ACS Applied Polymer Materials最新文献

The hydrogel drug delivery system has demonstrated significant potential in addressing the limitations of chemotherapeutic medicines and tumor-targeted treatment. Nintedanib, an FDA-approved potent triple vascular kinase inhibitor, has exhibited effective antitumor activity in a variety of malignancies, although its underlying mechanism remains elusive. In this investigation, an innovative sustained-release hydrogel delivery system for medication was established using the Michael addition reaction of the polyethylene glycol diacrylate and 4-arm poly(ethylene glycol)-thiol (4 Arm PEG-SH). It was discovered that the nintedanib@PEG hydrogel induced cell apoptosis and inhibited tumor progression. Subsequently, analysis revealed that nintedanib caused apoptosis in colon cancer cells by upregulating PUMA (p53 upregulated modulator of apoptosis) expression while also activating protective autophagy. Mechanistically, nintedanib inhibited Akt/mTOR (mechanistic target of rapamycin kinase) pathway activation, thereby inducing PUMA-dependent apoptosis and triggering protective autophagy. Moreover, the combination of nintedanib and CQ (chloroquine, an autophagy inhibitor) contained in the hydrogel delivery system showed a synergistically antitumor effect both in vitro and in vivo. Consequently, an in situ-targeted, long-term, effective, and safe antitumor strategy using an innovative injectable hydrogel delivery system combined with complementary medication. These findings propose a promising therapeutic approach for clinical patients, particularly in the realm of colon cancer therapy, thereby illuminating potential avenues for further research and clinical application.

In order to protect the ecosystem from the impact of plastic film pollution, it is necessary to explore biodegradable materials for producing a plastic film. In this study, mulch film was prepared using biochar as the fertilizer carrier, Enteromorpha polysaccharide (EP), and konjac glucomannan (KGM) as the film’s matrix. The result of Fourier transform infrared (FTIR) showed that the Enteromorpha polysaccharide extracted from Enteromorpha prolifera (E. prolifera) was rich in hydroxyl, carboxyl, and sulfonic groups. The result of FTIR, scanning electron microscopy (SEM), and energy-dispersive spectroscopy of biochar proved that urea was successfully loaded in biochar, and the urea loading capacity of biochar reached 17.8%. The transmittance of EP/KGM/urea-loaded biochar film (urea-BCF) was less than 3%, which meets the requirements of the black mulch film. The degradation rate of the mulch in the soil can reach 68.3% after 80 days of burial, indicating an excellent degradation performance. The SEM results showed that the biochar particles were distributed uniformly in the membrane matrix. In addition, the leaching experiments showed that the release of urea achieved an equilibrium after 20 h, with a cumulative of almost 76.9%. This method not only achieves the high value utilization of E. prolifera but also provides a simple strategy for preparing mulch film.

Functional silanes are multifaceted cross-linkers, compatibilizers, coupling agents, and surface modifiers. Herein, we present organofunctional polysiloxane building blocks that offer great versatility in terms of molecular weight, degree of condensation, and the choice and loading of organic substituent groups. The organofunctional polyethoxysilanes (funPEOS) are prepared in a one-pot, two-step process: synthesis of the PEOS carrier/substrate, followed by grafting a functional silane “shell”, both based on condensation with acetic anhydride. The reaction was optimized at the lab scale and scaled up to a 7 L reactor. The acetylation, condensation, and hyperbranched structure of the carrier were confirmed by ²⁹Si NMR, while ²⁹Si–²⁹Si 2D INADEQUATE NMR provides strong evidence for the grafting of functional silanes onto the carrier (Q–T coupling). IR, ¹H, and ¹³C NMR spectroscopy demonstrate that the functional groups remain intact. The molar mass can be tailored by stoichiometric control of the acetic anhydride to silane monomer ratio (M_n 3500–20,000 g/mol). The compounds are stable organic liquids with a long shelf life. Selected applications are presented: scratch-resistant coatings with water contact angles of ∼90°, stable water emulsions, and surfactant-free, mesoporous silica foams.

Despite the potential of polylactic acid (PLA) as a biodegradable polymer, widespread applications have been limited by its inherent flammability and brittleness. To overcome these issues, PLA was combined with a composite-reinforced flame-retardant filler (A-MBC/PA/A-TiO₂) consisting of γ-aminopropyl triethoxysilane (APTES)-grafted microcrystalline bagasse cellulose (A-MBC), phytic acid (PA), and APTES-silylated titanium dioxide nanoparticles (A-TiO₂). When 10 wt % A-MBC/PA/A-TiO₂ was incorporated, the tensile and impact strengths of the PLA composite increased by 15 and 22%, respectively, relative to those of pristine PLA. The addition of 10 wt % A-MBC/PA/A-TiO₂ resulted in PLA composites with a UL-94 V-0 rating and a high limiting oxygen index of 29% owing to a synergistic flame-retardant mechanism in the gas and condensed phases. The presence of A-MBC/PA/A-TiO₂ contributed to the formation of a solid carbon layer containing P and Ti in the condensed phase as well as the release of PO· free radicals and N-containing noncombustible gases in the gas phase, which reduced the flammable gas and oxygen concentrations, thus providing a synergistic flame-retardant effect. In addition, molecular dynamics simulations of the PLA/(A-MBC/PA/A-TiO₂) composite system were performed. The numerical and analytical results showed that A-MBC and A-TiO₂ in the filler interacted strongly with the PLA matrix, which was beneficial for distributing the flame retardant in PLA and improving its mechanical and flame-retardant properties. This work demonstrates a strategy for simultaneously improving the flame retardancy and mechanical properties of PLA composites using a biobased composite flame retardant.

Lipid accumulation is a prominent pathologic feature of nonalcoholic fatty liver disease (NAFLD), which is due to imbalances in triglycerides metabolism. However, none of the available therapeutic strategies have been able to achieve the effective removal of triglycerides from the lesion site. Herein, MIP@QUE, a mimetic transporter with a high affinity for triglycerides, was synthesized using molecular imprinting. The physicochemical features of MIP@QUE are such that it binds to triglycerides and releases the drug in an affinity-driven reaction. In vivo and in vitro experiments showed that the metabolism of triglycerides was promoted by dual activation of the autophagy-lysosomal pathway through the size effect of the molecularly imprinted polymer (MIP) and the pharmacological action of quercetin (QUE). Moreover, MIP@QUE not only reduced triglyceride accumulation to reverse hepatic steatosis but also effectively lowered the level of oxidative stress to reduce hepatocellular damage. Targeting the key causative factors of NAFLD, MIP@QUE offers an effective therapeutic strategy to control the disease process by promoting the lysosomal transport and metabolism of triglycerides in hepatocytes; it also serves as a platform for the treatment of triglyceride-related metabolic syndrome.

Self-nucleation behavior is a critical phenomenon in polymer crystallization, and the impact of the chemical structure on this behavior has been extensively investigated. However, the underlying mechanism has not been fully elucidated. In this study, the self-nucleation behavior of a series of polyolefins with varying degrees of fluorine substitutions is comprehensively surveyed. Incorporation of fluorine atoms, which increase the polarity of polyolefin chains, considerably improves the self-nucleation ability, resulting in an apparent expansion of the temperature widths of Domain II for poly(vinyl fluoride) and poly(vinylidene fluoride) in comparison with polyethylene. However, further fluorine substitution diminishes the self-nucleation ability of fluoropolyolefins. Then, the correlation between the self-nucleation ability and dielectric constant is studied. It is found that the width of Domain IIb increases monotonously with respect to dielectric constant, expect for poly(vinylidene fluoride) which exhibits a slightly narrow Domain IIb than poly(vinyl fluoride). However, a rather wide Domain IIa appears in poly(vinylidene fluoride). Based on the intermolecular interactions, a correlation between the width of Domain II and the dielectric constant is reasonably established. Further, Fourier transformation infrared spectroscopy directly reveals that the hydrogen-bonding interactions between C–F and C–H are the essential reason for the self-nucleation behavior of fluoropolyolefins. However, in combination with the intriguing disappearance of self-nucleation behavior for the ethylene–tetrafluoroethylene alternating copolymer, the isomer of poly(vinylidene fluoride), and ethylene–chlorotrifluoroethylene alternating copolymer, it is unveiled that the possible scattering, isolated F···H–C hydrogen bonds in fluoropolyolefin are not a sufficient condition for endowing self-nucleation behavior. Thus, an interacting mechanism of long-range continuous structure of hydrogen bond is speculated for the display of the self-nucleation ability of fluoropolyolefins. This work deepens the understanding of self-nucleation crystallization in fluoropolyolefins and provides guidance for the melt processing.

Conductive polymer composites with a segregated structure have been developed for flexible piezoresistive sensors, but segregated composites usually suffer from the problem of poor interfacial bonding. In this work, ethylene-vinyl acetate copolymer (EVA)/carbon nanotube (CNT)/hydroxylated carbon nanotube (CNT-OH) composites with segregated structures were prepared by ball-milled coating and the following hot-press molding, in which dynamic boron-centered three-dimensional cross-linking networks were constructed in EVA granules. The interfacial bonding was significantly improved by molecular bridges at the interface based on thermo-activated transesterification between CNT-OH and EVA vitrimer granules. As a result, the composites with the ratio of CNT to CNT-OH of 3:1 showed a superior elongation-at-break of 563.69%, strength of 12.6 MPa, and conductivity of 13.6 S/m. Furthermore, a 3D porous structure was constructed in the EVA composites by supercritical carbon dioxide foaming. Benefiting from the segregated conductive structure and strong interfacial bonding, the segregated conductive EVA foams exhibited an excellent piezoresistive sensing sensitivity with a GF of −23.6 and compression stability. It provided an approach for interface strengthening of segregated conductive polymer composites, and the resulting conductive foams exhibited great potential for the application as a flexible piezoresistive sensor.

Pendimethalin (PDM) is a chemically synthesized herbicide and is primarily employed to control broadleaf weeds and woody plants. It enters our environment from production industries and from human activity in farming. Pendimethalin residues in edible foodstuffs and water sources are a serious worldwide problem as they are linked to various health issues. As such, there is an urgent need for the construction of a portable point-of-care (PoC) testing device for the detection of pendimethalin residues from food and vegetables before being consumed. Considering this challenge, an aggregation-induced enhance emission (AIEE) polymer PF2CN is developed by modifying the conjugated backbone of polyfluorene-based polymer PFP. The insertion of an M2CN monomer into the conjugated backbone of PF2CN plays a key role in tuning the photophysical property of the PF2CN polymer where it shows AIEE activity with red-shifted emission. Further, the PF2CN polymer shows remarkable sensitivity and selectivity toward PDM with a limit of detection (LOD) of 2.8 nM, which is much less than the standard maximum residual limits for pesticides in food. Notably, the simultaneous occurrence of PET and FRET serves as a “receptor-free” selective sensor for PDM. Furthermore, the designed PF2CN conjugated polymer-based PDM detection process is miniaturized into a prototype smartphone device, thereby providing a rapid and practical solution for on-site toxic analyte detection, thereby providing higher environmental safety and protection.

Polyelectrolyte complexes (PECs) have wide ranging applications spanning medicine, fire safety, and electronic materials. For years, PECs presented processing challenges owing to their ionic bonds, which limited them to use as coatings. Chemistry was recently developed to additively manufacture PECs of polyethylenimine and poly(methacrylic acid) through vat photopolymerization, but the use of solvent compromised the mechanical properties and vat stability of the parts. Here, two reactive diluents, hydroxyethyl methacrylate and dimethyl acrylamide, are substituted for the solvent used in prior work on printable PEC resins. Parts printed with these reactive diluents have nearly identical processing parameters but exhibit significantly increased storage modulus, especially at elevated temperatures, when compared to that of the control resin. Thermally driven amidization of the carboxylate and ammonium groups yields further control over the properties of the parts. The combination of spatial, thermomechanical, and hydrophilic control promises to dramatically expand the application space of polyelectrolyte materials.

Aloe represents a valuable resource for the Mediterranean economy; the pharmaceutical and nutraceutical industries exploit the Aloe gel for several applications, but about 45 wt % of the Aloe plant, i.e., the leaf peel, is waste. This waste is usually disposed off in a landfill or used as a fertilizer. The possibility to give added value and a second life to the portions of Aloe Vera waste will help this growing market enter a circular economy perspective. In this work, waste collected from the local Sardinian cultivation of Aloe Vera was employed to prepare microcrystalline cellulose (MCC). Cellulose was purified from anthraquinones, lignin, and hemicellulose through hydrolytic procedures using eco-friendly solvents. Anthraquinone biocomponents, as well as lignin and hemicellulose, were quantified and intended for other valorization processes. At the same time, the cellulose fraction was further converted into MCC and characterized by NMR and infrared spectroscopy and X-ray analyses. TGA-IR and SEM microscopy analyses were performed to investigate the structural changes of MCC during the extraction and postfunctionalization processes. MCC derivatives were finally used as cross-linkers in the photopolymerization and light-induced 3D printing (VAT printing) of acrylic monomers and hydrogels.