly effective approach for fabricating three-dimensional hydrogels with precise control over their shape and size, structure, and morphology for use in tissue engineering and drug delivery applications.
Currently, the majority of 3D printed biomaterials/hydrogels for healthcare applications are static and unable to change/transform in response to dynamic changes in the body’s internal environment and biological cues [6]. Advances in dynamic materials, which have the capability to respond to external stimuli over a certain period of time, have opened up new dimensions for engineering future healthcare products [7]. While 3D printing technology has revolutionized the modern manufacturing sector, it becomes even more advantageous when “time” is incorporated as the fourth dimension. With this extra dimension, 3D printed objects can change shape on their own in response to external stimuli such as light, heat, electricity, magnetic fields, and so on [8][9]. 3D printing of such time-dependent, programmable, and intelligent dynamic materials is referred to as 4D printing [10]. Compared to the traditional 3D printed hydrogels, the 4D printed systems can interact with the surrounding environment by responding to stimuli with various outputs including shape-morphing, mechanical motions and biological responses [11]. As a result, 3D printed smart hydrogels (or 4D printed hydrogels) have piqued a surge in interest from both academia and industry for various applications. A brief history of the voyage from the first crosslinked polymer network to the 4D printed hydrogels for drug delivery applications is illustrated in Figure 1.
Figure 1. A brief history of the 4D printed smart hydrogels for drug delivery applications. Created with BioRender.com.

2. Material Design: Development of 4D Printable Smart Hydrogels for Drug Delivery

Since the description of the first crosslinked hydrophilic polymer more than 50 years ago [12], the systematic design of hydrogels has advanced from static, bioinert hydrophilic polymer networks to dynamic, bioactive hydrogel systems capable of directing specific biological responses such as cellular ingrowth during wound healing and on-demand drug delivery [13].
Within the human body, the biological systems continuously adapt and respond to the dynamic surrounding environments and biological cues. This sophisticated adaptability is accomplished by perceiving and responding to signals like light fluctuations, daily temperature, or biochemical traces. Thus, a necessary initial step in creating smart hydrogel systems for healthcare is to understand the synthesis and processing of constituent hydrogel materials that can expand or contract in response to a variety of stimuli. Based on the kind of external stimulus required for on-demand actuation, researchers may categorize various stimuli-responsive hydrogels into six major groups, including heat (temperature), magnetic fields, electrical voltage/current, light, pH of the media, and water [2]. The responsiveness and manipulation of hydrogel design under these stimuli opens the door to the development of a variety of 4D printed hydrogels for targeted therapeutic applications. This section highlights aspects of the development of stimuli-responsive biomaterials by analyzing the mechanisms used to transform hydrogel structures when designing dynamically responsive smart hydrogels feasible for 4D printing.

2.1. Thermo-Responsive Hydrogels

A temperature fluctuation, particularly in the 36–38 °C range that corresponds to the human body, or ambient settings, is an enticing stimulus for controlling transformer hydrogels. Thermo-responsive hydrogels exhibit temperature-dependent phase behavior and can undergo a sharp sol-gel transition at a critical temperature [14][15][16]. There are two types of thermo-responsive hydrogels: lower critical solution temperature (LCST) hydrogels, which shrink with the rising of temperature above a critical point, whereas upper critical solution temperature (UCST) is the upper bound to a temperature range of partial miscibility. 3D printing of such thermo-responsive hydrogels is an attractive route to create 4D printed hydrogels, which are conceivable to the temperature of the surroundings, for on-demand drug delivery applications.
The literature on LCST hydrogels is dominated by poly(N-isopropyl acrylamide) (pNIPAM) and its derivatives, because of its massive volume change at a relatively low critical temperature of around 32 °C [23][24][25]. The biocompatibility and ease of processing of pNIPAM are demonstrated in a recent work by Allen and co-workers [26] by culturing 3T3 fibroblasts on cell sheets produced from aligned electrospun fibers, demonstrating the promising prospect of pNIPAM for 4D printing toward drug delivery applications. Thermal responsive pNIPAM-based hydrogels with tunable responsiveness (critical temperature and swelling characteristics) have been developed by adjusting the number of repeating monomer units in (oligoethylene glycol methacrylate) (OEGMA) [27], or by combining it with polymers such as poly[di(ethylene glycol) ethyl ether acrylate] (PDEGA) [28]. In contrast, UCST hydrogels expand as the temperature rises. This positive thermal responsivity broadens the design space for future smart hydrogels. The most frequently employed UCST hydrogels are interpenetrating networks of polyacrylamide (pAAm) and polyacrylic acid (pAAc) [29][30]. Recent research also showed that smart biomaterials, such as highly elastic protein elastic and elastin-mimetic proteins; resilin and resilin-mimetic proteins can be designed to exhibit tunable LCST and UCST transitions in physiological solutions [31][32]. Extensive research by Dutta et al. and others [31][33][34][35] has demonstrated that resilin and resilin-mimetic proteins can exhibit tunable multi-stimuli-responsiveness including both LCST and UCST.
Significant research efforts have also been focused on enhancing the biocompatibility and biodegradability of thermo-responsive hydrogels. Ye and co-workers [36] have developed a supramolecular UCST hydrogel for sustained-release drug administration and tissue engineering scaffold using polyglycerol sebacate (pGS), a novel biodegradable elastomeric material with outstanding biocompatibility. Greater biodegradability can be achieved by the use of hydrolytically and enzymatically labile bonds [36], or by introducing biodegradable monomers like benzomethylene dioxepane or methacrylate polylactide into their polymeric backbone [37][38]. Natural polymers such as gelatine, cellulose, and chitosan can also be functionalised with poly(L-alanine-co-L-phenylalanine), poly(ethylene glycol), and glycerol phosphate to form smart hydrogels that are both thermal responsive and biodegradable [39][40], promising for 4D printed drug delivery systems.

2.2. Magnetic Responsive Hydrogels

The magnetic field has also been studied as a potential external trigger for controlling the properties of smart hydrogels. The ability to activate remote actuation with a fast response time and biocompatibility even at high field strength makes electromagnetic a favorable stimulus, especially in vivo applications. To achieve magnetic responsiveness in hydrogels, exogenous additives like paramagnetic or ferromagnetic are included in the polymeric matrix, allowing for rapid and large actuation behaviors in response to magnetic fields [41]. Magnetic additives such as metal alloys (e.g., iron and neodymium alloy), metal oxides (e.g., ferrous ferric oxide), and functionalized magnetic nanoparticles can be coupled with pNIPAM, pAAm and gelatin in a chemically or physically crosslinked polymer network to form magnetically responsive smart hydrogels [42][43][44]. More complex magnetic responsive hydrogels with stronger interactions between the magnetic particles and the polymer network were also created via covalent and coordination bonds [45]. These hydrogel systems, in general, do not require extra crosslinkers during synthesis and gelation occurs spontaneously when mixed [18].
There are two main action modes in magnetic responsiveness in hydrogels for controlled drug release, that are changing the direction of the magnetic field to arrange perpendicularly or parallelly to the drug diffusion direction and switching on/off the magnetic field to trigger release [46][47][48]. Several magnetic responsive smart hydrogels are currently being tested in vivo in animal models and have the potential to translate to clinical drug delivery applications [49][50].

2.3. Electrical Responsive Hydrogels

Inspired by artificial muscle biomimicry, electrical responsive hydrogels can expand or contract under a solvent-induced or an externally applied electrical field [51][52]. The use of an external electrical field as a stimulus has particular advantages for drug delivery due to quick, precise, and programmable responsiveness [53][54].
For the controlled release of drug, electrical responsive hydrogels are fundamentally based on the mobility of ions in response to an electrical field and the rearrangement of the ion concentration profile at the hydrogel-swelling media interface. Equilibrium is achieved through the balance of fixed charges on the polymer backbone and counterions attracted by the surrounding swelling media. As a result, the ion concentration is not uniformly distributed inside and outside the gel, creating an osmotic pressure that causes swelling or deswelling [19].
Electrical responsive hydrogels are typically polyelectrolytes with ionizable groups along their side chains or polymeric backbone [55][56]. Numerous synthetic polyelectrolytes and related copolymers have been utilized to fabricate electrical responsive hydrogels, including poly (vinyl alcohol) (PVA) [57], poly(sodium maleate-co-sodium acrylate) [58], PVA/pAAc [59], pAAc/poly(N-vinylpyrrolidone) [60], and sulfonated polystyrene (s-PS) [61]. There are also natural polyelectrolytes, including proteins [62][63], polysaccharides [64], and polypeptides [65], that respond to electrical stimuli [66][67][68]. They can be combined with synthetic polymers to create hybrid electrical responsive hydrogels, for instance, fibrin protein blended with pAAc [69], chitosan coupled with poly(N,N-dimethylacrylamide) [70], and alginate combined with poly(methacrylic acid) [71] for 4D printed drug delivery systems.

2.4. Photo-Responsive Hydrogels

The use of light as a stimulus is particularly advantageous for remotely inducing the expansion and contraction of 4D printed hydrogels for controlled delivery of therapeutic agents. The two primary mechanisms of photo-responsive hydrogels are based on reversible crosslinking and photothermal excitation [20]. Both approaches can be accomplished by including photoactive moieties into the hydrogel matrix [20]. For reversible crosslinking, the presence of photoactive moieties such as azobenzene or o-nitrobenzyl groups can induce the photocleavage or photoisomerization of hydrogel matrices upon illumination, resulting in reversible contraction–expansion of polymer chains [72][73]. A second way to achieve light-induced deformation is by employing photothermal nanomaterials, which rapidly convert light irradiation to heat dissipation, to control the reversible dehydration–hydration processes of the photo-responsive hydrogels [74][75].
Numerous nanomaterials, including inorganic nanomaterials (e.g., gold and neodymium oxide) [76], carbon-based materials [77], and black phosphorus [74], have been introduced into photo-responsive hydrogels. Researchers have demonstrated photoresponsivity by incorporating gold nanorods into pNIPAM-AAc hydrogels [78], others reported smart hydrogels (agarose and pNIPAM) containing single-walled nanocarbons (SWNTs) and single-walled nanohorns (SWNHs) that show marked phase transitions upon NIR irradiation [79][80]. Additive manufacturing of such intelligent photo-responsive hydrogels is still in its infancy yet promising for 4D printed drug delivery systems.

2.5. pH Responsive Hydrogels

Apart from physical stimuli, physiological conditions (e.g., the inherently low pH of the stomach, or the slightly alkaline condition of the blood) have been exploited to initiate swelling-controlled drug release from hydrogel carriers [81]. Systems that are capable of responding to a dynamic pH environment are useful for healthcare applications, as various places throughout the human body experience pH variations during a disease condition. The dynamic pH ranges in various tissues and cellular compartments in the human body are detailed in Table 1 [82].
Table 1. pH in various tissues and cellular compartments [82].
The pH sensitivity of a hydrogel network can be modified by adjusting the hydrophilicity and ionic character of the internal pendant functional groups [21]. It has been demonstrated that hydrogels containing acidic moieties swell as the acid groups deprotonate at higher pH. Cationic groups, on the other hand, generate more swelling at lower pH values [83]. Thus, there are two major types of pH-responsive hydrogels: anionic and cationic hydrogels. Anionic hydrogels contain pendant groups that ionize at a pH greater than their acid dissociation constant (pKa) and expand at higher (primarily basic) pH values. Due to the presence of physical interactions between the polymer chains, their polymer networks remain folded at pH values less than their pKa (low-pH environment). Conversely, cationic hydrogels expand when the pH level falls below pKa and contract when the pH value rises over pKa [84].
Anionic hydrogels are frequently constructed of crosslinked polymer networks containing carboxyl groups (polyacrylic acid [85], polymethacrylic acid [86], and polycarboxymethyl agarose [87]) and their copolymers [88]. Monomers bearing amine and amide groups, such as AAm [89], dimethylaminoethyl methacrylate (DMAEMA) [90], and 2-(diethylamino)ethyl methacrylate (DEAEMA) [91], as well as their copolymers [92], are commonly used as constituents of cationic hydrogels. Emerging hydrogels made of biopolymers such as alginate [93], gelatine [94], chitosan [95], and albumin [96], resilin-mimetic proteins [68], silk [97], soy protein [98], and their blends and composites could also exhibit pH responsiveness with superior biocompatibility and biodegradability compared to their synthetic counterparts. With the dynamic pH ranges in various tissues and cellular compartments in the human body, 4D printed pH-responsive hydrogels are advantageous for precisely controlled drug release into a specific area of the human body under a specific condition.

2.6. Water Responsive Hydrogels

Water responsive hydrogels, or superabsorbent polymers, are crosslinked three-dimensional interconnected macromolecular networks possessing extremely high liquid swelling capacity, providing an effective vehicle for therapeutic agents to be encapsulated and released in biological environments. Water-responsive hydrogels are often composed of ionic monomers and are weakly crosslinked. As a result, they exhibit an extraordinary capacity for water absorption [99][100]. Water-responsive hydrogels have been the most commercially successful members of the hydrogel family and are widely used in healthcare products, including pharmaceuticals, personal hygiene, wound dressing, and drug delivery applications [101][102].
At present, the majority of water responsive hydrogels are mostly synthetic or petrochemical in origin, and they are predominantly composed of acrylic monomers, most frequently acrylamide (AAm) [103], acrylic acid (AAc) [104], and their copolymers [105]. In recent years, the trend towards substituting “greener” alternatives in water responsive hydrogels is more and more pronounced due to the low degradability and biocompatibility of the synthetic incumbents. As a result, emerging bio-based water responsive hydrogels are being made from renewable raw materials such as cellulose [106][107], soy protein [108][109], starch [110], natural gums [111], chitin [112] and their hybrids and composites, providing a customizable and effective route toward 4D printed hydrogels for drug delivery applications.

References

  1. Ullah, F.; Othman, M.B.H.; Javed, F.; Ahmad, Z.; Akil, H.M. Classification, processing and application of hydrogels: A review. Mater. Sci. Eng. C 2015, 57, 414–433.
  2. Shi, Q.; Liu, H.; Tang, D.; Li, Y.; Li, X.; Xu, F. Bioactuators based on stimulus-responsive hydrogels and their emerging biomedical applications. NPG Asia Mater. 2019, 11, 64.
  3. El-Husseiny, H.M.; Mady, E.A.; Hamabe, L.; Abugomaa, A.; Shimada, K.; Yoshida, T.; Tanaka, T.; Yokoi, A.; Elbadawy, M.; Tanaka, R. Smart/stimuli-responsive hydrogels: Cutting-edge platforms for tissue engineering and other biomedical applications. Mater. Today Bio 2022, 13, 100186.
  4. Chua, C.K.; Leong, K.F. 3D Printing and Additive Manufacturing: Principles and Applications (with Companion Media Pack)-of Rapid Prototyping; World Scientific Publishing Company: Singapore, 2014.
  5. You, S.; Li, J.; Zhu, W.; Yu, C.; Mei, D.; Chen, S. Nanoscale 3D printing of hydrogels for cellular tissue engineering. J. Mater. Chem. B 2018, 6, 2187–2197.
  6. He, Y.; Yang, F.; Zhao, H.; Gao, Q.; Xia, B.; Fu, J. Research on the printability of hydrogels in 3D bioprinting. Sci. Rep. 2016, 6, 29977.
  7. Rivera-Tarazona, L.K.; Campbell, Z.T.; Ware, T.H. Stimuli-responsive engineered living materials. Soft Matter 2021, 17, 785–809.
  8. Mao, Y.; Ding, Z.; Yuan, C.; Ai, S.; Isakov, M.; Wu, J.; Wang, T.; Dunn, M.L.; Qi, H.J. 3D printed reversible shape changing components with stimuli responsive materials. Sci. Rep. 2016, 6, 24761.
  9. Boydston, A.; Cao, B.; Nelson, A.; Ono, R.; Saha, A.; Schwartz, J.; Thrasher, C. Additive manufacturing with stimuli-responsive materials. J. Mater. Chem. A 2018, 6, 20621–20645.
  10. Tibbits, S. 4D printing: Multi-material shape change. Archit. Des. 2014, 84, 116–121.
  11. Champeau, M.; Heinze, D.A.; Viana, T.N.; de Souza, E.R.; Chinellato, A.C.; Titotto, S. 4D printing of hydrogels: A review. Adv. Funct. Mater. 2020, 30, 1910606.
  12. Peppas, N.A.; Merrill, E.W. Crosslinked poly (vinyl alcohol) hydrogels as swollen elastic networks. J. Appl. Polym. Sci. 1977, 21, 1763–1770.
  13. Li, J.; Mooney, D.J. Designing hydrogels for controlled drug delivery. Nat. Rev. Mater. 2016, 1, 16071.
  14. Andersson, M.; Axelsson, A.; Zacchi, G. Swelling kinetics of poly (N-isopropylacrylamide) gel. J. Control. Release 1998, 50, 273–281.
  15. Bischofberger, I.; Trappe, V. New aspects in the phase behaviour of poly-N-isopropyl acrylamide: Systematic temperature dependent shrinking of PNiPAM assemblies well beyond the LCST. Sci. Rep. 2015, 5, 15520.
  16. Li, Z.; Shen, J.; Ma, H.; Lu, X.; Shi, M.; Li, N.; Ye, M. Preparation and characterization of pH-and temperature-responsive nanocomposite double network hydrogels. Mater. Sci. Eng. C 2013, 33, 1951–1957.
  17. Matsumoto, K.; Sakikawa, N.; Miyata, T. Thermo-responsive gels that absorb moisture and ooze water. Nat. Commun. 2018, 9, 2315.
  18. Li, Z.; Li, Y.; Chen, C.; Cheng, Y. Magnetic-responsive hydrogels: From strategic design to biomedical applications. J. Control. Release 2021, 335, 541–556.
  19. Merino, S.; Martin, C.; Kostarelos, K.; Prato, M.; Vazquez, E. Nanocomposite hydrogels: 3D polymer–nanoparticle synergies for on-demand drug delivery. ACS Nano 2015, 9, 4686–4697.
  20. Li, L.; Scheiger, J.M.; Levkin, P.A. Design and applications of photoresponsive hydrogels. Adv. Mater. 2019, 31, 1807333.
  21. Zixuan, C.; Bin, Z.; Liyang, J.; Yunyi, L.; Guohe, X.; Jingjun, M. Intelligent-Responsive Hydrogels-Based Controlled Drug Release Systems and Its Applications. Prog. Chem. 2019, 31, 1653.
  22. Lee, H.; Wong, H.; Buenfeld, N. Self-sealing of cracks in concrete using superabsorbent polymers. Cem. Concr. Res. 2016, 79, 194–208.
  23. Schild, H.G. Poly (N-isopropylacrylamide): Experiment, theory and application. Prog. Polym. Sci. 1992, 17, 163–249.
  24. Shimizu, T.; Yamato, M.; Kikuchi, A.; Okano, T. Cell sheet engineering for myocardial tissue reconstruction. Biomaterials 2003, 24, 2309–2316.
  25. Cheng, Y.; Ren, K.; Yang, D.; Wei, J. Bilayer-type fluorescence hydrogels with intelligent response serve as temperature/pH driven soft actuators. Sens. Actuators B Chem. 2018, 255, 3117–3126.
  26. Allen, A.C.; Barone, E.; Cody, O.; Crosby, K.; Suggs, L.J.; Zoldan, J. Electrospun poly (N-isopropyl acrylamide)/poly (caprolactone) fibers for the generation of anisotropic cell sheets. Biomater. Sci. 2017, 5, 1661–1669.
  27. Porsch, C.; Hansson, S.; Nordgren, N.; Malmström, E. Thermo-responsive cellulose-based architectures: Tailoring LCST using poly (ethylene glycol) methacrylates. Polym. Chem. 2011, 2, 1114–1123.
  28. Ma, L.; Tang, H.; Wu, P. Volume Phase Transition Mechanism of Poly -Based Microgels Involving a Thermosensitive Poly (ionic liquid). Langmuir 2017, 33, 12326–12335.
  29. Katono, H.; Maruyama, A.; Sanui, K.; Ogata, N.; Okano, T.; Sakurai, Y. Thermo-responsive swelling and drug release switching of interpenetrating polymer networks composed of poly (acrylamide-co-butyl methacrylate) and poly (acrylic acid). J. Control. Release 1991, 16, 215–227.
  30. Koetting, M.C.; Peters, J.T.; Steichen, S.D.; Peppas, N.A. Stimulus-responsive hydrogels: Theory, modern advances, and applications. Mater. Sci. Eng. R Rep. 2015, 93, 1–49.
  31. Dutta, N.K.; Truong, M.Y.; Mayavan, S.; Roy Choudhury, N.; Elvin, C.M.; Kim, M.; Knott, R.; Nairn, K.M.; Hill, A.J. A genetically engineered protein responsive to multiple stimuli. Angew. Chem. 2011, 123, 4520–4523.
  32. Quiroz, F.G.; Chilkoti, A. Sequence heuristics to encode phase behaviour in intrinsically disordered protein polymers. Nat. Mater. 2015, 14, 1164–1171.
  33. Balu, R.; Dutta, N.K.; Dutta, A.K.; Choudhury, N.R. Resilin-mimetics as a smart biomaterial platform for biomedical applications. Nat. Commun. 2021, 12, 149.
  34. Balu, R.; Dutta, N.K.; Choudhury, N.R. Resilin-mimetic Polypeptides and Elastomeric Modular Protein Polymers: Amino Acid Sequence, Conformational Ensemble, and Stimuli Responsiveness. In Biomimetic Protein-Based Elastomers: Emerging Materials for the Future; Royal Society of Chemistry: London, UK, 2022; Volume 10, p. 108.
  35. Choudhury, N.R.; Liu, J.C.; Dutta, N.K. Biomimetic Protein-Based Elastomers: Emerging Materials for the Future; Royal Society of Chemistry: London, UK, 2022.
  36. Ye, H.; Owh, C.; Loh, X.J. A thixotropic polyglycerol sebacate-based supramolecular hydrogel showing UCST behavior. Rsc Adv. 2015, 5, 48720–48728.
  37. Siegwart, D.J.; Bencherif, S.A.; Srinivasan, A.; Hollinger, J.O.; Matyjaszewski, K. Synthesis, characterization, and in vitro cell culture viability of degradable poly (N-isopropylacrylamide-co-5, 6-benzo-2-methylene-1, 3-dioxepane)-based polymers and crosslinked gels. J. Biomed. Mater. Res. Part A Off. J. Soc. Biomater. Jpn. Soc. Biomater. Aust. Soc. Biomater. Korean Soc. Biomater. 2008, 87, 345–358.
  38. Nelson, D.M.; Ma, Z.; Leeson, C.E.; Wagner, W.R. Extended and sequential delivery of protein from injectable thermoresponsive hydrogels. J. Biomed. Mater. Res. Part A 2012, 100, 776–785.
  39. Kang, E.Y.; Moon, H.J.; Joo, M.K.; Jeong, B. Thermogelling chitosan-g-(PAF-PEG) aqueous solution as an injectable scaffold. Biomacromolecules 2012, 13, 1750–1757.
  40. Cheng, Y.-H.; Yang, S.-H.; Lin, F.-H. Thermosensitive chitosan-gelatin-glycerol phosphate hydrogel as a controlled release system of ferulic acid for nucleus pulposus regeneration. Biomaterials 2011, 32, 6953–6961.
  41. Ding, M.; Jing, L.; Yang, H.; Machnicki, C.; Fu, X.; Li, K.; Wong, I.; Chen, P.-Y. Multifunctional soft machines based on stimuli-responsive hydrogels: From freestanding hydrogels to smart integrated systems. Mater. Today Adv. 2020, 8, 100088.
  42. Shankar, A.; Safronov, A.P.; Mikhnevich, E.A.; Beketov, I.V. Multidomain iron nanoparticles for the preparation of polyacrylamide ferrogels. J. Magn. Magn. Mater. 2017, 431, 134–137.
  43. Zrínyi, M.; Barsi, L.; Büki, A. Deformation of ferrogels induced by nonuniform magnetic fields. J. Chem. Phys. 1996, 104, 8750–8756.
  44. Messing, R.; Frickel, N.; Belkoura, L.; Strey, R.; Rahn, H.; Odenbach, S.; Schmidt, A.M. Cobalt ferrite nanoparticles as multifunctional crosslinkers in PAAm ferrohydrogels. Macromolecules 2011, 44, 2990–2999.
  45. Ghadban, A.; Ahmed, A.S.; Ping, Y.; Ramos, R.; Arfin, N.; Cantaert, B.; Ramanujan, R.V.; Miserez, A. Bioinspired pH and magnetic responsive catechol-functionalized chitosan hydrogels with tunable elastic properties. Chem. Commun. 2016, 52, 697–700.
  46. Liao, J.; Huang, H. Review on magnetic natural polymer constructed hydrogels as vehicles for drug delivery. Biomacromolecules 2020, 21, 2574–2594.
  47. Barbucci, R.; Pasqui, D.; Giani, G.; De Cagna, M.; Fini, M.; Giardino, R.; Atrei, A. A novel strategy for engineering hydrogels with ferromagnetic nanoparticles as crosslinkers of the polymer chains. Potential applications as a targeted drug delivery system. Soft Matter 2011, 7, 5558–5565.
  48. Roeder, L.; Reckenthaler, M.; Belkoura, L.; Roitsch, S.; Strey, R.; Schmidt, A. Covalent ferrohydrogels based on elongated particulate crosslinkers. Macromolecules 2014, 47, 7200–7207.
  49. Mañas-Torres, M.C.; Gila-Vilchez, C.; Vazquez-Perez, F.J.; Kuzhir, P.; Momier, D.; Scimeca, J.-C.; Borderie, A.; Goracci, M.; Burel-Vandenbos, F.; Blanco-Elices, C. Injectable Magnetic-Responsive Short-Peptide Supramolecular Hydrogels: Ex Vivo and In Vivo Evaluation. ACS Appl. Mater. Interfaces 2021, 13, 49692–49704.
  50. Xie, W.; Gao, Q.; Guo, Z.; Wang, D.; Gao, F.; Wang, X.; Wei, Y.; Zhao, L. Injectable and self-healing thermosensitive magnetic hydrogel for asynchronous control release of doxorubicin and docetaxel to treat triple-negative breast cancer. ACS Appl. Mater. Interfaces 2017, 9, 33660–33673.
  51. Sun, S.; Mak, A.F. The dynamical response of a hydrogel fiber to electrochemical stimulation. J. Polym. Sci. Part B Polym. Phys. 2001, 39, 236–246.
  52. Hirai, T.; Nemoto, H.; Hirai, M.; Hayashi, S. Electrostriction of highly swollen polymer gel: Possible application for gel actuator. J. Appl. Polym. Sci. 1994, 53, 79–84.
  53. Kim, S.Y.; Lee, Y.M. Drug release behavior of electrical responsive poly (vinyl alcohol)/poly (acrylic acid) IPN hydrogels under an electric stimulus. J. Appl. Polym. Sci. 1999, 74, 1752–1761.
  54. Guo, B.; Finne-Wistrand, A.; Albertsson, A.-C. Degradable and electroactive hydrogels with tunable electrical conductivity and swelling behavior. Chem. Mater. 2011, 23, 1254–1262.
  55. Shiga, T.; Hirose, Y.; Okada, A.; Kurauchi, T. Bending of poly (vinyl alcohol)–poly (sodium acrylate) composite hydrogel in electric fields. J. Appl. Polym. Sci. 1992, 44, 249–253.
  56. Wanasingha, N.; Dorishetty, P.; Dutta, N.K.; Choudhury, N.R. Polyelectrolyte gels: Fundamentals, fabrication and applications. Gels 2021, 7, 148.
  57. Hirai, T.; Nemoto, H.; Suzuki, T.; Hayashi, S.; Hirai, M. Actuation of poly (vinyl alcohol) gel by electric field. J. Intell. Mater. Syst. Struct. 1993, 4, 277–279.
  58. Gao, Y.; Xu, S.; Wu, R.; Wang, J.; Wei, J. Preparation and characteristic of electric stimuli responsive hydrogel composed of polyvinyl alcohol/poly (sodium maleate-co-sodium acrylate). J. Appl. Polym. Sci. 2008, 107, 391–395.
  59. Li, L.; Hsieh, Y.-L. Ultra-fine polyelectrolyte hydrogel fibres from poly (acrylic acid)/poly (vinyl alcohol). Nanotechnology 2005, 16, 2852.
  60. Jin, S.; Gu, J.; Shi, Y.; Shao, K.; Yu, X.; Yue, G. Preparation and electrical sensitive behavior of poly (N-vinylpyrrolidone-co-acrylic acid) hydrogel with flexible chain nature. Eur. Polym. J. 2013, 49, 1871–1880.
  61. Yao, L.; Krause, S. Electromechanical responses of strong acid polymer gels in DC electric fields. Macromolecules 2003, 36, 2055–2065.
  62. Tang, Y.; Zhang, X.; Li, X.; Ma, C.; Chu, X.; Wang, L.; Xu, W. A review on recent advances of Protein-Polymer hydrogels. Eur. Polym. J. 2022, 162, 110881.
  63. Liu, J.; Ge, X.; Liu, L.; Xu, W.; Shao, R. Challenges and opportunities of silk protein hydrogels in biomedical applications. Mater. Adv. 2022, 3, 2291–2308.
  64. Zhang, Y.; Dong, L.; Liu, L.; Wu, Z.; Pan, D.; Liu, L. Recent Advances of Stimuli-Responsive Polysaccharide Hydrogels in Delivery Systems: A Review. J. Agric. Food Chem. 2022, 70, 6300–6316.
  65. Franco García, M.L.; Valle Mendoza, L.J.d.; Puiggalí Bellalta, J. Smart systems related to polypeptide sequences. AIMS Mater. Sci. 2016, 3, 289–323.
  66. Dorishetty, P.; Dutta, N.K.; Choudhury, N.R. Bioprintable tough hydrogels for tissue engineering applications. Adv. Colloid Interface Sci. 2020, 281, 102163.
  67. Athukorala, S.S.; Tran, T.S.; Balu, R.; Truong, V.K.; Chapman, J.; Dutta, N.K.; Roy Choudhury, N. 3D printable electrically conductive hydrogel scaffolds for biomedical applications: A review. Polymers 2021, 13, 474.
  68. Dorishetty, P.; Balu, R.; Athukoralalage, S.S.; Greaves, T.L.; Mata, J.; De Campo, L.; Saha, N.; Zannettino, A.C.; Dutta, N.K.; Choudhury, N.R. Tunable biomimetic hydrogels from silk fibroin and nanocellulose. ACS Sustain. Chem. Eng. 2020, 8, 2375–2389.
  69. Rahimi, N.; Molin, D.G.; Cleij, T.J.; van Zandvoort, M.A.; Post, M.J. Electrosensitive polyacrylic acid/fibrin hydrogel facilitates cell seeding and alignment. Biomacromolecules 2012, 13, 1448–1457.
  70. Sarmad, S.; Yenici, G.; Gürkan, K.; Keçeli, G.; Gürdağ, G. Electric field responsive chitosan–poly (N, N-dimethyl acrylamide) semi-IPN gel films and their dielectric, thermal and swelling characterization. Smart Mater. Struct. 2013, 22, 055010.
  71. Kim, S.J.; Yoon, S.G.; Lee, Y.H.; Kim, S.I. Bending behavior of hydrogels composed of poly (methacrylic acid) and alginate by electrical stimulus. Polym. Int. 2004, 53, 1456–1460.
  72. Wu, Y.; Wu, S.; Tian, X.; Wang, X.; Wu, W.; Zou, G.; Zhang, Q. Photoinduced reversible gel–sol transitions of dicholesterol-linked azobenzene derivatives through breaking and reforming of van der Waals interactions. Soft Matter 2011, 7, 716–721.
  73. Kloxin, A.M.; Kasko, A.M.; Salinas, C.N.; Anseth, K.S. Photodegradable hydrogels for dynamic tuning of physical and chemical properties. Science 2009, 324, 59–63.
  74. Deng, L.; Xu, Y.; Sun, C.; Yun, B.; Sun, Q.; Zhao, C.; Li, Z. Functionalization of small black phosphorus nanoparticles for targeted imaging and photothermal therapy of cancer. Sci. Bull. 2018, 63, 917–924.
  75. Fujigaya, T.; Morimoto, T.; Niidome, Y.; Nakashima, N. NIR Laser-Driven Reversible Volume Phase Transition of Single-Walled Carbon Nanotube/Poly (N-isopropylacrylamide) Composite Gels. Adv. Mater. 2008, 20, 3610–3614.
  76. Sershen, S.R.; Mensing, G.A.; Ng, M.; Halas, N.J.; Beebe, D.J.; West, J.L. Independent optical control of microfluidic valves formed from optomechanically responsive nanocomposite hydrogels. Adv. Mater. 2005, 17, 1366–1368.
  77. Yang, M.; Yuan, Z.; Liu, J.; Fang, Z.; Fang, L.; Yu, D.; Li, Q. Photoresponsive Actuators Built from Carbon-Based Soft Materials. Adv. Opt. Mater. 2019, 7, 1900069.
  78. Shiotani, A.; Mori, T.; Niidome, T.; Niidome, Y.; Katayama, Y. Stable incorporation of gold nanorods into N-isopropylacrylamide hydrogels and their rapid shrinkage induced by near-infrared laser irradiation. Langmuir 2007, 23, 4012–4018.
  79. Miyako, E.; Nagata, H.; Hirano, K.; Hirotsu, T. Photodynamic thermoresponsive nanocarbon–polymer gel hybrids. Small 2008, 4, 1711–1715.
  80. Qian, X.; Zhao, Y.; Alsaid, Y.; Wang, X.; Hua, M.; Galy, T.; Gopalakrishna, H.; Yang, Y.; Cui, J.; Liu, N. Artificial phototropism for omnidirectional tracking and harvesting of light. Nat. Nanotechnol. 2019, 14, 1048–1055.
  81. Gupta, P.; Vermani, K.; Garg, S. Hydrogels: From controlled release to pH-responsive drug delivery. Drug Discov. Today 2002, 7, 569–579.
  82. Schmaljohann, D. Thermo-and pH-responsive polymers in drug delivery. Adv. Drug Deliv. Rev. 2006, 58, 1655–1670.
  83. Brannon-Peppas, L.; Peppas, N.A. Solute and penetrant diffusion in swellable polymers. IX. The mechanisms of drug release from pH-sensitive swelling-controlled systems. J. Control. Release 1989, 8, 267–274.
  84. De, S.K.; Aluru, N.; Johnson, B.; Crone, W.; Beebe, D.J.; Moore, J. Equilibrium swelling and kinetics of pH-responsive hydrogels: Models, experiments, and simulations. J. Microelectromech. Syst. 2002, 11, 544–555.
  85. Huang, Y.; Yu, H.; Xiao, C. pH-sensitive cationic guar gum/poly (acrylic acid) polyelectrolyte hydrogels: Swelling and in vitro drug release. Carbohydr. Polym. 2007, 69, 774–783.
  86. Kamei, N.; Morishita, M.; Chiba, H.; Kavimandan, N.J.; Peppas, N.A.; Takayama, K. Complexation hydrogels for intestinal delivery of interferon β and calcitonin. J. Control. Release 2009, 134, 98–102.
  87. Khan, H.; Chaudhary, J.P.; Meena, R. Anionic carboxymethylagarose-based pH-responsive smart superabsorbent hydrogels for controlled release of anticancer drug. Int. J. Biol. Macromol. 2019, 124, 1220–1229.
  88. Zhang, J.; Chu, L.-Y.; Li, Y.-K.; Lee, Y.M. Dual thermo-and pH-sensitive poly (N-isopropylacrylamide-co-acrylic acid) hydrogels with rapid response behaviors. Polymer 2007, 48, 1718–1728.
  89. Turan, E.; Caykara, T. Swelling and network parameters of pH-sensitive poly (acrylamide-co-acrylic acid) hydrogels. J. Appl. Polym. Sci. 2007, 106, 2000–2007.
  90. Yanfeng, C.; Min, Y. Swelling kinetics and stimuli-responsiveness of poly (DMAEMA) hydrogels prepared by UV-irradiation. Radiat. Phys. Chem. 2001, 61, 65–68.
  91. Wu, W.; Liu, J.; Cao, S.; Tan, H.; Li, J.; Xu, F.; Zhang, X. Drug release behaviors of a pH sensitive semi-interpenetrating polymer network hydrogel composed of poly (vinyl alcohol) and star poly . Int. J. Pharm. 2011, 416, 104–109.
  92. Xu, F.-J.; Kang, E.-T.; Neoh, K.-G. pH-and temperature-responsive hydrogels from crosslinked triblock copolymers prepared via consecutive atom transfer radical polymerizations. Biomaterials 2006, 27, 2787–2797.
  93. Abd El-Ghaffar, M.; Hashem, M.; El-Awady, M.; Rabie, A. pH-sensitive sodium alginate hydrogels for riboflavin controlled release. Carbohydr. Polym. 2012, 89, 667–675.
  94. Yoon, S.; Chen, B. Elastomeric and pH-responsive hydrogels based on direct crosslinking of the poly (glycerol sebacate) pre-polymer and gelatin. Polym. Chem. 2018, 9, 3727–3740.
  95. Che, Y.; Li, D.; Liu, Y.; Ma, Q.; Tan, Y.; Yue, Q.; Meng, F. Physically crosslinked pH-responsive chitosan-based hydrogels with enhanced mechanical performance for controlled drug delivery. RSC Adv. 2016, 6, 106035–106045.
  96. Raja, S.; Thiruselvi, T.; Mandal, A.B.; Gnanamani, A. pH and redox sensitive albumin hydrogel: A self-derived biomaterial. Sci. Rep. 2015, 5, 15977.
  97. Balu, R.; Reeder, S.; Knott, R.; Mata, J.; de Campo, L.; Dutta, N.K.; Choudhury, N.R. Tough photocrosslinked silk fibroin/graphene oxide nanocomposite hydrogels. Langmuir 2018, 34, 9238–9251.
  98. Dorishetty, P.; Balu, R.; Gelmi, A.; Mata, J.P.; Dutta, N.K.; Choudhury, N.R. 3D printable soy/silk hybrid hydrogels for tissue engineering applications. Biomacromolecules 2021, 22, 3668–3678.
  99. Bashari, A.; Rouhani Shirvan, A.; Shakeri, M. Cellulose-based hydrogels for personal care products. Polym. Adv. Technol. 2018, 29, 2853–2867.
  100. Cipriano, B.H.; Banik, S.J.; Sharma, R.; Rumore, D.; Hwang, W.; Briber, R.M.; Raghavan, S.R. Superabsorbent hydrogels that are robust and highly stretchable. Macromolecules 2014, 47, 4445–4452.
  101. Sharma, K.; Kumar, V.; Chaudhary, B.; Kaith, B.; Kalia, S.; Swart, H. Application of biodegradable superabsorbent hydrogel composite based on Gum ghatti-co-poly (acrylic acid-aniline) for controlled drug delivery. Polym. Degrad. Stab. 2016, 124, 101–111.
  102. Sadeghi, M.; Soleimani, F. Synthesis and characterization of superabsorbent hydrogels for oral drug delivery systems. Int. J. Chem. Eng. Appl. 2011, 2, 314–316.
  103. Karadağ, E.; Saraydın, D.; Güven, O. Radiation induced superabsorbent hydrogels. Acrylamide/itaconic acid copolymers. Macromol. Mater. Eng. 2001, 286, 34–42.
  104. Zhu, Z.-Q.; Sun, H.-X.; Qin, X.-J.; Jiang, L.; Pei, C.-J.; Wang, L.; Zeng, Y.-Q.; Wen, S.-H.; La, P.-Q.; Li, A. Preparation of poly (acrylic acid)–graphite oxide superabsorbent nanocomposites. J. Mater. Chem. 2012, 22, 4811–4817.
  105. Liu, Z.; Rempel, G. Preparation of superabsorbent polymers by crosslinking acrylic acid and acrylamide copolymers. J. Appl. Polym. Sci. 1997, 64, 1345–1353.
  106. Ma, J.; Li, X.; Bao, Y. Advances in cellulose-based superabsorbent hydrogels. RSC Adv. 2015, 5, 59745–59757.
  107. Athukoralalage, S.S.; Balu, R.; Dutta, N.K.; Roy Choudhury, N. 3D bioprinted nanocellulose-based hydrogels for tissue engineering applications: A brief review. Polymers 2019, 11, 898.
  108. Cuadri, A.; Bengoechea, C.; Romero, A.; Guerrero, A. A natural-based polymeric hydrogel based on functionalized soy protein. Eur. Polym. J. 2016, 85, 164–174.
  109. Dorishetty, P.; Balu, R.; Sreekumar, A.; de Campo, L.; Mata, J.P.; Choudhury, N.R.; Dutta, N.K. Robust and tunable hybrid hydrogels from photo-crosslinked soy protein isolate and regenerated silk fibroin. ACS Sustain. Chem. Eng. 2019, 7, 9257–9271.
  110. Zain, G.; Nada, A.A.; El-Sheikh, M.A.; Attaby, F.A.; Waly, A.I. Superabsorbent hydrogel based on sulfonated-starch for improving water and saline absorbency. Int. J. Biol. Macromol. 2018, 115, 61–68.
  111. Warkar, S.G.; Kumar, A. Synthesis and assessment of carboxymethyl tamarind kernel gum based novel superabsorbent hydrogels for agricultural applications. Polymer 2019, 182, 121823.
  112. Yoshimura, T.; Uchikoshi, I.; Yoshiura, Y.; Fujioka, R. Synthesis and characterization of novel biodegradable superabsorbent hydrogels based on chitin and succinic anhydride. Carbohydr. Polym. 2005, 61, 322–326.
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