Semi-interpenetrating Polymer Network Research Articles

Ecofriendly polysaccharide-based alginate/pluronic F127 semi-IPN hydrogel with magnetic collectability for precise release of pesticides and sustained pest control

Controlled-release systems are crucial for efficient pesticide utilization and environmental protection in agricultural production. The utilization of polysaccharide-based materials derived from biopolymers as carriers for controlling pesticide release holds significant potential. In this work, a reversible near infrared-responsive polysaccharide-based hydrogel (RNPH) was fabricated by employing a semi-interpenetrating polymer network (alginate-FeIII/pluronic F127) as a carrier to encapsulate Fe3O4@polydopamine (FP) and emamectin benzoate (EB)-loaded hollow mesoporous silica. The incorporation of FP into the RNPH introduced a photothermal effect, enabling the precise release of EB through reversible shrinkage of the hydrogel upon NIR irradiation. Additionally, the presence of magnetic Fe3O4 in the system facilitated the rapid removal of remaining RNPH from the environment using a magnet, reducing EB residue. Importantly, RNPH exhibited exceptional controlled-release performance and could be reused for at least 4 cycles. Furthermore, the anti-photolysis ability of EB protected by RNPH was enhanced by 4.8 times compared to EB alone. Moreover, RNPH significantly improved the adhesion of EB to foliar surfaces, thereby reducing the loss of EB while ensuring crop safety. Therefore, the polysaccharide-based hydrogel holds promise as a versatile carrier for the precise release of EB, offering valuable applications in enhancing pesticide bioavailability and promoting environmental safety.

Effective removal of antibiotic resistance genes from wastewater using marine waste-derived novel nanocomposites

Wastewater (WW) has been identified as a major hotspot of microbial emerging contaminants (MECs), such as antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Currently used WW treatment methods cannot efficiently eliminate these pollutants, resulting in passive contamination of adjacent environments receiving undertreated discharge. More effective WW treatment strategies are therefore urgently required. In this study, newly developed and well-characterised semi-interpenetrating polymer network (semi-IPN) hydrogels derived from the valorisation of marine wastes (e.g., shrimp shells) were investigated for their ARG removal potential. The results indicated that multiple ARGs prevalent in WW, such as ermB, qrnS, sul1 and tetO, were removed by up to 100% after being treated by novel hydrogels. In terms of horizontal gene transfer-associated genetic elements, such as integron-1 intl1, transposons tnpA1 (IS4 group) and tnpA2 (IS6 group), substantial reduction approaching 99.9% was also achieved. Moreover, up to 97% of efflux pump-associated qacEΔ1 conferring multidrug resistance (MR) was successfully attenuated. To conclude, the semi-INP hydrogels developed exhibited great potential for ARG mitigation towards strengthening WW decontamination, which provides a viable, cost-effective and environmentally friendly novel treatment approach.

Semi-Interpenetrating Network Anion Exchange Membranes by Thiol-Ene Coupling Reaction for Alkaline Fuel Cells and Water Electrolyzers.

In this work, a thiol-ene coupling reaction was employed to prepare the semi-interpenetrating polymer network AEMs. The obtained QP-1/2 membrane exhibits high hydroxide conductivity (162.5 mS cm-1 at 80 °C) with a relatively lower swelling ratio, demonstrating its mechanical strength of 42 MPa. This membrane is noteworthy for its improved alkaline stability, as the semi-interpenetrating network effectively limits the attack of hydroxide. Even after being treated in 2 M NaOH at 80 °C for 600 h, 82.5% of the hydroxide conductivity is maintained. The H2/O2 fuel cell with QP-1/2 membrane displays a peak power density of 521 mW cm-2. Alkaline water electrolyzers based on QP-1/2 membrane demonstrated a current density of 1460 mA cm-2 at a cell voltage of 2.00 V using NiCoFe catalysts in the anode. All the results demonstrate that a semi-interpenetrating structure is a promising way to enhance the mechanical property, ionic conductivity, and alkaline stability of AEMs for the application of alkaline fuel cells and water electrolyzers.

Skin-adhesive lignin-grafted-polyacrylamide/hydroxypropyl cellulose hydrogel sensor for real-time cervical spine bending monitoring in human-machine Interface

Developing a straightforward method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, and biocompatibility remains a significant challenge. While current approaches aim to enhance mechanical performance, they often require additional steps or external forces for fixation, leading to increased production time and limited practicality. A novel lignin-grafted polyacrylamide/hydroxypropyl cellulose hydrogel (L-g-PAM/HPC hydrogel) with a semi-interpenetrating polymer network structure had been developed in this research that boasted exceptional adhesion to the skin (∼68 kPa) and stretchability properties (∼1637 %) compared to PAM-based hydrogels. By incorporating conductive additives such as silver nanowires and carbon nanocages to construct a bridge-like structure within the hydrogel matrix, the resulting AgC@L-g-PAM/HPC hydrogel exhibited impressive electrical conductivity, surpassing that of other PAM-based hydrogels relying on MXene, with a maximum value of 0.76 S/m. Furthermore, the AgC@L-g-PAM/HPC hydrogel retained its efficient electrical signal transmission capability even under mechanical stress. These make it an ideal flexible strain sensor capable of detecting various human motions. In this study, a smart real-time monitoring system was successfully developed for tracking cervical spine bending, serving as an extension for monitoring human activities.

Novel biodegradable nanocomposite hydrogels based on biopolymers and various montmorillonite contents as high-strength coating membranes for efficient slow-release fertilizers

Slow-release fertilizers (SRF) have emerged as a sustainable remedy to the environmental problems caused by conventional water-soluble fertilizers. They have demonstrated their efficacy in reducing fertilizer dosage applications, enhancing fertilizer utilization efficiency, minimizing losses, and ultimately improving crop yield. This study developed biodegradable nanocomposite hydrogels (BHM) as a promising approach by combining cassava starch (Cst), polyacrylamide (PAM), natural rubber (NR), and various montmorillonite (MMT) contents (0–10 wt%) and fabricating via free-radical polymerization and semi-interpenetrating polymer network technology, crosslinked by glutaraldehyde. Notably, the addition of MMT played a crucial role and significantly improved the tensile strength, biodegradability, and N release efficiency of the BHM hydrogels. BHM3 (3 wt% MMT) demonstrated the highest swelling ratio of 7074% and improved N release efficiency, mechanical strength, and biodegradation rate by 39.1%, 260% and 58%, respectively, compared to BHM0. The FWBHM formulations (urea coated with BHM and wax layers) also exhibited good biosafety. Finally, FWBHM3 yielded acceptable growth rates, a greater yield, and a 4-fold lower price than commercial SRF. These findings provide a promising route for developing new nanocomposite hydrogels based on Cst, NR, and MMT components with high swelling and water-retention, high strengths, and excellent biodegradation with greater slow-release duration and sustained environments.

Polyvinyl alcohol composite hydrogels/epoxidized natural rubber composites (CMCS/PVA/CS-ENR) with core-shell structure as biomass coating material for slow-release nitrogen fertilizer

Using natural rubber (NR)/chitosan (CS)/polyvinyl alcohol (PVA) as raw materials, biodegradable semi-IPN (semi-interpenetrating polymer network) composites were prepared by thiol-epoxy click reaction under UV light, which was used as the shell of sustained release preparation. Using polyvinyl alcohol (PVA)/carboxymethyl chitosan (CMCS) as raw material and vanillin as the cross-linking agent, hydrogen-bonded hybrid network hydrogel loaded with urea was prepared by freeze-thaw cycle, which was used as the core of sustained-release preparation. Finally, a green-coated urea fertilizer with core-shell structure was prepared to ameliorate the environmental pollution of slow-release fertilizer (for example, synthetic polymer-coated fertilizers are difficult to biodegrade), as well as to achieve the water retention and the effective slow-release. The high CS/PVA contents and the combination of the hydrogel core and the rubber shell significantly improved the mechanical properties of the coating material (tensile strength above 5 MPa, elongation at break up to 1400 %), hydrophilicity (to promote the degradation rate of the rubber shell) and soil water retention of the coating material (close to pure hydrogel), showing enhanced reaction. In terms of slow-release effect, coated nitrogen fertilizer with 3 % CS content, 5 % PVA content and 10-min coating time (SRP3/10) achieved the best slow-release effect of nitrogen (N) in water (62.7 % at 10 days), which was related to the hydrophilicity, semi-IPN skeleton and the cross-linking structure of the network, and the release conformed to the Korsmeyer-Peppas model with a non-Fickian diffusion release mechanism, indicating that the behavior of N release was mediated by a combination of drug diffusion and skeleton dissolution.

Electrospun Poly(vinyl alcohol)-Based Conductive Semi-interpenetrating Polymer Network Fibrous Hydrogel: A Toolbox for Optimal Cross-Linking

Cross-linking of poly(vinyl alcohol) (PVA) creates a three-dimensional network by bonding adjacent polymer chains. The cross-linked structure, upon immersion in water, turns into a hydrogel, which exhibits unique absorption properties due to the presence of hydrophilic groups within the PVA polymer chains and, simultaneously, ceases to be soluble in water. The properties of PVA can be adjusted by chemical modification or blending with other substances, such as polymers, e.g., conductive poly[3-(potassium-5-butanoate)thiophene-2,5-diyl] (P3KBT). In this work, PVA-based conductive semi-interpenetrating polymer networks (semi-IPNs) are successfully fabricated. The systems are obtained as a result of electrospinning of PVA/P3KBT precursor solutions with different polymer concentrations and then cross-linking using “green”, environmentally safe methods. One approach consists of thermal treatment (H), while the second approach combines stabilization with ethanol and heating (E). The comprehensive characterization allows to evaluate the correlation between the cross-linking methods and properties of nanofibrous hydrogels. While both methods are successful, the cross-linking density is higher in the thermally cross-linked samples, resulting in lower conductivity and swelling ratio compared to the E-treated samples. Moreover, the H-cross-linked systems have better mechanical properties─lower stiffness and greater tensile strength. All the tested systems are biocompatible, and interestingly, due to the presence of P3KBT, they show photoresponsivity to solar radiation generated by the simulator. The results indicate that both methods of PVA cross-linking are highly effective and can be applied to a specific system depending on the target, e.g., biomedical or electronic applications.

Enhancing selective transformation of benzyl alcohol by interface catalysis of a bilayer composite membrane

Facile and environment-friendly preparation of chloride-free benzaldehyde is still a great challenge in industry. Herein, a novel bilayer composite membrane with a top semi-interpenetrating polymer network layer and a lower polyvinylidene fluoride/poly (methacrylic acid) @Pd catalytic layer was prepared for the green preparation of chloride-free benzaldehyde. Results indicated that when the composite membrane was placed between the interface of H2O2/water solution and benzyl alcohol/toluene solution, it could efficiently and conveniently catalyze the oxidation of benzyl alcohol by hydrogen peroxide into chloride-free benzaldehyde. Furthermore, the oil phase and water phase were always separated by the bilayer membrane during the whole process and thus the reaction was operated conveniently. The good result was attributed to the unique structure of the bilayer membrane and the interface reaction technique. Undoubtedly, coupling the bilayer membrane with the interface reaction technique is a new and effective strategy for the green preparation of chloride-free benzaldehyde.

Siloxane-type single-ion conductors enable composite solid polymer electrolyte membranes with fast Li+ transporting networks for dendrite-proof lithium-metal batteries

Solid polymer electrolytes (SPEs) significantly improve the operational safety of lithium-metal batteries (LMBs) by replacing the flammable liquid electrolytes, but still suffer from key limitations including low ionic conductivities, inferior lithium-ion transference numbers (tLi+), and poor mechanical properties. Herein, a novel poly (ethylene oxide) (PEO)-based composite electrolyte, with a semi-interpenetrating polymer network, is fabricated via in-situ cross-linking siloxane-type single-ion conductors (SICs) in PEO SPEs by one-step sol–gel method, enabling they simultaneously achieve the enhanced electrochemical and physicochemical properties. Incorporating a thermodynamically compatible SIC network not only reduces the crystallization of PEO matrix while facilitating the segmental relaxation of polymer chains, but also contributes to dissociating Li-salt and forming a three-dimensional conducting network for fast Li-ion transport. Thus, the resulting composite SPEs exhibit higher ionic conductivities (1.10 × 10−5 S cm−1 at 25 °C and 1.41 × 10−4 S cm−1 at 60 °C), tLi+ (0.52), and electrochemical window stability (4. 59 V) than pure PEO SPEs. Furthermore, this stable SIC networks can also enhance the mechanical performance and thermal stability of the composite SPEs. Thanks to these merits, the composite SPEs show the significant feasibility to regulate Li deposition and suppress the growth of Li dendrites, affording excellent stability and compatibility with Li metal. As a result, the Li/Li symmetrical cells using the composite SPEs show excellent cycling performances without an evident polarization enlargement for more than 900 h. The LiFePO4/Li batteries also achieve a remarkable capacity of 132.8 mA g−1 at 1C and exhibit impressive cycling abilities with 91.9% retention over 250 cycles. This study provides a promising concept for developing advanced composite SPEs for potential application in solid-state dendrite-free LMBs.

Temperature‐Optimized Synthesis of SiO2‐Reinforced N‐(Alkyl)Acrylamide‐Based Semi‐IPN Hybrid Gels Functionalized with Methacrylic Acid Units

Front Cover: In article number 2300006, Nermin Orakdogen and co-workers deal with temperature-optimized synthesis of N-(alkyl)acrylamide-based semi-interpenetrating polymer network reinforced with silica nanoparticles and functionalized with methacrylic acid units by varying the polymerization temperature. The gelation is performed at different temperatures to evaluate the formation mechanism. The mechanical properties, swelling properties and susceptibility to stimuli show a wide dependence on the polymerization temperature.

Sponge-like, semi-interpenetrating self-sensory hydrogel for smart photothermal-responsive soft actuator with biomimetic self-diagnostic intelligence

Actuators based on hydrogels are good candidates for biomimetic soft robots due to their excellent mechanical properties and flexibility. Despite great efforts in hydrogel-based actuators, their actuation process still differs from the “recognition-judgment-execution” process that conscious intelligent beings go through owing to the lack of perceptive capacity. Herein, to imitate the intelligent actuation process of conscious organisms, a fast photo-thermal responsive and self-sensory soft actuator is proposed based on sponge-like hydrogel with semi-interpenetrating (semi-IPN) polymer network of thermosensitive poly (N-isopropylacrylamide) (PNIPAM) and electronically conductive polyaniline (PANI). The proposed actuator exhibits excellent photo-thermal responsiveness enabling remotely triggered actuation controlled by near infrared light (NIR), covering all azimuths with ultrafast response rate (within 2 s) and recover rate (within 1 s). Meanwhile, the conformational transition of PNIPAM networks during the course of actuation also lead to accompanying migration of the interpenetrated PANI chains and significant variation of local conductivity (>15%), endowing the actuator with self-sensing capacity to monitor its deformations. Eventually, a smart self-adaptive actuator is designed inspired by neuromuscular in intelligent organisms, which can actively perceive external environmental stimuli and consciously regulate its own shape transformation by monitoring and analyzing electrical signal. This sensory actuating hydrogel can provide insights into the development of artificial intelligent soft robotics with higher levels of autonomy and complexity.

Development and evaluation of pH sensitive semi-interpenetrating networks: assessing the impact of itaconic acid and aloe vera on network swelling and cetirizine release.

Hydrogels are crosslinked three-dimensional networks, and their properties can be easily tuned to target the various segments of the gastrointestinal tract (GIT). Cetirizine HCl (CTZ HCl) is an antihistaminic drug, which when given orally can upset the stomach. Moreover, this molecule has shown maximum absorption in the intestine. To address these issues, we developed a pH-responsive semi-interpenetrating polymer network (semi-IPN) for the delivery of CTZ HCl to the lower part of the GIT. Initially, 10 different formulations of itaconic acid-grafted-poly (acrylamide)/aloe vera [IA-g-poly (AAm)/aloe vera] semi-IPN were developed by varying the concentration of IA and aloe vera using the free radical polymerization technique. Based on swelling and sol-gel analysis, formulation F5 containing 0.3%w/w aloe vera and 6%w/w IA was chosen as the optimum formulation. The solid-state characterization of the optimized formulation (F5) revealed a successful incorporation of CTZ HCl in semi-IPN without any drug-destabilizing interaction. The in vitro drug release from F5 showed limited release in acidic media followed by a controlled release in the intestinal environment for over 72h. Furthermore, during the in vivo evaluation, formulation F5 did not affect the hematological parameters, kidney, and liver functions. Clinical observations did not reveal any signs of illness in rabbits treated with hydrogels. Histopathological images of vital organs of treated animals showed normal cellular architecture. Thus, the results suggest a non-toxic nature and overall potential of the developed formulation as a targeted drug carrier.

Adsorption of Copper and Arsenic from Water Using a Semi-Interpenetrating Polymer Network Based on Alginate and Chitosan.

New biobased hydrogels were prepared via a semi-interpenetrating polymer network (semi-IPN) using polyacrylamide/chitosan (PAAM/chitosan) hydrogel for the adsorption of As(V) or poly acrylic acid/alginate (PAA/alginate) hydrogel for the adsorption of Cu(II). Both systems were crosslinked using N,N'-methylenebisacrylamide as the crosslinker and ammonium persulfate as the initiating agent. The hydrogels were characterized by SEM, Z-potential, and FTIR. Their performance was studied under different variables, such as the biopolymer effect, adsorbent dose, pH, contact time, and concentration of metal ions. The characterization of hydrogels revealed the morphology of the material, with and without biopolymers. In both cases, the added biopolymer provided porosity and cavities' formation, which improved the removal capacity. The Z-potential informed the surface charge of hydrogels, and the addition of biopolymers modified it, which explains the further metal removal ability. The FTIR spectra showed the functional groups of the hydrogels, confirming its chemical structure. In addition, the adsorption results showed that PAAM/chitosan can efficiently remove arsenic, reaching a capacity of 17.8 mg/g at pH 5.0, and it can also be regenerated by HNO3 for six cycles. On the other hand, copper-ion absorption was studied on PAA/alginate, which can remove with an adsorption capacity of 63.59 mg/g at pH 4.0, and the results indicate that it can also be regenerated by HNO3 for five cycles.

Hierarchically porous hydrogel electrolyte prepared from interpenetrating polymer networks for flexible Zn-Air batteries

Gel polymer electrolyte (GPE) based flexible zinc-air batteries (ZABs) are considered promising power sources for next-generation wearable devices because of their high specific energy density, low cost, high safety, and environmental friendliness. However, the liquid component in GPE is susceptible to evaporation through the air cathode, drastically reducing the cell performance and lifetime. Poly(vinyl alcohol) (PVA) is the most widely adopted ion conductive polymer, but its poor water retention and low ionic conductivity hinder the widespread commercialization of flexible ZABs. A hierarchically porous (HP) PVA and poly(acrylic acid) (PAA) hybrid GPE is developed to address the aforementioned issues. The polymerization of acrylic acid in a PVA matrix forms a semi-interpenetrating polymer network involving a unique HP structure inside the membrane. The PAA-rich lotus-seed-like pores fundamentally improve electrolyte uptake and retention properties, and enhance ionic conductivity. The HP-PVA/PAA hybrid GPE delivers excellent cycling stability, rate characteristics, and power output in ZABs. Furthermore, HP-PVA/PAA based flexible ZABs incorporated into the customized strap demonstrates their feasibility for powering the wearable smart watch.

Resorbable membrane design: In vitro characterization of silver doped-hydroxyapatite-reinforced XG/PEI semi-IPN composite

In this study, the production and characterization of silver-doped hydroxyapatite (AgHA) reinforced Xanthan gum (XG) and Polyethyleneimine (PEI) reinforced semi-interpenetrating polymer network (IPN) biocomposite, known to be used as bone cover material for therapeutic purposes in bone tissue, were performed. XG/PEI IPN films containing 2AgHA nanoparticles were produced by simultaneous condensation and ionic gelation. Characteristics of 2AgHA-XG/PEI nanocomposite film were evaluated by structural, morphological (SEM, XRD, FT-IR, TGA, TM, and Raman) and biological activity analysis (degradation, MTT, genotoxicity, and antimicrobial activity) techniques. In the physicochemical characterization, it was determined that 2AgHA nanoparticles were homogeneously dispersed in the XG/PEI-IPN membrane at high concentration and the thermal and mechanical stability of the formed film were high. The nanocomposites showed high antibacterial activity against Acinetobacter Baumannii (A.Baumannii), Staphylococcus aureus (S.aureus), and Streptococcus mutans (S.mutans). L929 exhibited good biocompatibility for fibroblast cells and was determined to support the formation of MCC cells. It was shown that a resorbable 2AgHA-XG/PEI composite material was obtained with a high degradation rate and 64% loss of mass at the end of the 7th day. Physico-chemically developed biocompatible and biodegradable XG-2AgHA/PEI nanocomposite semi-IPN films possessed an important potential for the treatment of defects in bone tissue as an easily applicable bone cover. Besides, it was noted that 2AgHA-XG/PEI biocomposite could increase cell viability, especially in dental-bone treatments for coating, filling, and occlusion.

Smart hydrogels based on semi-interpenetrating polymeric networks of collagen-polyurethane-alginate for soft/hard tissue healing, drug delivery devices, and anticancer therapies.

In this work, hydrogels based on semi-interpenetrating polymeric networks (semi-IPN) based on collagen-polyurethane-alginate were studied physicochemically and from different approaches for biomedical application. It was determined that the matrices in the hydrogel state are crosslinked by the formation of urea and amide bonds between the biopolymer chains and the polyurethane crosslinker. The increment in alginate content (0-40 wt%) significantly increases the swelling capacity, generating semi-crystalline granular structures with improved storage modulus and resistance to thermal, hydrolytic, and proteolytic degradation. The in vitro bioactivity results indicated that the composition of these novel hydrogels stimulates the metabolic activity of monocytes and fibroblasts, benefiting their proliferation; while in cancer cell lines, it was determined that the composition of these biomaterials decreases the metabolic activity of breast cancer cells after 48 h of stimulation, and for colon cancer cells their metabolic activity decreases after 72 h of contact for the hydrogel with 40 wt% alginate. The matrices show a behavior of multidose release of ketorolac, and a higher concentration of analgesic is released in the semi-IPN matrix. The inhibition capacity of Escherichia coli is higher if the polysaccharide concentration is low (10 wt%). The in vitro wound closure test (scratch test) results indicate that the hydrogel with 20 wt% alginate shows an improvement in wound closure at 15 days of contact. Finally, the bioactivity of mineralization was evaluated to demonstrate that these hydrogels can induce the formation of carbonated apatite on their surface. The engineered hydrogels show biomedical multifunctionality and they could be applied in soft and hard tissue healing strategies, anticancer therapies, and drug release devices.

Effect of Composition of Lung Biomimetic Niche on the Mesenchymal Stem Cell Differentiation toward Alveolar Type II Pneumocytes.

Pulmonary niche dynamically orchestrates the signals, such as proliferation or differentiation of mesenchymal stem cells (MSCs), which allows inducing tissue repair. Lung niche includes extracellular matrix (ECM), comprising hyaluronic acid (HA) and collagen (COLL), and several types of MSCs. Impaired ECM, in lung pathologies, makes the promising therapies based on MSCs ineffective, as it results in a reduced attachment and homing of MSCs, precluding their differentiation and viability. To overcome this problem, in this study a pulmonary biomimetic niche based on HA and COLL hydrogel is developed, with the specific aim to elucidate the role of COLL and HA/COLL semi-interpenetrating polymer networks (SIPNs) in directing the differentiation of MSCs into Alveolar Type II (ATII) cells. The effect of low (L), medium (M), and high (H) molecular weight (MW) HA is investigated, both like structural component of the SIPNs hydrogel and like trophic factor in cell culture media solution. HA in the culture media significantly improves surfactant protein (SP)-C expression (≈2ng mL-1 ), without showing difference in the MW tested, compared to control only (≈1ng mL-1 ). Furthermore, LMWHA/COLL hydrogel promotes the SPC expression (approximately two times) compared to COLL, MMWHA/COLL, and HMWHA/COLL hydrogels.

Smart collagen/xanthan gum-based hydrogels with antibacterial effect, drug release capacity and excellent performance in vitro bioactivity for wound healing application

The design of hydrogels based on natural polymers that have modulation of antibacterial capacity, ideal performance in release capacity of encapsulated drugs, and desired bioactivity for applications in wound healing represents a modern trend in biomaterials. In this work, novel hydrogels of semi-interpenetrating polymeric networks based on collagen and xanthan gum (XG) were investigated. The linear chains of XG can semi-interpenetrate inside to matrix of crosslinked collagen with polyurethane under physiological conditions, generating amorphous surfaces with fibrillar-granular reliefs that have accelerated gelation time (about 15 min), super water absorption (up to 3100%) and high inhibition capacity of pathogenic bacteria such as Escherichia coli (up to 100% compared to amoxicillin at 20 ppm). The increment of XG in the hydrogel (up to 20 wt.%) allows for improvement in the storage module, resistance to thermal degradation, slow the rate of hydrolytic and proteolytic degradation, allowing to encapsulate and controlled release of molecules such as ketorolac and methylene blue; besides, it shows to keep the metabolic activity of fibroblasts and monocytes at 48 h of evaluation, without observing cytotoxic effects. The bioactivity of these hydrogels is improved since they have excellent hemocompatibility and enhanced cell proliferation. Specifically, the hydrogel with 20 wt.% of XG shows to decrease the production of tumor necrosis factor-α and CCL-2 cytokines, increasing the production of transforming growth factor-β in human monocytes, which could be used to modulate inflammation and regenerative capacity in wound healing strategies.

A pH and Temperature Dual-Responsive Microgel-Embedded, Adhesive, and Tough Hydrogel for Drug Delivery and Wound Healing

Stimuli-responsive hydrogels have attracted much attention over the past decade for potential bioengineering applications such as wound dressing and drug delivery. In this work, a pH and temperature dual-responsive microgel-embedded hydrogel has been fabricated by incorporating poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAAm-co-AAc) based microgel particles into polyacrylamide (PAAm)/chitosan (CS) semi-interpenetrating polymer network (semi-IPN), denoted as microgel@PAM/CS. The resultant hydrogel possesses excellent mechanical properties including stretchability, compressibility, and elasticity. In addition, the microgel@PAM/CS hydrogels can tightly adhere to the surfaces of a variety of tissues such as porcine skin, kidney, intestine, liver, and heart. Moreover, it shows controlled dual-drug release profile of both bovine serum albumin (BSA) (as a model protein) and sulfamethoxazole (SMZ), an antibiotic. Excellent antimicrobial properties are obtained for SMZ-loaded microgel@PAM/CS hydrogels. Compared with traditional drug administration methods such as by mouth, injection, and inhalation, the microgel@PAM/CS hydrogels possess advantages such as higher drug loading efficiency (by more than 80%) and controllable and sustained (over 48 h) release. The microgel@PAM/CS hydrogels can significantly enhance the wound healing process. This work provides a facile approach for the fabrication of multifunctional stimuli-responsive microparticle-embedded hydrogels with semi-IPN structures, and the as-prepared microgel@PAM/CS hydrogels have great potential for applications as smart wound dressing materials in biomedical engineering.

Polyethylene ceramic separators with semi-interpenetrating polymer network boosting fast-charging cycle capacity retention and safety for lithium-ion batteries

Fast-charging lithium-ion batteries (LIBs) have recently received significant attention. In current commercial LIBs, lithium precipitation frequently occurs under long-term cycling and fast-charging conditions, adversely affecting their cycle capacity retention and safety. The primary cause of lithium precipitation is electrolyte loss during long-term cycling. In this study, a thermoplastic polyurethane/polyurethane acrylate semi-interpenetrating polymer network ceramic separator with high electrolyte retention (200%) and interfacial adhesion (6.6 N) is prepared and without a decrease in the energy density. The LiNi0.8Mn0.1Co0.1O2/graphite batteries fabricated with this separator show excellent electrochemistry properties (300 cycles, 1.5 C, discharge capacity of 3677 mAh, capacity retention of 93%). Furthermore, this study presents a novel strategy to mitigate the issue of lithium precipitation in fast-charging LIBs. Therefore, this functional separator is a promising alternative for the conventional commercial polyvinylidene difluoride separators and provides a new avenue for developing the next generation of fast-charging devices.