Dual-network Hydrogel Research Articles

3D printable and stretchable PVA‐PAAm dual network hydrogel with conductivities for wearable sensors

AbstractConductive hydrogel has broad potential applications in wearable sensors and flexible electronic devices. However, due to the complicated and restrictive mold‐casting process, the manufacture of hydrogel‐based sensors is still facing great challenges. In this paper, we adopt direct inkjet printing (DIW) technology to fabricate three‐dimensional structures of chemically and physically cross‐linked hydrogels by integrating fumed silica as a rheological modifier into crosslinked poly(vinyl alcohol)/poly(acrylamide) (PVA/PAAm) network. Fumed silica not only enables hydrogels with excellent rheological properties, but also provides more hydrogen bond crosslinking sites, further improving mechanical properties. Meanwhile, calcium chloride (CaCl2) is supplemented to construct conductive channels in the hydrogel, which powers the hydrogel with good conductivity and strain sensitivity. The sensor assembled from 3D printed hydrogel shows cycle stability and accurate recognition ability in detecting mechanical deformation and various human movements (for example knee bending and frown). This work extends the application of 3D printing hydrogel in the field of wearable devices.

Constructing nickel-based bifunctional oxygen catalyst and dual network hydrogel electrolyte for high-performance, compressible and rechargeable zinc-air batteries

Wearable Zn-air battery (ZAB) delivers great potential for the next-generation wearable electronic devices. It requires the ZAB accommodating not only the high-power, high efficiency but also the mechanical stability even subjected to largely compression force. However, it remains a great challenge to obtain the highly efficient O2 catalyst as well as the compressible electrolyte. Herein, we constructed a high-performed and compressible ZAB based on the Ni-based bifunctional O2 catalyst and designed a dual network hydrogel electrolyte for outstanding electrochemical and mechanical performance. The as-obtained compressible ZAB based on the Ni-NC catalyst and the hydrogel electrolyte could exhibited an open-circuit voltage of 1.44 V, a peak power density of 87.7 mW cm−2, and an energy efficiency of ∼58%. When the ZAB being compressed up to 50%, the maximum power density could retain at 69.3%. This research could provide new insights for applying the Ni-NC catalyst and the dual network hydrogel to obtain high-performance wearable ZAB.

A Dual-network Nerve Adhesive with Enhanced Adhesion Strength Promotes Transected Peripheral Nerve Repair.

Peripheral nerve transection has a high prevalence and results in functional loss of affected limbs. The current clinical treatment using suture anastomosis significantly limits nerve recovery due to severe inflammation, secondary damage, and fibrosis. Fibrin glue, a commercial nerve adhesive as an alternative, avoids secondary damage but suffers from poor adhesion strength. To address their limitations, a highly efficacious nerve adhesive based on dual-crosslinking of dopamine-isothiocyanate modified hyaluronic acid and decellularized nerve matrix is reported in this paper. This dual-network nerve adhesive (DNNA) shows controllable gelation behaviors feasible for surgical applications, robust adhesion strength, and promoted axonal outgrowth in vitro. The in vivo therapeutic efficacy is tested using a rat-based sciatic nerve transection model. The DNNA decreases fibrosis and accelerates axon/myelin debris clearance at 10 days post-surgery, compared to suture and commercial fibrin glue treatments. At 10 weeks post-surgery, the strong adhesion and bioactivity allow DNNA to significantly decrease intraneural inflammation and fibrosis, enhance axon connection and remyelination, aid motor and sensory function recovery, as well as improve muscle contraction, compared to suture and fibrin treatments. Overall, this dual-network hydrogel with robust adhesion provides a rapid and highly efficacious nerve transection treatment to facilitate nerve repair and neuromuscular function recovery.

Highly Efficient and Salt-Rejecting Poly(vinyl alcohol) Hydrogels with Excellent Mechanical Strength for Solar Desalination.

Interfacial solar steam generation (ISSG)-based solar desalination has recently emerged as a promising solution to tackle the global issue of fresh water scarcity. However, the energy-intensive process of conventional vapor generation techniques limits its practical applications. Hydrogels with three-dimensional (3D) structures have been reported to alleviate this energy demand, but their applications in sustainable solar desalination are hindered by their poor mechanical stability. Herein, we propose a 3D poly(vinyl alcohol) (PVA)-based hydrogel with excellent mechanical strength for effective solar desalination. The dual polymer network hydrogel (PVA-agar) incorporated with multi-walled carbon nanotubes (MWCNTs) achieved a noticeable evaporation rate of 3.1 kg m-2 h-1 under 1 sun irradiation, owing to its broadband light absorption, intrinsic water channels, and microporous structure that help reduce the latent heat of vaporization. More importantly, the application of kosmotropic ammonium sulfate ions was found to greatly improve the mechanical strength of the hydrogels using a facile Hofmeister-assisted soaking method. Finally, the PVA-agar-MWCNT hydrogel was able to desalinate seawater efficiently (2.5 kg m-2 h-1) with self-cleaning capability of salt crystals. The salinity level of the desalinated water was also comparable to drinking clean water. The present results would pave the way for fabricating mechanically strong, hydrophilic, and highly efficient hydrogels for effective and sustainable solar desalination.

Anti-freezing dual-network hydrogels with high-strength, self-adhesive and strain-sensitive for flexible sensors

Hydrogels as flexible sensor have attracted significant attention due to its conductivity, stretchability and flexibility. However, it is still a great challenge to prepare hydrogels that simultaneously possess high strength, anti-fatigue, self-adhesion, and anti-freezing. Herein, a multifunctional dual-network hydrogel was prepared by in situ polymerization of acrylic monomer in chitosan chains, and coordinated with aluminum chloride and glycerol. Based on chain entanglement, hydrogen bonding and coordination interactions, this dual-network hydrogel exhibited excellent mechanical properties, good fatigue resistance, and excellent adhesion performance. It can be used as a strain sensor for its stable conductivity and high sensitivity, which could monitor both large human motions and subtle motions. Due to the presence of glycerol, the hydrogel showed outstanding freezing resistance and still kept flexible and conductive even at low temperatures (−20 °C). This hydrogel can be applied as a flexible wearable sensor for monitoring human motion in extreme low-temperature condition.

Natural Dual-Crosslinking Bioadhesive Hydrogel for Corneal Regeneration in Large-Size Defects.

Corneal injectable hydrogels represent a promising alternative to alleviate donor shortage and simplify traditional surgeries. However, most hydrogels focus on repairing focal corneal defects (≤3.5mm) and leave many clinical requirements unmet. Herein, a novel ion-activated bioadhesive hydrogel (IonBAH) is designed and its long-term performance of repairing large corneal defects (6mm) is evaluated in rabbits for 6 months. The IonBAH is a dual-network hydrogel composed of natural corneal extracellular matrix and peptide-modified alginate, which enables its desirable transparency and biocompatibility, tunable mechanics, and robust adhesion. Moreover, the IonBAH maintains the secretory phenotype of quiescent keratocytes, while preventing their myofibroblastic differentiation in vitro. Upon application in situ, it rapidly seals the 6mm corneal defect and forms normal curvature through the coverage of a contact lens impregnated with calcium ions. During the 6 months follow-up, the IonBAH promotes rapid regeneration of corneal epithelium, stroma, and nerves with restored transparency, equivalent to the outcome of donor corneal transplantation. In addition, the suitability of IonBAH as an adhesive and patch for various clinical requirements are also evaluated with a pleasing outcome. Collectively, IonBAH may provide a clinically applicable scaffold for corneal surgeries, especially in large defect repair.

Mussel-induced nano-silver antibacterial, self-healing, self-adhesive, anti-freezing, and moisturizing dual-network organohydrogel based on SA-PBA/PVA/CNTs as flexible wearable strain sensors

Hydrogel-based flexible wearable sensors have appeared to great interest owing to their great potential in medical monitoring, electronic skin, and artificial intelligence. Nevertheless, it is still a considerable challenge to fabricate multifunctional hydrogel sensors with good flexibility, self-adhesion, self-healing, antibacterial, and excellent sensing properties at the same time. In this work, a dual-network (DN) conductive hydrogel was prepared by modified sodium alginate/polyvinyl alcohol/acacia mangium tannin/carbon nanotubes (SA-PBA/PVA/AMT/CNTs), which exhibited high stretchability (717%), biocompatibility, wide adhesion ability, efficient self-healing performance (self-healing efficiency reaches 99.67%), good antibacterial property and considerable sensitivity (in the strain range of 250–525%, gauge factor reaches 8.89). When the DN conductive hydrogel was constructed as a flexible strain sensor, it can be used to monitor various large and subtle human motions. To further endow the DN hydrogel with environmental tolerance, glycerol was introduced into the hydrogel to obtain an anti-freezing and water-retaining organohydrogel. Interestingly, the obtained organohydrogel permanently maintained good adhesion, self-healing, antibacterial, sensitivity, and sensing properties at low temperatures (−24 °C) or room temperature. In summary, the present work provides a new strategy for the preparation of multifunctional DN organohydrogel as wearable electronics.

Design of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate-polyacrylamide dual network hydrogel for long-term stable, highly efficient solar steam generation

Photothermal materials have attracted significant interests for interfacial solar steam generation towards desalination or sewage purification. However, despite recent encouraging progress, the development of long-term stable photothermal materials with high overall performance is still one of the major hurdles to realize scalable practical usage. Herein, we develop a dual network hydrogel of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and polyacrylamide (PAAm) for interfacial solar steam generation via one-step radical polymerization and chemical cross-linking of acrylamide within viscous PEDOT:PSS nanofibril dispersion. As-obtained PEDOT:PSS-PAAm hydrogel exhibits a unique combination of advantageous evaporation performances including excellent sunlight absorption (∼99.8%), fast steam generation rate (2.15 kg m-2 h-1), and high energy efficiency (∼97.2%), comparable to the state-of-the-art photothermal materials. Furthermore, the PEDOT:PSS-PAAm hydrogel also displays fascinating mechanical properties like softness (Young’s modulus: 38 ∼ 86 kPa), stretchability (fracture strain: >80%), and nice mechanical stability against varying deformations, guaranteeing its potential usage in harsh practical application environment. Toward real water purification applications, such a hydrogel is demonstrated to possess excellent long-term stability with an average energy efficiency of 94.8% and anti-salt-fouling properties against 30-day continuous outdoor exposure, superior to most previously reported photothermal materials. We further demonstrate PEDOT:PSS-PAAm hydrogel-integrated solar steam generator for practical desalination and sewage purification, and the generated water can reach the WHO drinking water standards for metal cations/organic pollutants.

Super stretchability, strong adhesion, flexible sensor based on Fe3+ dynamic coordination sodium alginate/polyacrylamide dual-network hydrogel

Bionic hydrogel sensors have been known as promising alternatives to biomimetic skins. Here, a bionic hydrogel sensor based on sodium alginate (Alg), polyacrylamide (PAAM) and Fe3+ have been fabricated by a simple one-pot method, shows super stretchability, excellent adhesion and conductivity. The Fe3+/Alg-PAAM hydrogel was endowed with a dynamic coordination dual-network structure based on controllable Fe3+ penetration and free radical polymerization dual effect, which was equipped with the synergistic properties of high storage modulus (2200 KPa), super stretchability (1800%) and strong adhesion to various substrates (glass adhesion with 61.8 KPa). Moreover, due to abundant free ions, the Fe3+/Alg-PAAM hydrogel displays good conductive behavior, and further shows excellent sensing behavior and strain sensitivity as a skin sensor to monitor human movement. This work enriches the design and preparation strategies of flexible hydrogels to promote the application of Alg-based materials for the wearable electronic devices and intelligent monitoring systems.

Dual-network self-healing hydrogels composed of graphene oxide@nanocellulose and poly(AAm-co-AAc)

A nature-inspired strategy is developed to build dual-network hydrogels made up of rigid graphene oxide-functionalized nanocellulose (GO@NC) network and flexible poly[acrylamide-co-(acrylic acid)] (poly(AAm-co-AAc)) network. A pre-stretching method is used to form a muscle-shape anisotropic architecture. The penetration of poly(AAm-co-AAc) flexible network relieves the stiffness of NC network, thus improving the average elongation at break from 86.2 % to 748.0 %. Compared with the poly(AAm-co-AAc), the average rupture tensile strength rises remarkably by 228.6 %. The dual-crosslinked strategy endows the GO@NC-poly(AAm-co-AAc) hydrogels with a fast, stable and repeatable self-healing ability, which can achieve 85.0 % of healing efficiency after only 600 s of self-healing and maintain 76.2 % of initial strength after 10 cycles of breaking–self-healing. The superb self-healing ability is similar to the muscle function. For potential applications, the hydrogels can achieve real-time, stable, and long-term sensing as smart wearable strain sensors (high gauge factor: 5.13), and can effectively purify Sudan IV wastewater as green recyclable adsorbents.

An injectable, self-healing, 3D printable, double network co-enzymatically crosslinked hydrogel using marine poly- and oligo-saccharides for wound healing application

In this study, we designed dual network hydrogels with antioxidant and antibacterial activities using marine poly- and oligosaccharides with skin wound healing potential. The synergy between dual enzymatic co-crosslinking based on glucose oxidize (GOx)/horseradish peroxidase (HRP) and electrostatic interaction between positively charged chitooligosaccharides (COS) and phenolated chitosan with negatively charged phenolated alginate formed a hydrogel. The Gel-COS hydrogels exhibited toughness, self-healing, moldability, injectability, and 3D printability. Investigation of the physicochemical properties of the hydrogels exhibited a swelling ratio (< 50%) and in vitro biodegradation after 9 days. Furthermore, the hydrogels exhibited antioxidant properties and antibacterial activity against E. coli and S. aureus. The hydrogels were not cytotoxic and enhanced the migration of 3D cell encapsulated 3T3-L1 fibroblasts, blood vessel formation, as well as in vivo wound healing in a rat model. The Gel-COS hydrogel can be considered a promising skin wound dressing material.

Charge and receptor functional injectable hydrogels as cytokine-releasing reservoirs for wound healing

Collecting and utilizing various cytokines released by trauma and implantable materials for stimulating the body in producing a robust immune-inflammatory response would be a promising method. Therefore, an injectable “cytokine reservoir” hydrogel for cytokine management during tissue repair was developed by combining a dual network hydrogel of oxidized glucomannan aldehyde (KGM-CHO) and levodopa-grafted ε-polylysine (EPL-DOPA). The “cytokine reservoir” hydrogel actively recruited macrophages through electrostatic forces and regulated macrophages by mimicking “receptor-ligand” interactions to alter cytokine production patterns. Meanwhile, the dual network hydrogels recruited and stored cytokines by “charge” force then released them according to the degradation of hydrogels, leading to the change of cytokine release pattern. In conclusion, this study provided a unique insight in designing the cytokine management-based tissue engineering strategies for tissue repair.

Highly Sensitive and Robust Polysaccharide-Based Composite Hydrogel Sensor Integrated with Underwater Repeatable Self-Adhesion and Rapid Self-Healing for Human Motion Detection.

Tough, biocompatible, and conductive hydrogel-based strain sensors are attractive in the fields of human motion detection and wearable electronics, whereas it is still a great challenge to simultaneously integrate underwater adhesion and self-healing properties into one hydrogel sensor. Here, a highly stretchable, sensitive, and multifunctional polysaccharide-based dual-network hydrogel sensor was constructed using dialdehyde carboxymethyl cellulose (DCMC), chitosan (CS), poly(acrylic acid) (PAA), and aluminum ions (Al3+). The obtained DCMC/CS/PAA (DCP) composite hydrogels exhibit robust mechanical strength and good adhesive and self-healing properties, due to the reversible dynamic chemical bonds and physical interactions such as Schiff base bonds and metal coordination. The conductivity of hydrogel is 2.6 S/m, and the sensitivity (gauge factor (GF)) is up to 15.56. Notably, the DCP hydrogel shows excellent underwater repeatable adhesion to animal tissues and good self-healing properties in water (self-healing rate > 90%, self-healing time < 10 min). The DCP hydrogel strain sensor can sensitively monitor human motion including finger bending, smiling, and wrist pulse, and it can steadily detect human movement underwater. This work is expected to provide a new strategy for the design of high-performance intelligent sensors, particularly for applications in wet and underwater environments.

PVA/gelatin/β-CD-based rapid self-healing supramolecular dual-network conductive hydrogel as bidirectional strain sensor

Hydrogel-based flexible sensors have exhibited great application prospect in the fields of e-skin, movement monitoring and human-computer interaction. Nevertheless, it is still a difficult problem to construct the biomass-based hydrogel sensors with considerable mechanical property, biocompatibility, self-healing property, sensitivity, self-adhesion and fatigue resistance. Herein, a gelatin-based dual-network (DN) hydrogel sensor with multiple dynamic crosslinking was successfully fabricated, in which the dynamic Schiff base bonds between gelatin and an aldehyde-containing supramolecular crosslinker (PCD-Fc-CHO) formed by the host-guest complexing of β-cyclodextrin (β-CD) to ferrocene (Fc) were used to construct the first network of the hydrogel, while the reversible borate ester bonds of PVA with borax were utilized to establish the second network. Meantime, carbon nanotubes (CNTs) were added to endow the gelatin-based DN hydrogel with good conductivity and improved mechanical property. The prepared gelatin-based DN hydrogel possesses favorable ductility (1200%), biocompatibility, double self-healing (HE = 96%), high sensitivity (GF = 6.4), self-adhesion (repeatable adhesion), dual stimuli-responsiveness (pH and oxidation), plasticity and fatigue resistance. The DN hydrogel-based strain sensor can not only monitor various human body (e.g. fingers, knees, speech, etc.) movements and vital signs (pulse), but also monitor in vitro the breathing movements of pig lungs. Interestingly, the self-healed gelatin-based DN hydrogel sensor can also be reused, and its monitoring ability is basically the same as the original hydrogel. This work puts forward a new strategy for the construction of multiple dynamically cross-linked biomass-based self-healing hydrogels as multifunctional wearable flexible sensors.

Thiolated hyaluronic acid/silk fibroin dual-network hydrogel incorporated with bioglass nanoparticles for wound healing

Thiolated hyaluronic acid(THA) conjugates were synthesized and the selected THA was combined with silk fibroin(SF) and bioactive glass nanoparticles to build a novel type of composite hydrogel with dual-network structure. The optimally achieved gels showed greatly enhanced strength and stiffness compared to the gels built from either THA or SF while having well-defined elasticity and injectability. They were able to sustainably release Si ions in approximately linear manners for around three weeks. In vitro cell culture revealed that they supported the in-growth and proliferation of seeded cells, and showed the ability to markedly stimulate the migration of both fibroblasts and human umbilical vein endothelial cells. In vivo results based on the 10 mm mouse full-thickness skin defect demonstrated that they were able to fully restore the skin defects with formation of vascularized tissues and complete appendages during two weeks, suggesting their highly promising potency in use for wound healing.

Ultra-stretchable dual-network ionic hydrogel strain sensor with moistening and anti-freezing ability

Ionic hydrogel strain sensors are widely used in wearable electronic devices because of their excellent stretchability and responsiveness. However, ordinary ionic hydrogels are easy to dry during working under low temperatures, which severely limit their service life and application areas. Herein, we constructed a dual-network ionic conductive hydrogel based on the alginate/polyacrylamide dual-network hydrogel via solvent replacement treatment, which can be further applied as the wearable strain sensors. The solvent replacement process is by soaking the dual-network hydrogel in LiCl/CaCl2/glycerin/water solution, in which divalent cations Ca2+ ions cross-linking with the alginate chain to further toughen the dual-network, thus obtaining high stress of ~0.81 MPa and a high ionic conductivity (>19.4 mS/cm), and the mixed salt solution of glycerin/water provides excellent moisture for >30 days and frost resistance even under −80 °C ultralow temperature. Impressively, the resulting hydrogel sensor demonstrates excellent sensitivity and cyclic stability in detecting tensile deformation and human motion in a range of sizes. This work provides a feasible method for the construction of high-strength, moisturizing, antifreeze, and durable hydrogel sensors with high sensitivity and a wide range of detection capabilities, and provides a new idea for the application of electronic skin and intelligent wearable devices.

Multifunctional polysaccharide hydrogels for skin wound healing prepared by photoinitiator-free crosslinking

Photocrosslinked hydrogels show great potential as dressings for skin wound healing. However, most current hydrogels suffer from poor adhesion, toxic photoinitiators, and insufficient versatility. Therefore, developing novel hydrogel dressings with appropriate properties is of great importance to accelerate the wound healing process. In this study, we developed a polysaccharide-based dual-network hydrogel consisting of azide-functionalized carboxymethyl chitosan and o-nitrobenzyl-modified hyaluronic acid (CMC-AZ/HA-NB). The hydrogel showed excellent mechanical, tissue adhesion, and water retention properties. Controllable in situ photocrosslinking was carried out without photoinitiator, avoiding issues associated with the cytotoxicity of photoinitiators. An antibacterial agent-loaded hydrogel (CMC-AZ/HA-NB@D) showed enhanced antibacterial properties. In addition, the CMC-AZ/HA-NB@D hydrogel promoted collagen deposition and vascular formation, as well as reducing the expression of pro-inflammatory factors, thereby accelerating the wound healing process and improving skin regeneration. The present results highlight the promising potential of multifunctional photoinitiator-free polysaccharide hydrogels for application in wound dressings.

3D bioprintable methacrylated carrageenan/sodium alginate dual network hydrogel for vascular tissue engineering scaffolding

3D printing technology has significant advantages in the processing field of vascular tissue engineering. We have developed KCMA/SA hydrogels based on methacrylated carrageenan (KCMA) and sodium alginate (SA), which have low viscosity and shear thinning properties and can be used for 3D printing. The physicochemical double cross-linked network structure leads to good mechanical properties. The composite hydrogels maintain the liquid crystallinity of KC, which causes the HUVECs to align. The KCMA/SA gel filaments printed by the 3D extrusion printing system formed a connected microstructure. These characteristics all indicate the potential of KCMA/SAs in the field of tubular tissue regeneration.

Bio-fabricated nanocomposite hydrogel with ROS scavenging and local oxygenation accelerates diabetic wound healing.

Chronic wounds, especially diabetic wounds, involve abnormally long inflammatory periods due to their pathological microenvironment of high reactive oxygen species (ROS) levels and lack of blood vessels. Here, via a mild, simple and feasible fabrication approach, a sustained oxygenation system is proposed, consisting of MnO2 nanosheets and a dual-network hydrogel fabricated from natural biomaterials including silk fibroin (SF) and carboxymethyl cellulose (CMC). Compared with the initial value (61.09 kPa), the compression modulus of the dual-network hydrogel increased by 116.2% through the coordination of strong covalent bonds and sacrificial coordination bonds constructed by enzymatic crosslinking and UV-irradiation crosslinking; the intrinsic shear-thinning effect endows the dual-network hydrogel with satisfactory injectable properties to be customized as a predetermined shape to accommodate the irregular wounds of diabetes. The encapsulated MnO2 nanosheets can catalyze the excessive ROS into necessary O2in situ and, after co-incubating with the SF/CMC@MnO2 hydrogels, cells in oxidative stress show significantly lower ROS (3 times) and higher O2 (17 times) levels that are conductive to relieving oxidative stress, promoting angiogenesis and reducing inflammation in vivo. Meanwhile, these SF-based hydrogels can offset the overexpression of matrix metalloproteinases (MMPs) in diabetic wounds (more than 80%) and promote remodeling of the extracellular matrix. Eventually, wound healing rates >76% in 7 days and 100% in 14 days were achieved by the bio-fabricated nanocomposite hydrogel and are remarkably faster than the commercial dressing healing rates (<30% in 7 days and <80% in 14 days). These results indicate that this bio-fabricated hydrogel system with multiple and customizable functions has great promise in the personalized clinical care of chronic wounds.

Dual-network hydrogel based on ionic nano-reservoir for gastric perforation sealing

In recent years, remarkable progress has been made in the research of injectable hydrogel for internal tissue healing. However, the therapeutic outcome is usually limited when the hydrogel is used for the treatment of gastric perforation due to the high acidic gastric juice and violent deformation of the gastric wall. Regarding these challenges, we proposed an ionic nano-reservoir (INR)-based dual-network hydrogel, which has excellent adhesion and mechanical properties, and can be easily applied to the perforation site to block the perforation while promoting tissue repairing. The results showed that the first network made of polyacrylamide had cross-linked on the stomach tissue within 5 s under blue light, and enhanced the adhesion performance through mechanical interlock. The nano-hydroxyapatite acted as ionic INR, which can gradually release Ca2+ under acid environments to form the second network with sodium alginate and inhibit the swelling of hydrogel in gastric juice. Meanwhile, the adhesion was further enhanced through amide covalent bonds at the hydrogel-tissue interface with the presence of 1- ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS). The dual network hydrogels obtained by the INR strategy could be employed as a potential therapeutic option for gastric perforation and other similar biomedical prolems.