Polyvinyl Alcohol Research Articles

Incorporation of polyvinyl alcohol in bacterial cellulose/polypyrrole flexible conductive films to enhance the mechanical and conductive performance

The integration of polypyrrole (PPy) into bacterial cellulose (BC) has provided significant conductivity and cost benefits. However, this combination has led to a reduction in mechanical properties, particularly in terms of elongation at break and tensile strength. This study investigated the enhancement of BC/PPy composite films by incorporating polyvinyl alcohol (PVA). The resulting BC/PPy/PVA films demonstrated improvements in flexibility, tensile strength and thermal stability. Specifically, with 7 % PVA, the flexible films exhibited remarkable enhancements: tensile strength increased from 11.01 MPa (for BC/PPy) to 25.27 MPa and elongation at break rose from 5.81 % to 11.54 %. Additionally, the electrical conductivity of the BC/PPy/PVA films with a resistance of 38.5 Ω, surpassed that of the BC/PPy films. Furthermore, the equilibrium swelling water absorption rates of BC/PPy and BC/PPy/PVA films were 30.6 % and 81.4 %, respectively, with corresponding resistances of 530 Ω and 540 Ω. The variation in resistance between the dry and swollen states of the BC/PPy/PVA flexible conductive film resulted in differences in the brightness of the small light bulb. These findings highlighted the synergistic effects of PVA within the BC/PPy matrix, presenting a promising avenue for developing high-performance conductive materials suitable for flexible electronics and wearable devices.

The rational design of ratiometric probe based on fluorescence carbon dots and its PVA film platform for the detection of Hg2+: tunable mechanism and the performance

Carbon dots (CDs) are recognized as sensitive probes for the detection of Hg2+ due to their remarkable fluorescent properties and ease of synthesis. However, drawbacks such as high costs, intricate synthesis, and non-portability hinder their broader applications. This study reported the synthesis of tunable multicolor CDs, including blue (B-CDs), green (G-CDs), and orange (O-CDs), by using hydrothermal methods while adjusting precursors and temperature. The observed fluorescence redshift from B-CDs to G-CDs or O-CDs arose from interactions among particle size, sp² conjugation, and surface oxidation, while the redshift from G-CDs to O-CDs was linked to surface fluorophores. Moreover, a ratiometric probe was developed by mixing B-CDs (response signal) and O-CDs (reference signal). Hg2+ significantly quenched B-CDs fluorescence due to static quenching from electron transfer. The probe demonstrated excellent stability and sensitivity, with limits of detection (LOD) of 4.8nM in the 0-0.6μM range and 9.2nM in a broader range (0-50μM). A portable smartphone-assisted detection platform was further developed by integrating the probe into polyvinyl alcohol (PVA) hydrogel. Both methods manifested the capability to accurately quantify Hg2+ in real water samples. This research provides innovative strategies for multicolor CDs and a sensing platform for rapid on-site Hg2+ detection.

Azelaic acid-based lyotropic liquid crystals gel for acne vulgaris: Formulation optimization, antimicrobial activity and dermatopharmacokinetic study

The proposed study aimed to develop a topical gel containing azelaic acid (AZA)-based lyotropic liquid crystals (LLCs) for the treatment of acne vulgaris. AZA-based LLCs were optimized by varying Poloxamer-407 and polyvinyl alcohol concentration using a central composite design, which showed that both independent variables had a significant effect on the formulation. The highest desirable trial of AZA-based LLCs (Batch-7) containing 300 mg poloxamer-407 and 100 mg polyvinyl alcohol depicted the particle size, zeta potential, and entrapment efficiency of 184.2 nm, −16.1 mV, and 79.96 %, respectively. TEM images confirmed the globular vesicles of LLCs, and ATR-FTIR and DSC results confirmed the compatibility of formulation excipients. In vitro, the release of AZA, AZA-based LLCs, AZA-based LLC gel, and marketed gel showed a release of 23.29, 95.24, 91.07 and 59.88 %, respectively, after 24 h in phosphate buffer pH 6.8. Ex vivo release of AZA-based LLC gel displayed an 86.56 % release after 24 h. The antimicrobial activity of AZA-based LLC gel exhibited a comparable efficacy with marketed gel against Cutibacterium acnes, Staphylococcus epidermis and Staphylococcus aureus. The acute dermal irritation study indicated excellent safety and skin compatibility of AZA-based LLC gel without any erythema and edema. The dermatopharmacokinetic study displayed an enhanced drug retention for AZA-based LLC gel (146.121 ± 21.13 µg/cm2) than marketed gel (58.58 ± 15.95 µg/cm2) in the dermal layer, which would improve its therapeutic effect. These outcomes proved that AZA-based LLC gel has the potential to enhance skin penetration and retention for effective management of acne vulgaris.

Cubosomes hydrogel containing silver based organometallic compounds for enhanced wound healing of burns: In vitro and in vivo studies

The aim of this study is to investigate the treatment of burn wounds and bacterial infections, specifically focusing on silver(I) N-heterocyclic carbene (Ag-NHC) loaded into cubosomes. Ag-NHC is an organometallic complex of silver (Ag) and can be considered an active pharmaceutical ingredient for the topical treatment of burns. A novel nanoparticle system, cubosome dispersions, was formulated using high pressure homogenization methods with different concentrations of lipid phase glyceryl monooleate (GMO), surfactants such as poloxamer 407 (F-127), and polyvinyl alcohol (PVA). The optimized formulation (U6) was characterized by in vitro drug release profile (90.54 ± 1.17 %), particle size (126.7 ± 0.98 nm), zeta potential (−21.6 ± 6.83 mV), entrapment efficiency (89.30 ± 1.46 %), and morphology as observed by transmission electron microscopy (TEM). The U6 formulation was incorporated into a hydrogel containing Carbopol 940 to form a cubosomal hydrogel (cubogel). The cubogel was characterized by the in vitro release of Ag-NHC (92 %), entrapment efficiency (>90 %), pH (5.3), viscosity (1.2 cP), spreadability, and TEM. From the in vitro drug release pattern, it was concluded that the U6 formulation showed slow and sustained drug release over 24 h, and demonstrated superior burn healing compared to marketed products. The in vivo wound healing study revealed that the cubogel demonstrated a superior burn healing rate compared to commercially available products (Quench® and Clotrimazole®). The in vivo histopathological results showed that the prepared cubogel was effective in treating second-degree burns, with no side effects or skin irritation, compared to commercial products. Additionally, Ag-NHC-loaded cubogel facilitated sustained release for treating burn wounds without any bacterial infections. The current findings provide a strong basis for the initiating phase 0 clinal trials, highlighting significant potential for the further research to benefit the pharmaceutical industry.

A recyclable, toughening, extreme-condition resistant flame retardant for unsaturated polyester: Bridging performance and sustainability

Recycling thermosets presents significant economic benefits and social implications, and to date, a series of controllable recycling strategies have been proposed. However, prior research has primarily focused on neat polymers, neglecting the impact of the recycling process on composites whose additives may lose performance post-recycling. The paradigm shift towards sustainability necessitates the development of additives that not only exhibit high performance but also endure recycling conditions. Herein, taking flame-retardant unsaturated polyester (FRUP) as an example, we designed a new flame retardant (DPPONSi) with multiple flame-retardant elements and a low phosphorous oxidation state. FRUP with 16.7 wt% of DPPONSi achieves a V-0 rating in the UL-94 vertical burning test, and its limiting oxygen index (LOI) reaches 27.1%. Moreover, its peak heat release rate and total heat release are distinctively reduced by 65% and 42%, respectively. The high flame-retardant efficiency structure also protected DPPONSi from by-reactions. Without complex separation processes, FRUP degradation products were integrated with polyvinyl alcohol (PVA) to create flame-retardant aerogels with high flame retardancy. Additionally, we systematically studied the influence of flame retardants with varying oxidation states on FRUP, the corresponding flame-retardant mechanisms, and the degradation process of FRUP. This work realizes the organic combination of strategies to enhance the high efficiency of flame retardants with design methods for flame retardants that are resistant to existing unsaturated polyester degradation systems.

Development of an intelligent packaging material incorporating betacyanin from red beetroot extract into polyvinyl alcohol films

This research aimed to develop an intelligent packaging material by incorporating betacyanin from red beetroot extract into polyvinyl alcohol (PVA) film. Betacyanin was extracted using three solvents (Distilled Water, Ethanol, and Methanol), and films were prepared. The methanolic extract had the highest betacyanin content (416.57µg/100g), while the distilled water extract had the lowest (310.22µg/100g). Incorporating betacyanin increased the film thickness, with methanol-extracted films (MEF) being the thickest (126.36µm). Light transmittance differed significantly, being highest in ethanol-extracted films (EEF) (4.32%) compared to control (3.65%) and MEF (3.82%). Water solubility was highest in the control sample (44.94%), and water vapor permeability was lowest in methanol-extracted films (14.25gmsPa-1 × 10-7), indicating better film quality. MEF had the lowest lightness (L*=31.71), while control films had the highest (L*=38.84). The a* value was lowest for control films (a*=1.97) and highest for methanol-extracted films (a*=6.08). EEF had the highest b* value (b*=6.58±0.95), and control films had the lowest (b*=4.01). All films exhibited low mechanical resistance with tensile strengths ranging from 2.84 to 3.16 MPa. Additionally, these films can detect pH changes, acting as promising colorimetric bioindicators. The study concludes that intelligent films made with methanol-extracted betacyanin are viable for developing pH-responsive packaging for the food industry.

Developing novel hybrid bilayer nanofibers based on polylactic acid with impregnation of chamomile essential oil and gallic acid-stabilized silver nanoparticles

This study presents fabrication and characterization of novel chamomile essential oil (CMO)/gallic acid-stabilized silver nanoparticles (gallic acid-nanosilver, GNS), embedded into polylactic acid (PLA)-based hybrid bilayer nanofibers (NFs). Where CMO was impregnated into polyvinyl alcohol (PVA)-polyethylene glycol (PEG) solution and electrospun simultaneously with PLA to obtain PLA/PVA-PEG-CMO NFs (PLA/CMO A2). Meanwhile, GNS were added to PVA-PEG-CMO and electrospun to obtain PLA/PVA-PEG-CMO-GNS NFs (PLA/CMO-GNS A3). Where pure PLA/PVA-PEG NFs were coded pure PLA/A1. Physicochemical properties of fabricated bilayer-NFs were performed using various approaches. Besides, porosity%, swelling, biodegradability, CMO release pattern, antioxidant, antibacterial activity and cytotoxicity were investigated. Study investigation revealed PLA-based bilayer NFs exhibited a biphasic release profile for impregnated CMO. Due to presence of GA, antioxidant property and biocompatibility of PLA/CMO-GNS A3 was superior compared to pure PLA/A1 and PLA/CMO A2. Antibacterial activity was enhanced in presence of CMO in PLA/CMO A2 than pure PLA/A1. Furthermore, addition of GNS in PLA/CMO-GNS A3 displayed highest antibacterial activity due to synergy of CMO/GNS. Finally, MTT assay with HFB4 fibroblasts demonstrated absence of cytotoxicity of bilayer-based NFs. Thus, study suggests that developed PLA/PVA-PEG NFs could be a promising candidate for tissue regeneration and food edible packaging in particular when impregnated with both CMO/GNS.

Carbon nanostructures in polyvinyl alcohol-based silver nanocomposites for serum albumin concentration sensing

Introducing carbon nanostructures in polyvinyl alcohol (PVA) matrix as strengthening elements by solution dispersion method is already known. Here, the plasmonic sensor surfaces interspersed with carbon nanomaterials are studied for their durable and better sensing capabilities. Carbon quantum dots (CQD) and Multiwall carbon nanotubes (MWCNT) are the carbon nanostructures used in the polyvinyl alcohol-silver nanocomposite to develop plasmonic sensing surfaces. Fiber optic unclad U-bent surfaces are encapsulated in the carbon nanostructure dispersed PVA-silver nanocomposite. The surface is further functionalized with the polyelectrolyte poly(allylamine) hydrochloride (PAH) for better bioconjugation. In the available sensor literature, the evaluation of the sensing layer stability after multiple sensing trials is almost nil. In this work, the sensor surface plasmonic performance after multiple sensing trials is evaluated. The results show that plasmonic biosensors with improved sensing performances can be developed by introducing carbon nanomaterials in PVA-silver nanocomposites. The developed sensor heads are used to sense Bovine Serum Albumin (BSA) concentration changes.

Preparation of cellulose nanofiber/polyvinyl alcohol-based composite films for metal ion detection by starch/disodium calcium ethylenediaminetetraacetate synergistic complexation effect

Heavy metal pollution causes irreversible damage to plants, animals, and humans. Therefore, it is meaningful to develop facile, fast, and efficient strategies for heavy metal ion (HMI) detection. Here, a portable composite film (CPSE) was designed for HMI detection with high sensitivity and wide detection range. The CPSE was prepared by using cellulose nanofibers (CNF)/polyvinyl alcohol (PVA) as the matrix and utilizing modified starch (HPS) to assist disodium calcium ethylenediaminetetraacetate (EDTA-Ca) to form stable complexes with HMI. The R, G and B values (the three primary colors of light) were captured using an image acquisition system to produce an HMI standard color card successfully. Specifically, the composite film can effectively distinguish Cu2+, Pb2+ and Fe3+. The response time of the composite film to HMI was 2–4 s, and the detection ranges of Cu2+ and Fe3+ were 5–700 ppm and 10–1000 ppm, respectively. Additionally, the synergistic effect of HPS and EDTA-Ca led to the increase in tensile strength (1.59–1.71 times), tear strength (3.29–3.57 times), and glass transition temperature (~ 6 °C) compared to CNF/PVA/HPS and CNF/PVA/EDTA-Ca films. This study confirms the value of CPSE films as materials for HMI detection and suggests innovative ideas for designing similar biomass detection materials in the future.

Facile synthesis and antibacterial performance of novel biofilms based on bacterial cellulose from jackfruit rags, incorporating polyvinyl alcohol, Ag nanoparticles, and Eclipta prostrata extract

The advancements of antibacterial biofilms have received much attention in biomedical, wound healing, and food packaging. Here, we developed a novel bacterial cellulose (BC) through Acetobacter xylinum strains using jackfruit rags as a carbon source, under different fermentation conditions. The highest BC production of 5.668 g L–1 of dried weight BC was obtained from the medium with 1: 2 (w v–1) of jackfruit rags/water ratio, 4.5 initial pH and 9 days of incubation. Further bacterial cellulose was incorporated into mixture of polyvinyl alcohol (PVA), biogenic silver nanoparticles (AgNPs) and Eclipta prostrata extract (EPE) to develop antimicrobial films. The micromorphology, mechanical, and functionality of BC/PVA/AgNPs/EPE biofilms were compared with those of BC/PVA, BC/PVA/EPE, BC/PVA/AgNPs film precursors. The results showed that mechanical strength of BC/PVA/AgNPs/EPE biofilms increased, while their water vapor permeability significantly decreased. Fourier transform infrared and scanning electron microscopy revealed excellent compatibility between AgNPs, EPE and the BC/PVA matrix. The BC/PVA/AgNPs/EPE biofilm had strong antibacterial performance against Escherichia coli and Staphylococcus aureus, as the average zone of inhibitions were 18.5 ± 0.33 mm and 21.0 ± 0.3 mm, respectively. These outcomes suggest that the BC/PVA/AgNPs/EPE biofilm can be a good candidate for antibacterial food packaging.

Impact resistance of polyvinyl alcohol-polypropylene fiber toughened foamed concrete under low-velocity impact: experiments and 3D meso-scale modelling

Foamed concrete exhibits good energy absorption and shock absorption properties due to its microporous structure. Compared with conventional concrete, foamed concrete can more readily enter the plastic stage and more effectively reflect and absorb impact energy. However, a scientific deficit of knowledge about the impact resistance of foamed concrete with various hardeners and there is a lack of accurate verified models of such a process. In this study, the impact resistance of polyvinyl alcohol-polypropylene fiber toughened foamed concrete under different impact speeds and different amounts of polyvinyl alcohol has been investigated using the cube drop weight impact test. The toughening mechanism of polyvinyl alcohol is revealed through XRD analysis. In addition, 3D meso-scale modelling of a composite material composed of foam, mortar, an interface transition zone and fiber was conducted using the Python-based secondary development of Abaqus to simulate impact resistance. The results have demonstrated that the impact resistance (ultimate bearing capacity, total absorbed energy and dynamic increase factor) of the toughened foamed concrete samples initially increased and subsequently decreased with the addition of polypropylene fiber and polyvinyl alcohol. At the impact speed of 1.6m/s, compared with ordinary foamed concrete, the ultimate bearing capacity of polyvinyl alcohol polypropylene fiber toughened foamed concrete is increased by 107.8%, the total absorbed energy is increased by 119.7%, and the dynamic increase coefficient is increased by 31.6%; At the impact speed of 2.0m/s, compared with ordinary foamed concrete, the ultimate bearing capacity of polyvinyl alcohol polypropylene fiber toughened foamed concrete is increased by 134.2%, the total absorbed energy is increased by 87.9%, and the dynamic increase coefficient is increased by 50%. The simulation results are in good agreement with the test results, establishing that 3D meso-scale modelling modeling can accurately describe the impact resistance test of foamed concrete. It is further confirmed that 3D meso-scale modelling is reliable for predicting the impact resistance of polymer-fiber toughened foamed concrete.

Influence of copper ion cross-linked CMC-PVA film on cell viability and cell proliferation study

In this study, films composed of carboxymethyl cellulose and polyvinyl alcohol were fabricated using the solution casting method. Citric acid (4 %) was employed as a cross-linking agent, while glycerol (3 %) as a plasticizer. Cupric chloride (CuCl2·2H2O) was used for cross-linking at concentrations 0.5 %, 1 %, and 3 % over different times. The cross-linking with copper ions led to a noticeable reduction in elasticity, with the breaking strain ranging from 17.9 %–52.9 %. The ion hydration phenomenon increased the contact angle and swelling ratio. Fourier-transform infrared (FTIR) spectroscopy confirmed esterification reactions and copper ion cross-linking with sodium carboxymethyl cellulose (Na-CMC). The films showed antibacterial activity against Staphylococcus aureus and Escherichia coli. The ion-released mechanism followed was the non-Fickian super case-II type. The concentration and duration of cross-linking significantly influenced cell viability and proliferation. FE-SEM analysis revealed that effective concentrations of CuCl2.2H2O were 0.5 % and 1 %, and cross-linking times were 5–15 min, facilitating cell attachment and proliferation. Films are non-adhesive with water vapor permeation 800–900 g/m2/day. These results indicate the potential use of the films in treating second-degree burn wounds with low to medium exudate levels. This study provides valuable insights into the development of copper-infused materials for advanced wound healing applications.

Development of Polyvinyl Alcohol/Polyethylene Glycol Copolymer-based Orodispersible Films Loaded with Entecavir: Formulation and In vitro Characterization.

The aim of the study is to prepare entecavir (ETV)-loaded orodispersible films (ODFs) using polyvinyl alcohol (PVA)/polyethylene glycol (PEG) graft copolymer (Kollicoat® IR) as a film-forming agent, and further to evaluate the dissolution rate, mechanical and physicochemical properties of films. ETV-ODFs were prepared by a solvent casting method. The amount of film-forming agent, plasticizer, and disintegrating agent was optimized in terms of the appearance, thickness, disintegration time and mechanical properties of ODFs. The compatibility between the drug and each excipient was conducted under high temperature (60 °C), high humidity (RH 92.5%), and strong light (4500 Lx) for 10 days. The dissolution study of optimal ODFs compared with the original commercial tablet (Baraclude®) was performed using a paddle method in pH 1.0, pH 4.5, pH 6.8, and pH 7.4 media at 37 °C. The morphology of ODFs was observed via scanning electron microscopy (SEM). The mechanical properties such as tensile strength (TS), elastic modulus (EM), and percentage elongation (E%) of ODFs were evaluated using the universal testing machine. The physicochemical properties of ODFs were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR). The related substances were less than 0.5% under high temperature, high humidity, and strong light for 10 days when ETV was mixed with excipients. The optimal formulation of ODFs was set as the quality ratio of Kollicoat® IR, glycerol, sodium alginate (ALG-Na): TiO2: MCC+CMC-Na: ETV was 60:9:12:1:1:1. The drug-loaded ODFs were white and translucent with excellent stripping property. The thickness, disintegration time, EM, TS, and E% were 103.33±7.02 μm, 25.31±1.95 s, 25.34±8.69 Mpa, 2.14±0.26 Mpa, and 65.45±19.41 %, respectively. The cumulative drug release from ODFs was more than 90% in four different media at 10 min. The SEM showed that the drug was highly dispersible in ODFs, and the XRD, DSC, and FT-IR results showed that there occurred some interactions between the drug and excipients. In conclusion, the developed ETV-loaded ODFs showed relatively short disintegration time, rapid drug dissolution, and excellent mechanical properties. This might be an alternative to conventional ETV Tablets for the treatment of chronic hepatitis B.

Significant effects of Rural Wastewater Treatment Plants in Reducing Microplastic Pollution: A Perspective from China's Southwest Area

Sewage systems are a major source for microplastics in riverine exports to oceans. Urban areas are generally considered hotspots for microplastic discharge, whereas emissions from rural areas remain largely understudied. Hence, this study investigated the abundance, characteristics, and polymer types of microplastics in rural wastewater treatment plants (WWTPs) in Guiyang and estimated the annual microplastic emissions of China based on sewage discharge. The influent abundance of microplastics was 3.8-8.2 items/L, the effluent abundance was 3.1-5.9 items/L, with a lower removal rate of 14.4%-54.6%, which might be influenced by lower operating loads and influent concentrations. Raman spectroscopy analysis revealed that polyvinyl alcohol (PVA) was the predominant polymer type. Rural WWTPs were more effective at removing large-sized particles (> 0.1mm) and films, resulting in higher removal effectiveness by weight (49.1%) compared to urban WWTPs (30.8%). Based on the abundance of microplastics in WWTPs within the study area and China's annual sewage discharge, this study estimated the microplastic emissions released through sewage in China in 2022. The annual microplastic emissions through sewage in China were estimated to be 2995.7 tons, with rural and urban areas contributing 25.1% and 74.9%, respectively. Approximately 724.8 tons and 1001.6 tons of microplastics were removed from rural and urban WWTPs, respectively. This work indicates the unignorable emissions of microplastics from rural sewage and highlights the crucial role of rural WWTPs in reducing microplastic pollution.

Yttria-stabilized zirconia and lanthanum cerate granules with YSZ whiskers prepared by spray drying for thermal barrier coatings

The aim of this study was to explore the effect of different solid phases and varied amounts of polyvinyl alcohol (PVA) on granule size of plasma-sprayable yttria-stabilized zirconia (YSZ) with YSZ whiskers (YSZ/W) and lanthanum cerate (La2Ce2O7, LC) with YSZ whiskers (LC/W) as composite powders. The initial phase of this study involved the preparation and optimization of a YSZ suspension using varying solid loadings of YSZ powder (ranging from 30-75 wt.%) and PVA serving as both a binder and dispersant. The suspension was subjected to rigorous optimization procedures to meet the required standards. The suspensions were spray dried, and the resulting granulates were examined using SEM to determine their shape and size. The particle size of YSZ granules increased with increasing solid loading of YSZ in the suspension. The optimum amount of dispersant was found to be 1 wt.% related to the weight of solid, while the solid loading was 75 wt.% of YSZ. In some cases, excessive YSZ solid loading and dispersant impaired the formation of spherical granules. Composite YSZ/W and LC/W granules were also prepared with spherical, lemon, or irregular shapes, with the whiskers embedded in the YSZ or LC powder.

High-strength polyvinyl alcohol/gelatin/LiCl dual-network conductive hydrogel for multifunctional sensors and supercapacitors

The synthesis of conductive hydrogels with high mechanical strength, toughness, optimal fracture growth rate and the capability to detect diverse human body movements poses a significant challenge in the realm of flexible electronics. In this study, a one-pot technique utilized effectively to fabricate conductive materials by doping LiCl into a mixture of polyvinyl alcohol (PVA) and gelatin. The PVA/gelatin/LiCl0.3(PGL) conductive hydrogel demonstrates exceptional robustness, flexibility, and resistance to deformation, enabling the monitoring of various physiological signals such as temperature and humidity. Additionally, the PGL demonstrates exceptional elongation properties (up to 1111.32 %), high lifting capacity (up to 25 kg), resistance to deformation, and sustained stability of peak signals even after 300 cycles at 50 % strain. The hydrogel electrolyte exhibits a conductivity of 2.114 S/m at 25 °C and a specific capacitance of up to 48.75 F/g, along with favorable mechanical and electrochemical characteristics. These findings suggest that the PVA/gelatin/LiCl0.3 hydrogel supercapacitor (PGLSC) conductive hydrogel shows significant potential for integration into flexible electronics and wearable technology devices.

Antimicrobial peptide-based pH-responsive Polyvinyl alcohol hydrogel artificial vascular grafts with excellent antimicrobial and hematologic compatibility

Thrombosis and infection are the primary challenges limiting the clinical application of small-diameter artificial blood vessels. Numerous studies have focused on improving the hemocompatibility of artificial vascular materials, addressing properties such as anticoagulant activity, antithrombogenicity, low hemolysis rates, and reduced platelet adhesion. However, there has been comparatively less attention given to the antibacterial properties of these materials. This study utilizes polyester braided tubes and PVA/PAAm hydrogel materials, combined with surface modification techniques, to develop a pH-responsive antibacterial hydrogel artificial blood vessel graft. The hydrogel surface was grafted with a polymer brush hierarchical structure, and antimicrobial peptide MLT was immobilized to confer antibacterial properties. Additionally, 2,3-dimethylmaleic anhydride (DMMA) was covalently attached as a shielding group to achieve an environment-responsive strategy. The research demonstrates that this artificial blood vessel graft exhibits structural stability, excellent mechanical properties, and good cellular and hemocompatibility. Furthermore, it exhibits pH-responsive capabilities, triggering efficient antibacterial activity in low pH environments. The modified antibacterial hydrogel artificial blood vessel material shows low hemolysis rates, excellent anticoagulant properties, and reduced platelet adhesion. Therefore, the strategy of combining MLT with DMMA may effectively enhance the hemocompatibility and responsive antibacterial performance of artificial blood vessel materials.

A simulated sunlight-activated plastic mimic enzyme for dual-mode detection of D-penicillamine and serum iron

No reports disclosed that whether the plastic centrifuge tube with intrinsic photoenzyme activity can be used for the specific sensing of pharmaceuticals and biomarkers in biofluids so far. We herein report the plastic eppendorf (EP) tube as both reaction vessel and sunlight-activated plastic mimic enzyme for colorimetric/smartphone dual-mode detection of D-penicillamine (D-PA) and iron (Ⅲ) ions in goat and rabbit serums accordingly. The photooxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) combined with simulated sunlight-activated EP tube was selectively inhibited by adding D-PA, and the absorbance at 652 nm of oxidized TMB decreased. Good linearity between the absorbance variation (or R/(R + G + B)) and D-PA level ranging from 10 to 300 µM was obtained, and the limits of detection (LOD) were determined as 8.50 μM (colorimetric) and 6.92μM (smartphone). Furthermore, the polyvinyl alcohol hydrogel encapsulated TMB in EP tube as a smartphone biosensor had been triumphantly used to monitor D-PA level in goat serum. Interestingly, the adsorption band of photo-oxidized EP tube-TMB system inhibited by D-PA gradually increased as the enhancement of iron (Ⅲ) ions concentration. Based on the “on–off-on” effect, a sensitive and selective method was further used for selectively sensing iron (Ⅲ) in rabbit serum. Notably, the dual-mode sensing platforms exhibited outstanding detection performance, with LOD values as low as 0.50 µM and 0.65 µM respectively. In short, this work not only excavated a photoactivated-plastic mimics, but also developed a robust, low-cost, simple and sensitive biosensor for simultaneous detection of D-PA and Fe (Ⅲ) ions in biofluids. The current photoactivated sensor does not requires the introduction of exogenous catalyst except for simulated sunlight, plastic tube and chromogenic substrate.

A novel smart window based on co-crosslinked hydrogel with temperature self-adaptability and anti-freezing functions for building energy saving

Thermochromic smart windows based on hydrogels with adaptive regulation of solar radiation have attracted an increasing attention due to their potential in temperature management. However, hydrogels with extremely high water content may freeze, leading to the risk of transparency reduction and even window breakage in cold environment. In this study, co-crosslinked P(NIPAM-co-AM)@GLY@PVA hydrogel with excellent solar radiation regulation and anti-freezing performance was prepared by introducing antifreeze glycerol (GLY) and polymer polyvinyl alcohol (PVA). By adjusting the amount of GLY, PVA and hydrophilic AM, P(NIPAM-co-AM)@GLY@PVA hydrogel showed a satisfactory thermochromic performance, with a luminous transmittance (Tlum) of 68.05 %, a solar modulation ability (ΔTsol) of 62.11 %, a lower critical solution temperature (LCST) of ∼24 °C and an antifreeze temperature of −15 °C. The thermal management experiments proved that the thermochromic@anti-freezing (TCA) smart window assembled based on P(NIPAM-co-AM)@GLY@PVA hydrogel had an excellent performance in managing indoor temperature and cyclic stability. This work may open a new avenue to solve problems in the application field of hydrogel-based smart windows

Mechanism of antimony oxidation and adsorption using immobilized Klebsiella aerogenes HC10 in soil

Klebsiella aerogenes HC10 is one of the few strains isolated from contaminated soil that efficiently oxidizes Sb. However, the sensitivity of microorganisms to environmental conditions limits Sb-oxidizing bacteria applications in soil remediation. Immobilizing Sb-oxidizing bacteria is a promising strategy to improve colonization rates and microorganism inefficiencies and to strengthen bioremediation in Sb-contaminated soil. This study evaluated the feasibility of an immobilization approach to enhance Sb oxidation and the remediation performance of strain HC10 in soil. The results indicated that a mixed matrix of polyvinyl alcohol and sodium alginate as fixed carriers provided a porous microstructural environment conducive to HC10 colonization and proliferation. Sb(III) concentration was reduced by 9.8 mg/L. The total Sb decreased by 3.8 mg/L by immobilized HC10 after 7 d. Key metabolites involved in Sb oxidation and adsorption were significantly upregulated. In soil, immobilized HC10 removed 48.68 % and 61.74 % of water-extractable and citric acid-extractable Sb(III), respectively. Some well-crystallized (hydr)oxide Sb fractions binding to the mineral surface were transformed into the mineral lattice form, creating an inner-sphere complex that effectively immobilized Sb. Immobilized HC10 enhanced hydrogen peroxidase, urease, and sucrase activities related to soil antioxidants and nutrient cycling. Immobilized HC10 promoted the proliferation of indigenous bacteria, which emerged as the dominant bacterial community with the potential for Sb oxidation. The ars operon genes associated with Sb resistance and transport were significantly expressed in HC10 treatments, providing a crucial basis for colonization in the soil. These results highlight the potential of immobilized Sb-oxidizing bacteria for enhanced bioremediation of Sb-contaminated soil.