Formulation of sumatriptan succinate orodispersible tablets using chitosan and sodium starch glycolate for immediate migraine relief.

Migraine is one of the common neurological disease affecting around 23% of the Pakistani population. Prompt treatment is required to regain the functional ability of patients. The present study was designed to develop sumatriptan succinate orodispersible tablets that would quickly overcome acute migraine episodes using 22 full-factorial design. The chitosan and sodium starch glycolate were taken as independent variables; friability, disintegration, dispersion time and water absorption ratio as response variables. Eight trial formulations were generated by Design Expert® software. The main effect plots were used to check the interaction of formulations with response variables. All trial formulations showed good micromeritic properties in terms of angle of repose (19.59o-24.57°), Carr's index (17.08-24.90%) and Hausner's ratio (1.20-1.33). The tablets wetted quickly (17.1- 39 sec) in dispersion medium, showed higher water absorption ratio (188-341 sec) and disintegrated quickly (13-20 sec) with an excellent dissolution rate (94-99%). The main effect plots show interactions between the independent variables against most of the study responses. A 22 full-factorial model was found to be effective in studying the influence of formulation variables on response parameters. Both chitosan and sodium starch glycolate can be used in combination to fabricate an effective orodispersible formulation of sumatriptan succinate.

Effects of PVA and yerba mate extract on extruded films of carboxymethyl cassava starch/PVA blends for antioxidant and mechanically resistant food packaging.

Global concerns over environmental damage caused by non-biodegradable single-use packaging have sparked interest in developing biomaterials. The food packaging industry is a major contributor to non-degradable plastic waste. This study investigates the impact of incorporating different concentrations of polyvinyl alcohol (PVA) and yerba mate extract as a natural antioxidant into carboxymethyl cassava starch films to possibly use as active degradable packaging to enhance food shelf life. Films with starch and PVA blends (SP) at different ratios (SP radios of 100:0, 90:10, 80:20 and 70:30) with and without yerba mate extract (Y) were successfully produced through extrusion and thermoforming. The incorporation of up to 20 wt% PVA improved starch extrusion processing and enhanced film transparency. PVA played a crucial role in improving the hydrophobicity, tensile strength and flexibility of the starch films but led to a slight deceleration in their degradation in compost. In contrast, yerba mate extract contributed to better compost degradation of the blend films. Additionally, it provided antioxidant activity, particularly in hydrophilic and lipophilic food simulants, suggesting its potential to extend the shelf life of food products. Starch-PVA blend films with yerba mate extract emerged as a promising alternative for mechanically resistant and active food packaging.

Effect of ultrasonic power on delivery of quercetin in emulsions stabilized using octenyl succinic anhydride (OSA) modified broken japonica rice starch.

In this study, emulsions stabilized by octenyl succinic anhydride-modified broken japonica rice starch (OSA-BJRS) were prepared at different ultrasonic power intensities for the delivery, controlled release, and improved bioavailability of quercetin. The OSA-BJRS emulsions ultrasonicated at 400 W exhibited the highest encapsulation efficiency (89.37 %) and loading efficiency (58.34 %) of quercetin, the smallest volume-average droplet diameter (0.51 µm) and polydispersity index (0.19), the highest absolute value of the ζ-potential (26.73 mV), and the highest apparent viscosity and viscoelasticity. The oxidation stability, storage stability, thermal stability, and salt ion stability of the emulsions were also notably improved by the ultrasonication treatment. In addition, the results of the simulated in vitro digestion demonstrated that the ultrasonicated OSA-BJRS emulsions had an enhanced quercetin delivery performance and could stably transport quercetin to the small intestine for digestion. The OSA-BJRS emulsion ultrasonicated at 400 W exhibited the highest cumulative release rate (95.91 %) and the highest bioavailability (30.48 %) of quercetin. This suggests that OSA-BJRS emulsions prepared by ultrasonication can be considered effective delivery systems for hydrophobic functional components.

Effects of cold plasma pretreatment combined with sodium periodate on property enhancement of dialdehyde starch prepared using native maize starch.

This study represents the inaugural investigation into the effect of cold plasma (CP) pretreatment combined with sodium periodate on the preparation of dialdehyde starch (DAS) from native maize starch and its consequent effects on the properties of DAS. The findings indicate that the maize starch underwent etching by the plasma, leading to an increase in the particle size of the starch, which in turn weakened the rigid structure of the starch and reduced its crystallinity. Concurrently, the plasma treatment induced cleavage of the starch molecular chain, resulting in a decrease in the viscosity of the starch and an enhancement of its fluidity. These alterations facilitated an increased contact area between the starch and the oxidising agent sodium periodate, thereby augmenting the efficiency of the DAS preparation reaction. Consequently, the aldehyde group content was elevated by 9.98 % compared to the conventional DAS preparation methodology. Therefore, CP could be an efficient and environmentally friendly non-thermal processing method to assist starch oxidation for DAS preparation and property enhancement.

Facilitating safe and sustained submucosal lift through an endoscopically injectable shear-thinning carboxymethyl starch sodium hydrogel.

Traditional submucosal filling materials frequently show insufficient lifting height and duration during clinical procedures. Here, the anionic polysaccharide polymer sodium carboxymethyl starch and cationic Laponite to prepare a hydrogel with excellent shear-thinning ability through physical cross-linking, so that it can achieve continuous improvement of the mucosal cushion through endoscopic injection. The results showed that the hydrogel (56.54 kPa) had a lower injection pressure compared to MucoUp (68.56 kPa). The height of submucosal lifting height produced by hydrogel was higher than MucoUp, and the height maintenance ability after 2 h was 3.20 times that of MucoUp. At the same time, the hydrogel also showed satisfactory degradability and biosafety, completely degrading within 200 h. The hemolysis rate is as low as 0.76 %, and the cell survival rate > 80 %. Subcutaneous implantation experiments confirmed that the hydrogel showed no obvious systemic toxicity. Animal experiments clearly demonstrated the in vivo feasibility of using hydrogels for submucosal uplift. Furthermore, successful endoscopic submucosal dissection was executed on a live pig stomach, affirming the capacity of hydrogel to safely and effectively facilitate submucosal dissection and mitigate adverse events, such as bleeding. These results indicate that shear-thinning hydrogels have a wide range applications as submucosal injection materials.

Schiff base functionalized dialdehyde starch for enhanced removal of Cu (II): Preparation, performances, DFT calculations.

Dialdehyde starch modified by 2-hydrazinopyridine (HYD-DAS) based on the reaction of dialdehyde starch (DAS) and 2-hydrazinopyridine was synthesized and characterized by FT-IR spectra, element analysis and SEM. HYD-DAS can efficiently adsorb Cu (II) ion to demonstrate visual color changes from yellow to dark brown in aqueous solutions. The influence on HYD-DAS to Cu (II) adsorption including pH value of solution, isotherm, kinetics, thermodynamics and possible mechanism had also been examined. Batch experiments indicate that HYD-DAS's to Cu (II) adsorption reaches equilibrium within 250 min, and its adsorption capacity and rate are 195.75 mg/g and 98.63 %, respectively. Moreover, HYD-DAS to Cu (II) adsorption remains robust and underscoring after five cycles to exhibit good selectivity and reusability. Kinetics studies suggest the absorption process follows a quasi-second-order with isotherms aligning to the Langmuir monolayer model, and thermodynamics reveals that it is a spontaneous endothermic nature of adsorption. Based on the analyses of XPS and DFT calculations, a possible mechanism for HYD-DAS to Cu (II) adsorption is that Cu (II) combined with nitrogen atoms from Schiff base and hydrazine pyridine ring in HYD-DAS.

Enhancing the properties of soy protein isolate and dialdehyde starch films for food packaging applications through tannic acid crosslinking.

The utilization of naturally derived biodegradable polymers, including proteins, polysaccharides, and polyphenols, holds significant promise in addressing environmental concerns and reducing reliance on nonrenewable resources. This study aimed to develop films with enhanced UV resistance and antibacterial capabilities by covalently cross-linking soy protein isolate (SPI) with dialdehyde starch (DAS) through the incorporation of tannic acid (TA). The covalent crosslinking of TA with DAS and SPI was shown to establish a stable chemical cross-linking network. The tensile strength of the resulting SPI/DAS/15TA film exhibited a remarkable increase of 208.27 % compared to SPI alone and 52.99 % compared to SPI/DAS film. Notably, the UV absorption range of SPI/DAS/10TA films extended from 200 nm to 389 nm. This augmentation can be attributed to the oxidation of TA's phenolic hydroxyl groups to quinone under alkaline conditions, which then facilitated cross-linking with the SPI chain via Michael addition and Schiff base reactions. Furthermore, the film demonstrated robust antibacterial properties due to the incorporation of TA. Collectively, the observed properties highlight the significant potential of the SPI/DAS/10TA film for applications in food packaging, where its enhanced mechanical strength, UV resistance, and antibacterial characteristics can contribute to improved product preservation and safety.

Removal of Pb (II) and Zn (II) in the mineral beneficiation wastewater by using cross-linked carboxymethyl starch-g-methacrylic acid as an effective flocculant.

The cross-linked carboxymethyl starch-g-methacrylic acid (CCMS-g-MAA) was prepared by using grafting and micro-cross-linking in the one-pot preparation process. CCMS-g-MAA presented high removal capacity of Pb (II) of 57.13 mg/g at pH = 4 and high removal capacity of Zn (II) of 51.41 mg/g at pH = 5 by using a sample dosage of 0.68 g/L. Characterization results of FTIR, TG, and XRD illustrate that methacrylic acid and sodium tri-metaphosphate were successfully introduced into the structure of carboxymethyl starch. SEM characterization presented that the sample particles were amorphous aggregates with surface voids, which was favorable for the adsorption of heavy metal ions from wastewater. Adsorption isotherm results indicated that Freundlich equation could be better used to describe the adsorption process of metal ions on CCMS-g-MAA. The adsorption kinetic results indicated that the pseudo-second-order model is more suitable to describe this removal process. XPS results indicated that metal ions interacted with functional groups on the surface of flocculant, especially carboxyl groups. The removal process may be purposed that metal ions were adsorbed by porous material, and then combined with surface functional groups of the flocculant via electrostatic interaction, chelation or ion exchange. Subsequently, metal ions were separated from the wastewater with flocs precipitated in the bottom of solution via bridging and patching. The obtained results illustrated that CCMS-g-MAA was an effective material for the treatment of wastewater containing polymetallic ions besides mineral beneficiation wastewater supported by its excellent regeneration.

Recent advances on the preparation conditions, structural characteristics, physicochemical properties, functional properties and potential applications of dialdehyde starch: A review.

Starch, a natural storage polysaccharide of plant kingdom, has many industrial applications. However, native starch has some inherent shortages, which can be overcome by structural modification. Dialdehyde starch, one kind of oxidized starch produced by periodate oxidation, has good physical properties and bioactivities with wide applications in different fields. Dialdehyde starch is typically achieved by oxidizing native starch slurry through periodate oxidation under controlled reaction conditions. Several factors including the source of starch, the type of oxidant, the molar ratio of oxidant to starch, reaction temperature, reaction time and solution pH value can influence the synthesis of dialdehyde starch. Dialdehyde starch shows different spectroscopic/chromatographic characters and physicochemical properties from native starch. Moreover, dialdehyde starch exhibits good antioxidant activity, antimicrobial activity and cross-linking property. Based on these functional properties, dialdehyde starch has shown application potentials in food packaging, thermoplastic production, enzyme immobilization, heavy metal ion adsorption, drug delivery, wood adhesion and leather tanning. In this review, the preparation conditions, structural characteristics, physicochemical properties, functional properties and potential applications of dialdehyde starch are summarized for the first time. The future research and development prospects of dialdehyde starch are also discussed.

Effect of electrostatic repulsion on barrier properties and thermal performance of gelatin films by carboxymethyl starch, and application in food cooking.

Carboxymethyl starch (CST) was introduced to improve gelatin films and its practical application as edible high-performance films for food packaging and cooking was also investigated. The gelatin films modified by carboxymethyl starch exhibited the transparent appearance, tensile strength, barrier properties (oxygen, water vapor and UV light), and thermal performance (TGA, thermal shrinkage and heat-sealing strength). Resulting from the effect of electrostatic interaction modes on the properties of films, electrostatic repulsion could surpass electrostatic attraction in improving the tensile strength, oxygen barrier property and thermal stability of the films probably due to extensive physical entanglement without aggregation. Analysis of FTIR, zeta potential, interfacial dilatational rheology, shear rheological properties, XRD, Raman, SEM and AFM suggested that hydrogen bonding and electrostatic repulsion contributed to the excellent performance. The packaged food could also be cooked with the prepared film for porridge; and the film slightly influenced the shear rheological properties of porridge and imposed little effect on the odors (Electronic-Nose) of porridge. Hence, the gelatin films modified by carboxymethyl starch could potentially work as the edible inner packaging or the edible quantitative packaging for food, offer convenience for consumers, reduce the packaging waste and avoid an extra burden on environment.

Carboxymethyl Starch Films as Enteric Coatings: Processing and Mechanistic Insights.

This study proposes the application of carboxymethyl starch derivatives as tablet coatings affording gastro-protection. Carboxymethyl starch (CMS) films were obtained by casting of aqueous filmogenic starch solutions with or without plasticizers and their structural organization was followed using Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD). Together with data from mechanical tests (tensile strength, elongation, Young's modulus) the results were used to select filmogenic formulations adapted for coatings of tablets. The behaviour of these films was evaluated in simulated gastric and intestinal fluids. The effect of plasticizers (glycerol and sorbitol) on the starch organization, on the rate of drying of the films and on the water vapor absorption was also analyzed. Various types of starch have been compared and the best results were found with high amylose starch (HAS) that was carboxymethylated in an aqueous phase to obtain carboxymethyl high amylose starch (CMHAS). The CMHAS coating solutions containing sorbitol or glycerol as plasticizers have been applied with an industrial pan coater and the final tablets exhibited a good gastro-resistance (up to 2h) in simulated gastric fluid followed by disintegration in simulated intestinal fluid (SIF). The CMHAS derivatives present a high potential as coatings for nutraceutical and pharmaceutical solid dosage forms.

Preparation of magnetic dialdehyde starch-immobilized phospholipase A1 and acyl transfer in reflection.

In this paper, using a coprecipitation method to prepare Fe3O4 magnetic nanoparticles (Fe3O4 MNPS), magnetic dialdehyde starch nanoparticles with immobilized phospholipase A1 (MDSNIPLA) were successfully prepared by using green dialdehyde starch (DAS) instead of glutaraldehyde as the crosslinking agent. The Fe3O4 MNPS was characterized by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), the Brunauer-Emmett-Teller (BET) surface area analysis method, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) et al. The results showed that the alkaline resistance and acid resistance of the enzyme were improved after the crosslinking of DAS. After repeated use (seven times), the relative activity of MDSNIPLA reached 56 %, and the magnetic dialdehyde starch nanoparticles (MDASN) had good carrier performance. MDSNIPLA was applied to enzymatic hydrolysis of phospholipids in the soybean oil degumming process. The results showed that the acyl transfer rate of sn-2-HPA was 14.01 %, and the content of free fatty acids was 1.144 g/100 g after 2 h reaction at 50 °C and pH 5.0 with appropriate boric acid. The immobilized enzyme has good thermal stability and storage stability, and its application of soybean oil improves the efficiency of the oil.

Composite formation of whey protein isolate and OSA starch for fabricating high internal phase emulsion: A comparative study at different pH and their application in biscuits.

The composites formed by whey protein isolate (WPI) and octenyl succinate anhydride (OSA)-modified starch were characterized with a focus on the effect of pH, and their potential in fabricating high internal phase emulsions (HIPEs) as fat substitutes was evaluated. The particles obtained at pH 3.0, 6.0, 7.0, and 8.0 presented a nanosized distribution (122.04 ± 0.84 nm-163.24 ± 4.12 nm) while those prepared at pH 4.0 and 5.0 were remarkably larger. Results from the shielding agent reaction and Fourier transform infrared spectroscopy (FT-IR) showed that the interaction between WPI and OSA starch was mainly hydrophobic at pH 3.0-5.0, while there was a strong electrostatic repulsion at pH 6.0-8.0. A quartz crystal microbalance with dissipation (QCM-D) study showed that remarkably higher ΔD and lower Δf/n were observed at pH 3.0-5.0 after successive deposition of WPI and OSA starch, whereas slight changes were noted for those made at higher pH values. The WPI-OSA starch (W-O) composite-based HIPEs made at pH 3.0 and 6.0-8.0 were physically stable after long-term storage, thermal treatment, or centrifugation. Incorporation of HIPE into the biscuit formula yielded products with a desirable sensory quality.

High-strength, antifogging and antibacterial ZnO/carboxymethyl starch/chitosan film with unique "Steel Wire Mesh" structure for strawberry preservation.

In this work, a multifunctional preservative film of ZnO/carboxymethyl starch/chitosan (ZnO/CMS/CS) with the unique "Steel Wire Mesh" structure is fabricated by the chemical crosslinked of ZnO NPs, CMS and CS. Unlike traditional nano-filled polymer film, the formation of the "Steel Wire Mesh" structure of ZnO/CMS/CS film is based on the synergistic effect of ZnO NPs filled CMS/CS and the coordination crosslinked between CMS/CS and Zn2+ derived from ZnO NPs. Thanks to the "Steel Wire Mesh" structure, the tensile strength and water vapor barrier of 2.5ZnO/10CMS/CS film are 2.47 and 1.73 times than that of CS film, respectively. Furthermore, the transmittance of 2.5ZnO/10CMS/CS film during antifogging test is close to 89 %, confirming its excellent antifogging effects. And the 2.5ZnO/10CMS/CS film also exhibits excellent long-acting antibacterial activity (up to 202 h), so it can maintain the freshness and appearance of strawberries at least 5 days. More importantly, the 2.5ZnO/10CMS/CS film is sensitive to humidity changes, which achieves real-time humidity monitoring of the fruit storage environment. Note that the preparation method of the film is safe, simple and environmentally friendly, and its excellent degradation performance will not bring any problems of food safety and environmental pollution.

Fabrication and characterization of complex coacervates utilizing gelatin and carboxymethyl starch.

BACKGROUND: Modified polysaccharides have greatly expanded applications in comparison with native polysaccharides due to their improved compatibility and interactions with proteins and active compounds in food-related areas. Nonetheless, there is a noticeable dearth of research concerning the utilization of carboxymethyl starch (CMS) as a microcapsule wall material in food processing, despite its common use in pharmaceutical delivery. The development of an economical and safe embedding carrier using CMS and gelatin (GE) holds immense importance within the food-processing industry. In this work, the potential of innovative coacervates formed by the combination of GE and CMS as a reliable, stable, and biodegradable embedding carrier is evaluated by turbidity measurements, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and rheological measurements. RESULTS: The results indicate that GE-CMS coacervates primarily resulted from electrostatic interactions and hydrogen bonding. The optimal coacervation was observed at pH 4.6 and with a GE/CMS blend ratio of 3:1 (w/w). However, the addition of NaCl reduced coacervation and made it less sensitive to temperature changes (35-55 °C). In comparison with individual GE or CMS, the coacervates exhibited higher thermal stability, as shown by TGA. X-ray diffraction analysis shows that the GE-CMS coacervates maintained an amorphous structure. Rheological testing reveals that the GE-CMS coacervates exhibited shear-thinning behavior and gel-like properties. CONCLUSION: Overall, attaining electroneutrality in the mixture boosts the formation of a denser structure and enhances rheological properties, leading to promising applications in food, biomaterials, cosmetics, and pharmaceutical products. © 2023 Society of Chemical Industry.

Multifunctional organohydrogel via the synergy of dialdehyde starch and glycerol for motion monitoring and sign language recognition.

Conductive hydrogel which belongs to a type of soft materials has recently become promising candidate for flexible electronics application. However, it remains difficult for conductive hydrogel-based strain sensors to achieve the organic unity of large stretchability, high conductivity, self-healing, anti-freezing, anti-drying and transparency. Herein, a multifunctional conductive organohydrogel with all of the above superiorities is prepared by crosslinking polyacrylamide (PAM) with dialdehyde starch (DAS) in glycerol-water binary solvent. Attributing to the synergy of abundant hydrogen bonding and Schiff base interactions caused by introducing glycerol and dialdehyde starch, respectively, the organohydrogel achieved balanced mechanical and electrical properties. Besides, the addition of glycerol promoted the water-locking effects, making the organohydrogel retain the superior mechanical properties and conductivity even at extreme conditions. The resultant organohydrogel strain sensor exhibits desirable sensing performance with high sensitivity (GF = 6.07) over a wide strain range (0-697 %), enabling the accurate monitoring of subtle body motions even at -30 °C. On the basis, a hand gesture monitor system based on the organohydrogel sensors arrays is constructed using machine learning method, achieving a considerable sign language recognition rate of 100 %, and thus providing convenience for communications between the hearing or speaking-impaired and general person.

Hydroxypropyl methylcellulose/carboxymethyl starch/zinc oxide porous nanocomposite films for wound dressing application.

Because of low moisture uptake, water vapor transmission rate, oxygen transmission rate, swelling capacity and no antibacterial activity of hydroxypropyl methylcellulose (HPMC) film, carboxymethyl starch (CMS) and zinc oxide nanoparticles (ZnO-NPs) were incorporated in order to improve its limitations for wound dressing application. The infrared shifted peak of OH stretching and OH bending in HPMC/CMS blended films was detected due to hydrogen bond formation between HPMC and CMS. Scanning electron images of HPMC/CMS blended films exhibited porous structure. In addition, swelling degree, moisture uptake, water vapor transmission rate and oxygen transmission rate of HPMC/CMS blended films with various contents of CMS clearly increased compared to HPMC film. Moreover, HPMC/CMS nanocomposite films loaded with ZnO-NPs showed good antibacterial activity against Staphylococcus aureus and Escherichia coli, revealing their potential for wound dressing application. Percentage of crystallinity, cytotoxicity, mechanical and thermal properties were also examined.

Hydrogel beads based on carboxymethyl cassava starch/alginate enriched with MgFe2O4 nanoparticles for controlling drug release.

Implementing novel oral drug delivery systems with controlled drug release behavior is valuable in cancer therapy. Herein, a green synthetic approach based on the sol-gel technique was adopted to prepare MgFe2O4 nanoparticles at different calcination temperatures using citric acid as a chelating/combustion agent. In this context, pH-responsive and magnetic carboxymethyl starch/alginate hydrogel beads (CMCS-SA) containing the MgFe2O4 nanoparticles were developed as potential drug carriers for the anticancer drug (Doxorubicin, Dox) release in simulated gastrointestinal fluids. Furthermore, in vitro release behaviors validated that these beads illustrated excellent stability in the simulated stomach liquids. In contrast, the data in simulated intestinal fluids showed sustained release of Dox because of their pH-sensitive swelling characteristics. Notably, applying an external magnetic field (EMF) could accelerate drug release from the beads. The in vitro release of drugs from gel beads was mainly accomplished by a combination of diffusion, swelling and erosion. Moreover, the cell cytotoxicity test and laser confocal results showed no harmful effects on normal cells (3T3) but were significant cytotoxic to colon cancer cell lines (HCT116) by drug-loaded hydrogel beads. Therefore, the prepared gel beads could be qualified as latent platforms for controlling the release of anticancer drugs in cancer treatment.

Dialdehyde Starch Nanocrystals as a Novel Cross-Linker for Biomaterials Able to Interact with Human Serum Proteins.

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5-15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.

A hydrogel sensor driven by sodium carboxymethyl starch with synergistic enhancement of toughness and conductivity.

Conductive hydrogels are potential materials for fabricating wearable strain sensors owing to their excellent mechanical properties and high conductivity. However, it is a challenge to simultaneously enhance the mechanical properties and conductivity of hydrogels. Herein, a simple strategy was proposed for concurrently enhancing the mechanical properties and conductivity of the wearable hydrogel sensors by introducing carboxymethyl starch sodium (CMS). The introduction of CMS not only dramatically enhanced the mechanical performance of the hydrogel due to hydrogen bonding and electrostatic interaction, but also improved the conductivity of the hydrogel owing to the existence of sodium ions. As a result, the hydrogel sensors with excellent durability and stability could repeatedly detect and distinguish various human activities, including walking, chewing and speaking. Meanwhile, multiple sensors are also assembled into a 3D sensor array for detecting the three-dimensional distribution of stress and strain. Moreover, the peaks of EMG signals and the waveforms of ECG signals could be recorded because the hydrogel sensor presented super sensitivity and fast response. Therefore, the multifunctional hydrogel presented remarkable potential for applications in human medical diagnosis, health monitoring and artificial intelligence.