Cationic Guar Research Articles

Incorporating copper-based nanosheets into an injectable self-healing hydrogel enables superb repair of infected diabetic wound

Continuous bleeding, bacterial infection, oxidative stress, and vascular damage within a diabetic wound microenvironment necessitate the development of multifunctional dressings that match the complex physiological process of skin healing. Herein, copper–tannic acid (CuTA) nanosheets were first synthesized by chelating copper ions with tannic acid (TA). These nanosheets were subsequently integrated into an injectable self-healing hydrogel comprising methacrylic anhydride-modified gelatin (GelMA), cationic guar gum (CG), and borax. Through free-radical polymerization as well as hydrogen and borate ester bonds formation, we fabricated an acidic and highly reactive oxygen species (ROS)-responsive composite hydrogel named GGB-CT, which exhibited remarkable hemostasis and adhesion. With responsive decomposition of GGB-CT, the released CuTA efficiently scavenged excess ROS as well as effectively killed bacteria by inhibiting arginine synthesis, blocking the tricarboxylic acid cycle and inducing cuproptosis-like death in the tested microbes. In the later stages of wound healing, the composite hydrogel substantially promoted macrophage polarization and angiogenesis, thus accelerating the re-epithelialization of the wound area. Overall, this study proposes an innovative hydrogel for treating infected diabetic wounds and may inspire new thinking of high-performance hydrogels for biomedical applications.

Metallic-Polyphenolic Nanoparticles Reinforced Cationic Guar Gum Hydrogel for Effectively Treating Burn Wound.

The development of injectable hydrogel dressings which are long-term moisturizing, easy-to-apply, and effectively inhibiting infection and inflammatory is essential to promote burn wound repairing. Herein, an injectable hydrogel with moisturizing, antibacterial, and anti-inflammation abilities via multiple reversible interactions between cation guar gum (CG) and metallic-polyphenolic nanoparticles (PA-ZnII NPs) is developed. Specifically, PA-ZnII NPs is formed by synergistic complexation of protocatechualdehyde (PA) and zinc ion (Zn2+ ), provides CGPZ hydrogel with plentiful reversible interactions to inhibit the loss of moist. By interacting with PA-ZnII NPs, the CGPZ hydrogel can provide enhanced moisturization for more than 3 days. Moreover, the CGPZ hydrogel can maintain good adhesion for a period of time with injection and self-healing capabilities due to reversible interactions between CG and PA-ZnII NPs. In addition, CGPZ hydrogel exhibits outstanding broad spectrum antibacterial performance, as its killing efficiency against Escherichia coli and Staphylococcus aureus is all greater than 99.99%. Importantly, compared with commercial dressing, the CGPZ hydrogel can promote wound healing faster by inhibiting tissue damage from dysregulated inflammation and accelerating neovascularization. It is believed that the moisturizing CGPZ hydrogel with antibacterial and anti-inflammation performance can serve as a promising dressing for the effective treatment of burn wound.

Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel

Hydrogels are three-dimensional structures with specific features that render them useful for biomedical applications, such as tissue engineering scaffolds, drug delivery systems, and wound dressings. In recent years, there has been a significant increase in the search for improved mechanical properties of hydrogels derived from natural products to extend their applications in various fields, and there are different methods to obtain strengthened hydrogels. Cationic guar gum has physicochemical properties that allow it to interact with other polymers and generate hydrogels. This study aimed to develop an ultra-stretchable and self-healing hydrogel, evaluating the influence of adding PolyOX [poly(ethylene oxide)] on the mechanical properties and the interaction with cationic guar gum for potential tissue engineering applications. We found that variations in PolyOX concentrations and pH changes influenced the mechanical properties of cationic guar gum hydrogels. After optimization experiments, we obtained a novel hydrogel, which was semi-crystalline, highly stretchable, and with an extensibility area of approximately 400 cm2, representing a 33-fold increase compared to the hydrogel before being extended. Moreover, the hydrogel presented a recovery of 96.8% after the self-healing process and a viscosity of 153,347 ± 4,662 cP. Therefore, this novel hydrogel exhibited optimal mechanical and chemical properties and could be suitable for a broad range of applications in different fields, such as tissue engineering, drug delivery, or food storage.

Robust, ultrathin and flexible electromagnetic interference shielding paper designed with all-polysaccharide hydrogel and MXene

An effective strategy was demonstrated to design an electromagnetic interference (EMI) shielding paper via a facile surface treatment on paper. TEMPO-oxidized cellulose nanofibers (TOCN) were first integrated with Ti3C2Tx MXene, and subsequently cast onto a filter paper with cationic guar gum (CGG) in a sequential way. TOCN and CGG generated a self-assembling hydrogel and formed a MXene-containing hydrogel film on top of the filter paper. The hydrogel film enhanced the tensile strength (9.49 MPa) of composite paper, and resulted in a 17 % increase as compared to the control. The composite paper containing 80 mg MXene (namely, 2.07 mg·cm−2) showed a conductivity of 3843 S·m−1 and EMI shielding effectiveness (EMI SE) of 49.37 dB. Furthermore, the 2-layer assembled TC-M 80 hydrogel composite paper achieved an EMI SE of 73.99 dB. Importantly, this composite paper showed higher EMI SE and lower thickness than a lot of reported materials. The presence of TOCN and CGG also protected MXene against several solvents and the incorporation of polydimethylsiloxane (PDMS) further improved the durability of the composite paper. This work provides a novel and simple strategy to design robust, ultrathin and flexible EMI shielding materials, and it might also inspire other work in paper-based functional materials.

Three-dimensional dual-network magnetic conductive hydrogel for the highly sensitive electrochemical detection of ponceau 4R in foods

Synthetic pigment Ponceau 4 R is a commonly used additive in the process of various foods. Due to its potential toxicity to humans, realizing high sensitivity and rapid detection of Ponceau 4 R is extremely important. In this study, we synthesized a novel dual-network magnetic conductive hydrogel (MCHG) via a simple one-pot low temperature stirring method. In MCHG, cationic guar gum (CGG) and β-cyclodextrin (β-CD) formed a primary three-dimensional network cross-linked by N, N-methylene bisacrylamide. A second network was formed in MCHG by CGG, β-CD and magnetite@carboxylate-terminated carbon nanotubes (Fe3O4@COOH-MWCNTs) through hydrogen bonding and electrostatic interactions. Fe3O4@COOH-MWCNTs enhanced cross-linking in the MCHG hydrogel, whilst also boosting the equilibrium adsorption capacity of Ponceau 4 R (61.8 mg g−1), electrical conductivity and electrocatalytic performance. Application of MCHG to a glassy carbon electrode (GCE) created a highly sensitive electrochemical sensor for the detection of Ponceau 4 R. Under optimized testing conditions, the sensor offered a very wide linear range (0.01–200.0 μM) and a low limit of detection (1.8 nM) for Ponceau 4 R. When the sensor was applied to the detection of Ponceau 4 R in spiked honey and liqueur samples, excellent recoveries were achieved (88.2%–107.0%). Furthermore, analyses of commercial biscuit and candy samples using the MCHG/GCE sensor and a national standard ultraviolet spectrophotometry method afforded identical results. Results demonstrate that multifunctional hydrogels show great promise as signal amplification agents in electrochemical detection of target compounds in foods.

Guar gum series affect nanostructured lipid carriers via electrostatic assembly or steric hindrance: Improving their oral delivery for phytosterols

Surface modification of nanostructured lipid carriers (NLCs) can be an effective way to improve their oral delivery for active ingredients. In this study, four type of guar gum series modified NLCs for the delivery of phytosterols (PS) were constructed and the effects of the polysaccharides on their structure and physicochemical properties were studied. DLS and AFM results revealed that positively charged polysaccharides could bind to PS-NLCs through electrostatic attraction and made the complexes finally take positive charges, while negatively charged polysaccharides were more likely to fill in the gaps of NLC systems to achieve a balance between electrostatic repulsion and intermolecular forces. Although all four polysaccharides exhibited good storage stability and controlled release of PS in simulated intestinal digestion, PS-NLCs modified with partially hydrolyzed cationic guar gum (PHCG) at medium or high concentrations exhibited better gastric stability, mucoadhesion, and cellular uptake, which had considerable significance for improving the oral bioavailability of PS. This might be related to the coating structure of PHCG-PS-NLCs confirmed by AFM, FTIR, and Raman characterization. This study provide a reference value for designing suitable PS-NLC complexes without synthetic surfactants.

A self-assembly all-polysaccharide hydrogel for the aquatic heavy metal ions management and utilization

Hydrogels with a unique three-dimensional porous structure are regarded as good adsorbents to treat heavy metal ions-contaminated water. However, the post-treatment of the hydrogels after the wastewater treatment is still a big problem. We herein proposed to use the TEMPO-oxidized cellulose nanofibers (TOCN)/cationic guar gum (CGG) self-assembly hydrogel to adsorb Cu2+ from its contaminated water. The Cu2+-adsorbed hydrogel was demonstrated to be a good stress-sensing material responsive to the loading weight. In addition, the Cu2+-adsorbed hydrogel was transformed into a Cu-doped carbon aerogel after the freeze-drying and carbonization treatments and the resultant carbon aerogel exhibited good and stable electrochemical property. It had an aerial specific capacitance of 3.14 F·cm−2 when the current density was 3 mA·cm−2. Importantly, the existence of copper largely enhanced the electrochemical property of the carbon aerogel since it led to the improvement in conductivity and pseudocapacitance. This work might spur the application of hydrogel in heavy metal ions-contaminated water treatment and provide new ways to convert pollutants into products.

Charge characteristics of guar gums on the three-stage interaction mechanism with mucin to improve the mucoadhesion ability

The mucoadhesion process is essential for polysaccharide-based nutrient delivery systems. In this study, the intramolecular interactions between mucin and guar gums (GGs) with different charge characteristics going through contact, diffusion, and binding stages were explored. The contact angle analysis was used to characterize the interactions between mucin and GGs at the contact stage. The data of attenuated total reflectance-infrared spectroscopy was calculated to measure the diffusion coefficient (D) of GGs with mucin at the diffusion stage. The results showed that the interactions between the mucin and GGs at the contact and diffusion stages were mainly hydrogen bonding generated by the hydrophilic groups of the polysaccharides and mucin due to the largest contact angle and lowest D value for the neutral guar gum (GG (O)). Fluorescence spectroscopy was carried out to analyze the interactions at the binding stage and found that the interactions were mainly driven by the electrostatic interaction. The results of ΔH°<0 and ΔS°>0 at pH 7.0 indicated the strong electrostatic attraction between the mucin and cationic guar gum (CGG (+)), improving the mucoadhesion ability of the CGG (+); while the electrostatic repulsion weakened the interactions between the mucin and anionic guar gum (AGG (-)). The current discovery of the three-stage interaction mechanism makes it possible to regulate the mucoadhesion ability of the delivery system by altering the polysaccharide charge characteristics.

FIXATION OF DYE-TYPE RED AND BLUE INK HANDWRITING ON AGED PAPER

In this article, red and blue ink handwriting on aged paper was fixed by fixative to prevent handwriting from fading or diffusion during aqueous deacidification. Firstly, four fixatives were selected: polydimethyl ammonium chloride (PDDA), the quaternary ammonium salt of chitosan (HACC), cationic guar gum (CGG), and benzyl triethyl ammonium chloride (TEBAC) alcohol solution, according to their fixation effects on filter paper dyes, and derive the optimal composition ratio of the above four fixatives. Experimentally derived that PDDA has an excellent fixation effect on red ink handwriting, and HACC has an excellent fixation effect on blue ink handwriting. In addition, HACC also has a positive impact on the conservation of handwriting in real archives. The mechanical properties of aged paper were improved, and the paper fibers had no obvious change after the fixation and deacidification processes.

Modulation of composite hydrogel consisting of TEMPO-oxidized cellulose nanofibers and cationic guar gum

The applications of hydrogels are prominently affected by the modulation of their structure and performance. We herein systematically implemented the modulation of an all-polysaccharide hydrogel consisting of TEMPO-oxidized cellulose nanofibers (TOCN) and cationic guar gum (CGG). Four different factors including the carboxylate content and size of TOCN, the freezing-thawing treatment and solid content of hydrogel were studied to disclose their influence on the structure and property of TOCN/CGG hydrogel. The results indicated that the increase of carboxylate content of TOCN, the number of freezing-thawing cycles and solid content all increased the crosslinking density of hydrogel as a result of the improved interactions. Accordingly, the hydrogels exhibited more compact structures and enhanced rheological properties. The influence of TOCN size on the hydrogel structure and property was demonstrated to be dependent on the compromise between the exposed functional groups of TOCN and their ability in generating entanglements inside the hydrogel. This work helps shed light on the modulation of hydrogel structure and performance, which might facilitate the exploration of hydrogel applications.

Antibiotic‐Derived Carbon‐Nanodot‐Decorated Hydrogel for Reactive Oxygen Species‐Enhanced Anti‐Infection Through Biofilm Damage

AbstractIrreversible bacterial resistance and impenetrable biofilms have rendered conventional antibiotic therapy ineffective. Nevertheless, increasing evidence has confirmed that antibiotic carbon nanodots (CDs) exhibit potent antibacterial activity. However, the complex chemical composition of antibiotic CDs, and, hence, their antibacterial mechanism, is difficult to understand. The design of new antibiotic CDs against antibacterial resistance is an urgent requirement.In this study, kanamycin‐sulfate‐derived carbon nanodots (KCDs) are found to exhibit significant antibacterial potential with the assistance of light irradiation. Systematic analysis indicates that KCDs not only retain the active structure of kanamycin but also produce five new components modified on its surface, which are shown to inhibit the activity of Staphylococcus aureus beta‐ketoacyl‐acp synthase III (FabH) through molecular docking. Furthermore, the multifunctional hydrogels (CG‐KCDs) self‐assemble into injectable, self‐healing, and antibiofilm structures through noncovalent forces between the KCDs and cationic guar gum (CG). The results indicate that under laser, CG‐KCDs irradiation exhibits enhanced antibacterial activity in vitro by damaging bacterial biofilms in a reactive oxygen species (ROS)‐dependent manner, as determined by transcriptomics. Further, the therapeutic effects of CG‐KCDs hydrogel dressings on wound healing and tissue remodeling under laser are confirmed using an in vivo wound infection model. These results validate the potential of KCDs as efficient antibacterial agents to replace antibiotics as an anti‐infective strategy.

One-pot synthesis of a novel conductive molecularly imprinted gel as the recognition element and signal amplifier for the selective electrochemical detection of amaranth in foods

Herein, we prepared a self-crosslinked conductive molecularly imprinted gel (CMIG) using cationic guar gum (CGG), chitosan (CS), β-cyclodextrin (β-CD), amaranth (AM) and multi-walled carbon nanotubes (MWCNTs) by a simple one-pot low temperature magnetic stirring method. The imine bonds, hydrogen-bonding interactions and electrostatic attractions between CGG, CS and AM facilitated CMIG gelation, while β-CD and MWCNTs enhanced the adsorption capacity and conductivity of CMIG, respectively. Next, the CMIG was deposited onto the surface of a glassy carbon electrode (GCE). After selective removal of AM, a highly sensitive and selective CMIG-based electrochemical sensor was obtained for AM determination in foods. The CMIG allowed specific recognition of AM and could also be used for signal amplification, thus improving the sensitivity and selectivity of the sensor. Due to the high viscosity and self-healing properties of the CMIG, the developed sensor was very durable retaining a 92.1% of original current after 60 consecutive measurements. Under optimal conditions, the CMIG/GCE sensor showed a good linear response for AM detection (0.02–150 μM) with a limit of detection of 0.003 μM. AM recovery tests were performed in milk powder and white vinegar samples, yielding satisfactory recoveries (89.00%–111.00%). Furthermore, the levels of AM in two kinds of carbonated drinks were analyzed with the constructed sensor and an ultraviolet spectrophotometry method, with no significant difference found of the two methods. This work demonstrates that CMIG based electrochemical sensing platforms allow the cost-effective detection of AM, with the CMIG technology likely being widely applicable to the detection of other analytes.

Facile fabrication of self-healing, injectable and antimicrobial cationic guar gum hydrogel dressings driven by hydrogen bonds

Developing self-healing polysaccharide hydrogels offers a promising strategy for the healing of full-thickness skin wounds. However, the green and facile fabrication of self-healing polysaccharide hydrogel dressings is challenging. Herein, a novel hydrogen-bonded polysaccharide hydrogel consisting only of cationic guar gum (CG) and CuCl2 was developed by simply mixing CG and Cu2+ solution. A strong enough intermolecular hydrogen bonding could be formed between ipsilateral hydroxyl groups to induce rapid gelation. Benefiting from dynamic and reversible linkages, cationic guar gum-Cu2+ (CG-Cu) hydrogels exhibited self-healing, injectable and self-adaption. The CG-Cu hydrogels possessed favorable mechanical strength (compression strength: 50–89 kPa), excellent biocompatibility (cell viability: >95 %; hemolysis ratio: < 5 %) and satisfying antibacterial ability. In vivo degradation tests showed that the CG-Cu hydrogels could be completely degraded after 21 days. Furthermore, in-situ injected CG-Cu hydrogel dressings could perfectly cover wounds to reduce risk of infection and accelerated full-thickness skin generation. In conclusion, this study may provide a new simple and straightforward strategy to prepare self-healing polysaccharide hydrogels based on hydrogen bonding to expand its application in the field of biomedicine and tissue regeneration.

PH responsive cationic guar gum-borate self-healing hydrogels for muco-adhesion

ABSTRACT We developed a new muco-adhesive hydrogel composed of cationic guar gum (CGG) and boric acid (BA). The CGG-BA precursor solution of 0.5–2% w/v concentration exhibited fluidity at low pH (3–5), while gelation occurred within 1 min at physiological pH (7–8) conditions. Scanning electron microscopy and Fourier-transform infrared spectroscopy results confirmed the change in physical and chemical behavior, respectively, with change in pH. The pH-responsive self-healing ability was analyzed through microscopy and rheology. CGG-BA hydrogels showed good self-healing property at pH 7.4. The in vitro biocompatibility test of the hydrogel studied using NIH3T3 and NHEK cells showed that it was non-toxic at concentrations of CGG-BA below 2% w/v. Ex vivo mucoadhesive tests confirmed the hydrogel’s potential for use as a muco-adhesive. Burst pressure tests were conducted using pig esophageal mucosa and the results showed that at pH 7.4, 1% w/v CGG-BA self-healable hydrogel resisted about 8 ± 2 kPa pressure, comparable to that of Fibrin glue. This was higher than that at solution (pH 5) and brittle gel (pH 10) conditions. To confirm the good adhesive strength of the self-healable hydrogels, lap shear tests conducted, resulted in adhesive strengths measured in the range of 1.0 ± 0.5–2.0 ± 0.6 kPa, which was also comparable to fibrin glue control 1.8 ± 0.6 kPa. Hydrogel weight measurements showed that 40–80% gel lasted under physiological conditions for 10 h. The results suggest that CGG-BA hydrogel has potential as a pH responsive mucosal protectant biomaterial.

NIR as a “trigger switch” for situ distinguish superbacteria and photothermal synergistic antibacterial treatment with Ag2O particles/lignosulfonate/cationic guar gum hybrid hydrogel

The in situ identification of superbugs with the simultaneous killing of it is key to preventing human health. Here, a one-stop identification and killing platform for near-infrared (NIR) triggering was designed and constructed using lignosulfonate (LS), cationic guar gum (CG) and Ag2O NPs hydrogels (LS/CG/Ag2O). The hydrogel network is used as a fixed matrix for Ag2O NPs and a nano reactor, meanwhile 3,3′, 5,5′-tetramethylbenzidine (TMB) as a single probe sensor array for bacterial identification. In contrast to conventional methods, hybrid hydrogels have catalytic qualities through which TMB be catalyzed to generate oxidized TMB (oxTMB). The drug resistance of the same strain can be distinguished based on the different inhibition abilities of drug-resistant superbacteria in TMB and hydrogel reactions. Then, the employing of oxTMB photothermal characteristics, it can be efficiently killed in real time while being driven by a near-infrared laser. The proposed one-stop hydrogel platform paves a way for the rapid identification and killing of drug-resistant superbacteria.

Development of the phage lysin-loaded liposomes as preservatives for live clams

Exogenous applications of phage lysins against Vibrio parahaemolyticus (V. parahaemolyticus) are a challenge due to the gram-negative bacteria outer membrane barrier. This study aimed to improve the antibacterial effect of V. parahaemolyticus phage lysin Lysqdvp001 (Lys), the best-characterized lysin with lytic activity against multiple species of Vibrios, by using liposome delivery. Various kinds of Lys-loaded liposome (Lys-lip) systems were designed and tested. The antibacterial activities of cationic guar gum (CGG) containing liposomes were much higher than the other liposomes, causing >5 log10CFU/mL of reductions of V. parahaemolyticus in buffer and severely damaging the bacterial cell structure. Moreover, some CGG liposome formulations retained high antibacterial effect after both 60–80 °C heat treatments and freeze-drying. Besides, the most stable liposome formulation killed 99 % of V. parahaemolyticus in the seawater with live clams, and its depuration rate against the bacterial contaminated clams also reached 99 %.

Core-Shell Filament with Excellent Wound Healing Property Made of Cellulose Nanofibrils and Guar Gum via Interfacial Polyelectrolyte Complexation Spinning.

Natural polymer-based sutures have attractive cytocompatibility and degradability in surgical operations. Herein, anionic cellulose nanofibrils (ACNF) and cationic guar gum (CGG) are employed to produce nontoxic CGG/ACNF composite filament with a unique core-shell structure via interfacial polyelectrolyte complexation (IPC) spinning. The comprehensive characterization and application performance of the resultant CGG/ACNF filament as a surgical suture are thoroughly investigated in comparison with silk and PGLA (90% glycolide and 10% l-lactide) sutures in vitro and in vivo, respectively. Results show that the CGG/ACNF filament with the typical core-shell structure and nervation pattern surface exhibits a high orientation index (0.74) and good mechanical properties. The tensile strength and knotting strength of CGG/ACNF suture prepared by twisting CGG/ACNF filaments increase by 69.5%, and CGG/ACNF suture has a similar friction coefficient to silk and PGLA sutures. Moreover, CGG/ACNF suture with antibiosis and cytocompatibility exhibits better growth promotion of cells than silk suture, similar to PGLA suture in vitro. In addition, the stitching experiment of mice with the CGG/ACNF suture further confirms better healing properties and less inflammation in vivo than silk and PGLA sutures do. Hence, the CGG/ACNF suture with a simple preparation method and excellent application properties is promising in surgical operations.

Time-Resolved Kinetic Measurement of Microalgae Agglomeration for Screening of Polysaccharides-Based Coagulants/Flocculants.

Time-resolved monitoring of microalgae agglomeration facilitates screening of coagulants/flocculants (CFs) from numerous biopolymer candidates. Herein, a filtering-flowing analysis (FFA) apparatus was developed in which dispersed microalgal cells were separated from coagulates and flocs formed by CFs and pumped into spectrophotometer for real-time quantification. Polysaccharides-based CFs for Microcystis aeruginosa and several other microalgae were tested. Cationic hydroxyethyl cellulose (CHEC), chitosan quaternary ammonium (CQA) and cationic guar gum (CGG) all triggered coagulation obeying a pseudo-second-order model. Maximal coagulation efficiencies were achieved at their respective critical dosages, i.e., 0.086 g/gM.a. CHEC, 0.022 g/gM.a. CQA, and 0.216 g/gM.a. CGG. Although not active independently, bacterial exopolysaccharides (BEPS) aided coagulation of M. aeruginosa and allowed near 100% flocculation efficiency when 0.115 g/gM.a. CQA and 1.44 g/gM.a. xanthan were applied simultaneously. The apparatus is applicable to other microalgae species including Spirulina platensis, S. maxima, Chlorella vulgaris and Isochrysis galbana. Bio-based CFs sorted out using this apparatus could help develop cleaner processes for both remediation of harmful cyanobacterial blooms and microalgae-based biorefineries.

Rheological and fracturing characteristics of a cationic guar gum

Guar gum (GG) fracturing fluid is frequently used in the field of enhanced oil recovery. GG fracturing fluids must have increased the temperature resistance and salt tolerance due to the complexity of drilled formations. In this study, the cationic guar gum (GG-GTA) samples for fracturing fluids were successfully synthesized, which can even resist 120 °C. It can be directly prepared by formation water, even sea water. Besides hydrogen bonds and covalent bonds, the additional cationic groups can strengthen the network even more in the GG-GTA fracturing fluids, which is why the GG-GTA fracturing fluids had stronger rheological properties than the GG fracturing fluids. The GG-GTA fracturing fluids performed well in terms of temperature resistance, salt tolerance, pressure resistance, and proppant carrying capacity. In addition, the GG-GTA gel-breaking caused little damage to core permeability because it exhibited low viscosity, interfacial tension, and surface tension. These results provide a solid foundation for the application of GG-GTA fracturing fluids in oilfield production.

Highly Stretchable, Tough, and Self-Recoverable Cationic Guar Gum-Based Hydrogels for Flexible Sensors

Stretchable and tough conductive hydrogels have attracted much attention in flexible sensing electronics. However, most existing conductive hydrogels have poor strain and strength or unsatisfactory recovery capability, which cannot satisfy the requirements for stretchable electronics. In this study, a type of hybrid ionic-covalent guar hydroxypropyltrimonium chloride (cationic guar gum, CGG)-based DN hydrogel with PAM covalent and CGG-CO32– or CGG-SO42– ionic networks via a free radical polymerization and soaking process was developed to prepare high-performance strain sensors. The existence of salt ions in the CGG-based hydrogel not only induces the formation of noncovalent cross-linking points, endowing the hydrogel high mechanical performance, but also gives the hydrogel high ionic conductivity. Consequently, the obtained hybrid DN hydrogels show high tensile strength (>1.2 MPa), large elongation (>1200%), high toughness, good conductivity, and rapid self-recovery property. Significantly, by simply controlling the soaking duration, we tailored the mechanics of the hybrid DN hydrogels. As demonstrated, this hydrogel-based sensor exhibits good sensitivity, large strain sensing capability, high durability, and could detect various human motions. Our study opens up a horizon in the preparation and regulation of cationic guar gum-based hydrogels for applications in high-performance flexible sensors.