Chronological-Programmed Black Phosphorus Hydrogel for Responsive Modulation of the Pathological Microenvironment in Myocardial Infarction.

Electroactive hydrogels have garnered extensive interest as a promising approach to myocardial tissue engineering. However, the challenges of spatiotemporal-specific modulation of individual pathological processes and achieving nontoxic bioresorption still remain. Herein, inspired by the entire postinfarct pathological processes, an injectable conductive bioresorbable black phosphorus nanosheets (BPNSs)-loaded hydrogel (BHGD) was developed via reactive oxide species (ROS)-sensitive disulfide-bridge and photomediated cross-linking reaction. Significantly, the chronologically programmed BHGD hydrogel can achieve graded modulation during the inflammatory, proliferative, and maturation phases of myocardial infarction (MI). More details, during early infarction, the BHGD hydrogel can effectively reduce ROS levels in the MI area, inhibit cellular oxidative stress damage, and promote macrophage M2 polarization, creating a favorable environment for damaged myocardium repair. Meanwhile, the ROS-responsive structure can protect BPNSs from degradation and maintain good conductivity under MI microenvironments. Therefore, the BHGD hydrogel possesses tissue-matched modulus and conductivity in the MI area, facilitating cardiomyocyte maturation and electrical signal exchange, compensating for impaired electrical signaling, and promoting vascularization in infarcted areas in the maturation phase. More importantly, all components of the hydrogel degrade into nontoxic substances without adverse effects on vital organs. Overall, the presented BPNS-loaded hydrogel offers an expandable and safe option for clinical treatment of MI.

Large-Scale Fabrication of Freestanding Polymer Ultrathin Porous Membranes for Transparent Transwell Coculture Systems.

Advancements in cell coculture systems with porous membranes have facilitated the simulation of human-like in vitro microenvironments for diverse biomedical applications. However, conventional Transwell membranes face limitations in low porosity (ca. 6%) and optical opacity due to their large thickness (ca. 10 µm). In this study, we demonstrated a one-step, large-scale fabrication of freestanding polymer ultrathin porous (PUP) membranes with thicknesses of hundreds of nanometers. PUP membranes were produced by using a gap-controlled bar-coating process combined with polymer blend phase separation. They are 20 times thinner than Transwell membranes, possessing 3-fold higher porosity and exhibiting high transparency. These membranes demonstrate outstanding molecular permeability and significantly reduce the cell-cell distance, thereby facilitating efficient signal exchange pathways between cells. This research enables the establishment of a cutting-edge in vitro cell coculture system, enhancing optical transparency, and streamlining the large-scale manufacturing of porous membranes.

Injectable spontaneously formed asymmetric adhesive hydrogel with controllable removal for wound healing.

Healing large-scale wounds has been a long-standing challenge in the field of biomedicine. Herein, we propose an injectable oxidated sodium alginate/gelatin/3,3'-dithiobis(propionic hydrazide)-aurum (Alg-CHO/gelatin/DTPH-Au) hydrogel filler with asymmetric adhesion ability and removability, which is formed by the Schiff-base reaction between aldehyde-based sodium alginate and multi-amino crosslinkers (gelatin and DTPH), combined with the coordination interaction between Au nanoparticles and disulfide bond of DTPH. Consequently, the prepared Alg-CHO/gelatin/DTPH-Au hydrogel exhibits high mechanical properties and injectable behaviors owing to its multiple-crosslinked interactions. Moreover, because various types of interaction bonding form on the contact side with the tissue, denser crosslinking of the upper layer relative to the lower layer occurs. Combined with the temperature difference between the upper and lower surfaces, this results in asymmetric adhesive properties. Owing to the photothermal effect, the reversible coordination interaction between Au nanoparticles and DTPH and the change in the triple helix structure of gelatin to a coil structure impart the filler-phased removability and antibacterial ability. The choice of all natural polymers also allows for favorable degradability of the wound filler and outstanding biocompatibility. Based on these features, this versatile wound filler can achieve a wide range of applications in the field of all-skin wound repair.

A Zwitterionic Hydrogel with Anti-Oxidative and Anti-Inflammatory Properties for the Prevention of Peritoneal Adhesion by Inhibiting Mesothelial-Mesenchymal Transition.

Postoperative peritoneal adhesion is a serious clinical complication. Various hydrogel barriers have been developed to prevent peritoneal adhesion. However, it remains a challenge to design a hydrogel with desirable physicochemical properties and bioactivities. In this study, a zwitterionic polysaccharide-based multifunctional hydrogel is developed using epigallocatechin-3-gallate (EGCG) to prevent postoperative abdominal adhesion. This hydrogel is simple to use and has desirable properties, such as excellent injectability, self-healing, and non-swelling properties. The hydrogel also has ultralow fouling capabilities, such as superior bactericidal performance, cell and protein adhesion, and low immunogenicity resistance. Moreover, the hydrogel exhibits good antioxidant activity, which is attributed to the integration of EGCG. Furthermore, the detailed mechanism from in vivo and in vitro experimental studies illustrates that hydrogel compositions can synergistically prevent adhesion formation through multiple pathways, including anti-inflammatory and antioxidant capabilities and inhibition effects on the mesothelial-mesenchymal transition (MMT) process induced by transforming growth factor (TGF-ß). In summary, this zwitterionic multifunctional hydrogel has great potential to prevent postoperative adhesion formation in the clinical setting.

Zwitterionic Targeting Doxorubicin -Loaded Micelles Assembled by Amphiphilic Dendrimers with Enhanced Antitumor Performance.

Chemotherapy is the main method of treating malignant tumors in clinical treatment. However, the commonly used chemotherapeutic drugs have the disadvantages of high biological toxicity, poor water solubility, low targeting ability, and high side effects. Zwitterionic micelles assembled by amphiphilic dendrimers modified with zwitterionic groups and targeting ligand should largely overcome these shortcomings. Herein, the zwitterionic group and targeting peptide c(RGDfC) were modified on the surface of generation 2 poly(propylene imine) dendrimers (G2 PPI), which was conjugated with hydrophobic N-(2-mercaptoethyl) oleamide to form amphiphilic dendrimers (PPIMYRC). PPIMYRC self-assembled into micelles with doxorubicin (DOX) loaded in the interior of micelles to prepare DOX-loaded micelles (PPIMYRC-DOX micelles). The PPIMYRC-DOX micelles had great stability in fibrinogen and pH-responsive drug release. Furthermore, PPIMYRC-DOX micelles had higher cellular uptake rates than free DOX, resulting in higher cytotoxicity of PPIMYRC-DOX micelles than that of free DOX. More importantly, PPIMYRC-DOX micelles inhibited tumors much better than free DOX. The tumor inhibition rate of PPIMYRC-DOX micelles was as high as 93%. Taken together, PPIMYRC-DOX micelles were assembled by amphiphilic dendrimers with the zwitterionic and targeting groups, which enhanced the therapeutic effect of DOX and reduced its side effects. The prepared targeting nanodrug has great potential for further application in antitumor therapy.

Zwitterionic Polysaccharide-Based Hydrogel Dressing as a Stem Cell Carrier to Accelerate Burn Wound Healing.

Stem cell therapy integrated with hydrogels has shown promising potential in wound healing. However, the existing hydrogels usually cannot reach the desired therapeutic efficacy for burn wounds due to the inadaptability to wound shape and weak anti-infection ability. Moreover, it is difficult to improve the environment for the survival and function of stem cells under complicated wound microenvironments. In this study, an injectable and self-healing hydrogel (DSC), comprising sulfobetaine-derived dextran and carboxymethyl chitosan, is fabricated through a Schiff-base reaction. Meanwhile, the DSC hydrogel shows high nonfouling properties, including resistance to bacteria and nonspecific proteins; moreover, the prepared hydrogel can provide a biomimetic microenvironment for cell proliferation whilst maintaining the stemness of adipose-derived stem cells (ADSCs) regardless of complex microenvironments. In burnt murine animal models, the ADSCs-laden hydrogel can significantly accelerate wound healing rate and scarless skin tissue regeneration through multiple pathways. Specifically, the ADSCs-laden DSC hydrogel can avoid immune system recognition and activation and thus reduce the inflammatory response. Moreover, the ADSCs-laden DSC hydrogel can promote collagen deposition, angiogenesis, and enhance macrophage M2 polarization in the wound area. In summary, sulfobetaine-derived polysaccharide hydrogel can serve as a versatile platform for stem cell delivery to promote burn wound healing.

An Intrapericardial Injectable Hydrogel Patch for Mechanical-Electrical Coupling with Infarcted Myocardium.

Although hydrogel-based patches have shown promising therapeutic efficacy in myocardial infarction (MI), synergistic mechanical, electrical, and biological cues are required to restore cardiac electrical conduction and diastolic-systolic function. Here, an injectable mechanical-electrical coupling hydrogel patch (MEHP) is developed via dynamic covalent/noncovalent cross-linking, appropriate for cell encapsulation and minimally invasive implantation into the pericardial cavity. Pericardial fixation and hydrogel self-adhesiveness properties enable the MEHP to highly compliant interfacial coupling with cyclically deformed myocardium. The self-adaptive MEHP inhibits ventricular dilation while assisting cardiac pulsatile function. The MEHP with the electrical conductivity and sensitivity to match myocardial tissue improves electrical connectivity between healthy and infarcted areas and increases electrical conduction velocity and synchronization. Overall, the MEHP combined with cell therapy effectively prevents ventricular fibrosis and remodeling, promotes neovascularization, and restores electrical propagation and synchronized pulsation, facilitating the clinical translation of cardiac tissue engineering.

Microgel reinforced zwitterionic hydrogel coating for blood-contacting biomedical devices.

Zwitterionic hydrogels exhibit eminent nonfouling and hemocompatibility. Several key challenges hinder their application as coating materials for blood-contacting biomedical devices, including weak mechanical strength and low adhesion to the substrate. Here, we report a poly(carboxybetaine) microgel reinforced poly(sulfobetaine) (pCBM/pSB) pure zwitterionic hydrogel with excellent mechanical robustness and anti-swelling properties. The pCBM/pSB hydrogel coating was bonded to the PVC substrate via the entanglement network between the pSB and PVC chain. Moreover, the pCBM/pSB hydrogel coating can maintain favorable stability even after 21 d PBS shearing, 0.5 h strong water flushing, 1000 underwater bends, and 100 sandpaper abrasions. Notably, the pCBM/pSB hydrogel coated PVC tubing can not only mitigate the foreign body response but also prevent thrombus formation ex vivo in rats and rabbits blood circulation without anticoagulants. This work provides new insights to guide the design of pure zwitterionic hydrogel coatings for biomedical devices.

Combined treatment of xyloglucan derivative hydrogel and anti-C5a receptor antibody in preventing peritoneal adhesion.

Postoperative peritoneal adhesion is a common complication after surgery with high morbidity. In addition to improving surgical operations, medical therapy and physical barriers are the two main ways to prevent postoperative peritoneal adhesion. Satisfactory efficacy is not often obtained by the single antiadhesion method, and the combination of barrier therapy and antiadhesion drugs has attracted more attention. In this study, we first demonstrated that aberrant complement activation was associated with peritoneal injury and inflammatory responses. Correspondingly, blocking the C5a-C5aR axis reaction effectively reduced inflammatory reactions. Therefore, we creatively developed an integrated treatment of xyloglucan derivative (mXG) hydrogel and intravenous anti-C5a receptor antibody (anti-C5aRab) aimed at peritoneal adhesion, and then systematically evaluated the therapeutic efficacy using a sidewall defect-cecum abrasion model in mice. In vitro and in vivo experiments showed that the mXG hydrogel had good biocompatibility and degradability and could serve as a safe anti-adhesion barrier. The results showed that anti-C5aRab treatment could significantly inhibit peritoneal adhesions by reducing neutrophil infiltration and the expression of phosphorylated Smad2. Taken together, the mXG hydrogel integrated with anti-C5aRab showed superior antiadhesion performance and holds promising clinical applications in preventing peritoneal adhesion. STATEMENT OF SIGNIFICANCE: Postoperative peritoneal adhesion is an urgent problem to be solved after surgery. Previously, a biodegradable and thermoreversible xyloglucan derivative (mXG) hydrogel was developed that effectively prevented postoperative peritoneal adhesions, but obvious inflammatory responses and proliferation could still be observed. In addition, aberrant complement activation is associated with a variety of inflammatory diseases. We demonstrated that aberrant complement activation is involved in peritoneal adhesion. In this work, mXG hydrogel and intravenous anti-C5a receptor antibody (anti-C5aRab) were integrated to address peritoneal adhesions. The anti-C5aRab reduced the inflammatory responses. In addition, the mXG hydrogel was easy to use and effectively isolated the wound surface at the local injury site. Overall, this integrated treatment significantly improved the antiadhesion effect.

Bio-Inspired Antibacterial Hydrogel Adhesives with High Adhesion Strength.

Traditional adhesives such as cyanoacrylate glue are mostly solvent-based. They are facing the problem of insufficient adhesion to some substrates, and also from the drawback of volatilization and release of small organic molecules in the process of usage. Therefore, a novel adhesive with non-irritating, high adhesive strength, and antibacterial properties is highly required. In this study, a full physically crosslinked zwitterionic poly(betaine sulfonate methacrylate) (PSBMA) hydrogel is proposed. The physical crosslinking interactions endow the hydrogel with good self-healing properties. Furthermore, the pure physical crosslinking hydrogel can form PSBMA powder adhesive after lyophilization and return to the hydrogel state after hydration. The mechanical properties of PSBMA adhesive can be modulated via adjusting the solid content and initiator dosage. Following the cure process similar to that of snail mucus or insect exoskeletons in nature, the adhesion of the PSBMA adhesive is improved at least 100 times than its wet state. In addition, the PSBMA adhesive is easy to be removed due to the dissociation of cross-linked structures in saltwater environments. Moreover, PSBMA adhesive with antifouling properties can effectively prevent the adhesion of proteins and bacteria, which shows potential applications in the assembly of medical devices.

Facile preparation of a thermosensitive and antibiofouling physically crosslinked hydrogel/powder for wound healing.

To improve the therapeutic effect of a hydrogel on damaged tissue, a series of hydroxybutyl chitosan (HBC) and poly(sulfobetaine methacrylate) (PSBMA) composite hydrogels (HBC-PSB) with thermosensitivity, self-healing, antibiofouling, and synergistic antibacterial activity are prepared by mechanical blending. The electrostatic interaction among PSBMA and hydrophobic association among HBC are the main drive force to form a full physically crosslinked hydrogel. HBC can avoid the aggregation and precipitation of PSBMA caused by intermolecular strong association. Meanwhile, the existence of the PSBMA network can promote the sol-gel transition of HBC. Due to the reversible physical crosslinking, the HBC-PSB hydrogel shows excellent self-healing behaviors, and can be stored as dry powder. Intriguingly, the composite hydrogel has good synergistic antibacterial performance via the anti-protein adhesion ability of the PSBMA network and bactericidal ability of the HBC network. Based on these results, a sidewall defect-cecum abrasion model and an infected full-thickness skin defect model are used to investigate the application of the prepared HBC-PSB hydrogel in postoperative anti-adhesion and healing of infected wounds, respectively. The results suggest that the HBC-PSB hydrogel can completely cover the irregular damaged tissue surface, moreover, it can effectively decrease the formation of postoperative adhesion and improve the healing speed of infected wounds via reducing the adhesion and growth of bacteria. Overall, we propose that the HBC-PSB hydrogel is a promising candidate in biomedical applications.

Ionic Conductive Organohydrogel With Ultrastretchability, Self-Healable and Freezing-Tolerant Properties for Wearable Strain Sensor.

Currently, stretchable hydrogel has attracted great attention in the field of wearable flexible sensors. However, fabricating flexible hydrogel sensor simultaneously with superstretchability, high mechanical strength, remarkable self-healing ability, excellent anti-freezing and sensing features via a facile method remains a huge challenge. Herein, a fully physically linked poly(hydroxyethyl acrylamide)-gelatin-glycerol-lithium chloride (PHEAA-GE-Gl-LiCl) double network organohydrogel is prepared via a simple one-pot heating-cooling-photopolymerization method. The prepared PHEAA-GE-Gl-LiCl organohydrogel exhibits favorable stretchability (970%) and remarkable self-healing property. Meanwhile, due to the presence of glycerol and LiCl, the PHEAA-GE-Gl-LiCl organohydrogel possesses outstanding anti-freezing capability, it can maintain excellent stretchability (608%) and conductivity (0.102 S/m) even at -40°C. In addition, the PHEAA-GE-Gl-LiCl organohydrogel-based strain sensor is capable of repeatedly and stably detecting and monitoring both large-scale human motions and subtle physiological signals in a wide temperature range (from -40°C to 25°C). More importantly, the PHEAA-GE-Gl-LiCl organohydrogel-based sensor displays excellent strain sensitivity (GF = 13.16 at 500% strain), fast response time (300 ms), and outstanding repeatability. Based on these super characteristics, it is envisioned that PHEAA-GE-Gl-LiCl organohydrogel holds promising potentials as wearable strain sensor.

Preparation and Characterization of Ginger Essential Oil Microcapsule Composite Films.

New food packaging has shown research significance in the face of increasing demand for high-quality foods and growing attention paid to food safety. In this study, ginger essential oil microcapsule composite films were prepared by combining microcapsules prepared by a complex coacervation method with gelatin films, and the mechanical properties and active functions of the composite films were analyzed. Fourier-transform infrared spectroscopy and differential scanning calorimetry confirmed the successful encapsulation of ginger essential oil. The scanning electron microscopy of the composite films showed the microcapsules and gelatin film matrix were highly compatible. During the entire storage period, the antioxidant capacity of the ginger essential oil microcapsule films weakened more slowly than ginger essential oil microcapsules and could be maintained at a relatively high level for a long time. The microcapsule films had excellent inhibitory effects on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. Therefore, the direct addition of microcapsules to a film matrix can broaden the application range of microcapsules and increase the duration of the release of active ingredients. Ginger essential oil microcapsule films are potential biodegradable food packaging films with long-lasting activity.

Ionically Conductive Hydrogel with Fast Self-Recovery and Low Residual Strain as Strain and Pressure Sensors.

Hydrogel-based sensors have attracted enormous interest due to their broad applications in wearable devices. However, existing hydrogel-based sensors cannot integrate satisfying mechanical performances with excellent conductivity to meet the requirements for practical application. Herein, an ionically conductive hydrogel with high strength, fast self-recovery, and low residual strain is constructed through a facile soaking strategy. The proposed ionically conductive double network hydrogel is achieved by combining chemically crosslinked polyacrylamide and physically crosslinked gelatin network followed by sodium citrate solution immersing. The obtained hydrogel has a tensile strength of 1.66 MPa and an elongation of 849%. The ionically conductive hydrogels can be utilized as both strain and pressure sensors with high sensitivity. Moreover, they can be used as ionic skin to monitor various human movements precisely, demonstrating their promising potential in wearable devices and flexible electronics.

Fully physically crosslinked pectin-based hydrogel with high stretchability and toughness for biomedical application.

Hydrogels derived from natural polymers have been extensively investigated in the biomedical field, while inherent brittleness and poor stability limit their applications. In this study, a tough pectin-Fe3+/poly (acrylamide-co-stearyl methacrylate) (P(AAm-co-SMA)) double physical crosslinking (DPC) network hydrogel is prepared using a three-step method. The first HPAAm network is formed via hydrophobic associations among the PSMA segment in P(AAm-co-SMA), and trivalent ions (Fe3+) crosslinked pectin network as the second network. Due to the reversibility of dual physical cross-linking structures, the pectin-Fe3+/HPAAm hydrogel exhibit excellent toughness (1.04-11.20 MJ m-3). In addition, the pectin-Fe3+/HPAAm DPC hydrogels have tunable mechanical properties (tensile strength: 0.97-1.61 MPa, elongation: 133-1346%, elastic modulus: 0.30-2.20 MPa) via adjusting the ratio of pectin network and HPAAm network. To explore their potential application in tissue engineering, ATDC5 chondrocytes were seeded on the prepared DPC hydrogels. Results suggest that the pectin-Fe3+/HPAAm DPC hydrogels can support the adhesion and proliferation of ATDC5, moreover, the ATDC5 cells can penetrate into the hydrogel. It is concluded that the prepared hydrogels exhibit potential application in the load-bearing tissue repair field.

Carbon Nanotubes/Hydrophobically Associated Hydrogels as Ultrastretchable, Highly Sensitive, Stable Strain, and Pressure Sensors.

Conductive hydrogels have become one of the most promising materials for skin-like sensors because of their excellent biocompatibility and mechanical flexibility. However, the limited stretchability, low toughness, and fatigue resistance lead to a narrow sensing region and insufficient durability of the hydrogel-based sensors. In this work, an extremely stretchable, highly tough, and anti-fatigue conductive nanocomposite hydrogel is prepared by integrating hydrophobic carbon nanotubes (CNTs) into hydrophobically associated polyacrylamide (HAPAAm) hydrogel. In this conductive hydrogel, amphiphilic sodium dodecyl sulfate was used to ensure uniform dispersion of CNTs in the hydrogel network, and hydrophobic interactions between the hydrogel matrix and the CNT surface formed, greatly improving the mechanical properties of the hydrogel. The obtained CNTs/HAPAAm hydrogel showed excellent stretchability (ca. 3000%), toughness (3.42 MJ m-3), and great anti-fatigue property. Moreover, it exhibits both high tensile strain sensitivity in the wide strain ranges (gauge factor = 4.32, up to 1000%) and high linear sensitivity (0.127 kPa-1) in a large-pressure region within 0-50 kPa. The CNTs/HAPAAm hydrogel-based sensors can sensitively and stably detect full-range human activities (e.g., elbow rotation, finger bending, swallowing motion, and pronouncing) and handwriting, demonstrating the CNTs/HAPAAm hydrogel's potential as the wearable strain and pressure sensors for flexible devices.

Freezing-Tolerant Supramolecular Organohydrogel with High Toughness, Thermoplasticity, and Healable and Adhesive Properties.

Hydrogels based on supramolecular noncovalent interactions have attracted great research interest but are still limited by relatively low mechanical strength and performance deterioration at subzero temperatures because of the formation of ice crystallization. In this study, an antifreezing and mechanically strong gelatin supramolecular organohydrogel is prepared via a simple strategy of immersing a gelatin pre-hydrogel in the citrate (Cit) water/glycerol mixture solution. In the organohydrogel, a part of water molecules are replaced by glycerol, which inhibits the formation of ice crystallization even at extremely low temperature. In addition, the formation of noncovalent interactions such as the hydrophobic aggregation induced by the salting-out effect, ionic interactions between the -NH3+ of gelatin and Cit3- anions, and hydrogen bonding between gelatin chains and glycerol endows the organohydrogels with high mechanical strength and toughness. The supramolecular organohydrogel can maintain its mechanical flexibility even at -80 °C or be stored for a long time. Moreover, the nature of noncovalent interactions endows the organohydrogel with intriguing thermoplasticity, good healable ability, and excellent adhesive behavior at various substrate surfaces.

Enhanced glucose detection using dendrimer encapsulated gold nanoparticles benefiting from their zwitterionic surface.

The application of ultrasmall gold nanoparticles as enzyme mimics has been drawing great attention. Herein, we developed zwitterionic dendrimer encapsulated gold nanoparticles (Au-G5MC NPs) for highly sensitive and simple colorimetric detection of glucose. Au-G5MC NPs showed peroxidase-like property, which could efficiently catalyze oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color product (oxTMB). This peroxidase-like reaction follows a typical Michaelis-Menten kinetics. The Km towards TMB exhibited a lower value (0.194 mM) than that of horseradish peroxidase (HRP, 0.434 mM). Furthermore, the peroxidase-like properties of Au-G5MC NPs enable colorimetric detection of the concentration of glucose with high selectivity. The linear concentration range of this method was from 14 µM to 166 µM with the detection limit down to 3.8 µM. More importantly, the detection was not interfered by proteins due to the single zwitterionic layer on the Au-G5MC NPs surface. These excellent properties are attributed to the ultrasmall size of gold nanoparticles and high stability of Au-G5MC NPs in complex medium. This catalytic system might have great potential applications for glucose detection in medical diagnostics and biochemistry in the future.

Optimisation extraction of chondroitin sulfate from fish bone by high intensity pulsed electric fields.

High intensity pulsed electric fields (PEF) was used to extract chondroitin sulphate (CS) from fish bone. Results show that PEF extraction speed is much faster, and the content of CS is much higher compared with traditional methods. Variation of PEF parameters and the content of CS were determined by single factor experiments. The processing conditions were optimised by quadratic general rotary unitised design experiments. The maximum yield of 6.92 g/L was achieved under the following conditions: material-liquid ratio of 1:15 g/mL, electric field intensity of 16.88 kV/cm, pulse number of 9, and NaOH concentration of 3.24%. The purity of CS was analysed by agarose gel electrophoresis. CS purity was high, and the extract did not contain any other glycosaminoglycans. PEF can be widely used to extract CS with non-thermal performance, high speed, and low pollution.