Long Polymer Chains Research Articles

Post-Treating Grain Boundaries and Surface Defects by Long-Chain Polymer for Highly Efficient and Stable Perovskite Solar Cells.

Grain boundaries (GBs) and surface defects within perovskite films are inherent challenges that affect the photovoltaic performance of perovskite solar cells (PSCs. In this work, Nylon 11 (N11) is utilized, a long-chain polymer, for post-treating the GBs and surface defects within FAPbI3 films. The multifunctional groups of N11 exhibit unique passivation abilities, enabling self-regulation and selective correction of reverse-charged defects. Post-treating with N11 results in high-quality FAPbI3 films characterized by tight GBs and low surface defect density. Despite fabrication under full open-air conditions, the N11 post-treatment significantly enhances the power conversion efficiency (PCE) value of FAPbI3 PSCs, increasing it from the reference value of 21.89% to 23.54%. Importantly, the long alkyl chain present in N11 significantly enhances the humidity stability of the PSCs. Unencapsulated PSCs treated with N11 maintain 89% of their initial PCE after exposure to air with 30% relative humidity (RH) for 1000h, demonstrating resilience to elevated humidity levels. This work highlights the substantial improvement in the photovoltaic performance of PSCs achieved through the post-treatment with N11.

Zophobas morio versus Tenebrio molitor: Diversity in gut microbiota of larvae fed with polymers

Plastics are common synthetic materials that have been abundantly present as pollutants in natural ecosystems for the past few decades. Thus scientists have investigated the capability of plastic digestion by insects. Here we compare the effectiveness of biodegradation of the specific polymers: expanded polystyrene (EPS), polyvinyl chloride (PVC), low-density polyethylene (LDPE) and polypropylene (PP) altogether with above variants of plastics with microelements and vitamins by the mealworm – the larval form of the beetle Tenebrio molitor – and larvae of the beetle Zophobas morio, known as superworms. Z. morio beetles on all diets were able to complete their life cycle from larvae through pupae and imago, gaining 19 % and 22 % in mass on LDPE and EPS; 8 % and 7 % on PVC and PP. Mealworms (T. molitor) reared on polymers had minimal weight gain, gaining 2 % on LDPE and EPS, and a slight reduction in mass was observed when reared on PP and PVC. Not all specimens of T. molitor were able to pupate and transform to the adult stage. The results suggest that larvae of Z. morio can eat and degrade some types of plastic compounds more effectively than T. molitor. The changes in microbial gut communities were compared between these two species. The highest mass gain for Z. morio is associated with higher diversity in gut microbia and it was more diverse than that of T. molitor. Citrobacter freundii, a bacterium recognized for its ability to degrade long-chain polymers, linear hydrocarbons and cyclic hydrocarbons, was found in the microflora of Z. morio. The results confirm that superworms can survive on polymer feed. Moreover, this diet supplemented with microelements and vitamins increases the number of bacterial species and the diversity in the microbial gut.

Numerical investigation on the enhanced heat transfer characteristics of non-Newtonian viscoelastic fluids in microchannel with chip arrays

Elastic turbulence is an efficient heat transfer method at microscale. In this work, we conduct a systematic investigation on the flow and heat transfer performances of viscoelastic polymer solutions in microchannels with chip arrays by means of high-fidelity numerical simulations. Focusing on the effects of fluid elasticity [i.e. polymer relaxation time (λ)] and flow Reynolds number (Re), we find that the synergistic interplay between inertial and elastic forces is strategically exploited to amplify convection, thereby facilitating an enhanced heat transfer performance. For highly elastic fluid, the Nusselt number (Nu) can be improved by 76.13 % compared to that of less elastic fluid, while the pressure drop is reduced appropriately. In addition, as the fluid elasticity increases, the pressure drop decreases and eventually converges to a constant. In the zone of elastic turbulence, the fluid reinforces the convective heat transfer, which can be ascribe to the deformation of long-chain polymer molecules. Particularly, we consider the effect of temperature-dependent λ on the heat transfer performance. Our results demonstrate that the increased temperature-dependent λ decreases the value of Nu, and the variation between values of variable and constant λ is reduced with increasing Re or λ. Hence, in some cases of large fluid elasticity or high Re, it is possible to safely ignore the impact of temperature-dependent λ with an acceptable accuracy. The present work provides important insights into the enhanced heat transfer via elastic turbulence, which could guide the applications in the field of chip cooling.

Transition transferases prime bacterial capsule polymerization.

Capsules are long-chain carbohydrate polymers that envelop the surfaces of many bacteria, protecting them from host immune responses. Capsule biosynthesis enzymes are potential drug targets and valuable biotechnological tools for generating vaccine antigens. Despite their importance, it remains unknown how structurally variable capsule polymers of Gram-negative pathogens are linked to the conserved glycolipid anchoring these virulence factors to the bacterial membrane. Using Actinobacillus pleuropneumoniae as an example, we demonstrate that CpsA and CpsC generate a poly(glycerol-3-phosphate) linker to connect the glycolipid with capsules containing poly(galactosylglycerol-phosphate) backbones. We reconstruct the entire capsule biosynthesis pathway in A. pleuropneumoniae serotypes 3 and 7, solve the X-ray crystal structure of the capsule polymerase CpsD, identify its tetratricopeptide repeat domain as essential for elongating poly(glycerol-3-phosphate) and show that CpsA and CpsC stimulate CpsD to produce longer polymers. We identify the CpsA and CpsC product as a wall teichoic acid homolog, demonstrating similarity between the biosynthesis of Gram-positive wall teichoic acid and Gram-negative capsules.

In-situ surface modified water-soluble Cu nanoparticles as lubrication additives in water-based cutting fluids

Water-based lubricants are essential in the field of tribology, and the application of nanoparticles as additives in water-based lubricants shows promise and significant practical importance. In this study, water-soluble Cu nanoparticles modified with methoxypolyethyleneglycol xanthate long-chain polymers were fabricated by a in-situ surface modification method. The tribological behavior of the Cu nanoparticles synthesized as additives in a water-PEG system was evaluated using a universal micro-tribotester. It was found that the synthesized nanoparticles could be stably dispersed in the water-PEG system and could enhance the tribological properties and load-carrying capacity of the system significantly. For example, the coefficient of friction could be reduced to 0.052, and the PB value increased to 588 N when the Cu nanoparticles were added at a mass fraction of 1.5 %. This was mainly attributed to the formation of a boundary lubrication film consisting of Cu, Fe2O3, Fe2(SO4)3, and FeS throughout the entire friction process. The boundary film effectively prevents direct contact between the friction surfaces, thereby improving the tribological properties. The incorporation of Cu nanoparticles as additives into commercial cutting fluids resulted in a lower coefficient of friction and significantly enhanced the extreme pressure performance of the cutting fluids, demonstrating promising application prospects.

In-situ defect passivation assisted three-step printing of efficient and stable formamidine-lead bromide solar cells

Perovskite solar cells (PSCs) emerge as the most promising photovoltaics (PV) for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies. The printed PSCs with simplified device architecture and fabrication procedures could further enhance the competitive strength of PSC technology. In this work, we present an in-situ defect passivation (ISDP) assisted full-printing of high performance formamidine-lead bromide (FAPbBr3) PSCs. Only three rapid printing steps are involved for electron transporting layer (ETL), perovskite and carbon to form a complete solar cell on the low-cost fluorine-doped tin oxide (FTO) substrate. Long-chain polymer monomethyl ether polyethylene glycol is particularly utilized as the ISDP passivator, leading to conformal coating on the rough FTO and defect passivation for both ETL and perovskite during printing. A high efficiency of 10.85% (certified 10.14%) and a high Voc up to 1.57 V are achieved for the printed device. The unencapsulated PSCs maintain above 90% of the initial efficiency after continuously heating at 85 °C for 1000 h and over 80% of the efficiency after the maximum power point tracking for 3500 h. The fully printed semitransparent PSCs with carbon grids (CGs) show average visible light transmittance over 33% and an efficiency of 8.81%.

Elastic particle model for coil-stretch transition of dilute polymers in an elongational flow

The phenomenon of the ‘coil-stretch’ (C-S) transition, wherein a long-chain polymer initially in a coiled state undergoes a sudden configuration change to become fully stretched under steady elongational flows, has been widely recognized. This transition can display intricate hysteresis behaviours under specific critical conditions, giving rise to unique rheological characteristics in dilute polymer solutions. Historically, microscopic stochastic models and Brownian dynamics simulations have shed light on the underlying mechanisms of the transition by uncovering bistable configurations of polymer chains. Following the initial work by Cerf (J. Chem. Phys., vol. 20, 1952, pp. 395–402), we introduce a continuum model in this study to investigate the C-S transition in a constant uniaxial elongational flow. Our approach involves approximating the unfolding process of the polymer chain as an axisymmetric deformation of an elastic particle. We make the assumption that the particle possesses uniform material properties, which can be represented by a nonlinear, strain-hardening constitutive equation to replicate the finite extensibility of the polymer chain. Subsequently, we analytically solve for the steady-state deformation using a polarization method. By employing this reduced model, we effectively capture the C-S transition and establish its specific correlations with material and geometric properties. The hysteresis phenomena can be comprehended through a force-balance analysis, which involves comparing the externally applied viscous forces with the intrinsic elastic responsive forces. We demonstrate that our model, while simple, unveils rich elastohydrodynamics of the C-S transition.

Signaling of Plant Defense Mediated by Receptor-like Kinases, Receptor-like Cytoplasmic Protein Kinases and MAPKs Triggered by Fungal Chitin in Horticultural Crops

Fresh horticultural products are economically significant foods that are highly demanded by consumers worldwide; however, they are highly perishable and susceptible to deterioration by fungi, which contribute to their short shelf-life and cause significant post-harvest losses. Among the alternatives suggested for fungal control in plants is the elicitation of the innate plant defense mechanism, which may be activated when specific molecules of the phytopathogen, such as chitin, are recognized. Chitin is a long-chain polymer of N-acetyl-α-D-glucosamine of the fungal cell wall; it possesses biological activity by eliciting the plant immune response. This molecule and its oligosaccharides are recognized through transmembrane receptors known as receptor-like kinases (RLKs) and receptor-like proteins (RLPs). Mediated by receptor-like cytoplasmic kinases (RLCKs), which bind to the intracellular domain of these receptors, they initiate intracellular signal transduction via MAP kinases, triggering the plant defense response. In model plants, such as Oryza sativa (rice) and Arabidopsis thaliana, the set of RLK/RLP-RLCK-MAP kinases is involved in plant immunity triggered by chitin. Furthermore, in horticultural products, research into the molecular events between these three elements has suggested that similar processes occur. However, little is known about these molecular events in fruits. Against this background, the present review provides the most recent and relevant findings on the molecular associations of these three elements in the response to fungal chitin in plants and outlines which elements could participate in this signaling process in horticultural crops.

Abstract 1398: The role of ST8SIA2 & ST8SIA4 in melanoma progression and metastasis

Abstract Melanoma is the deadliest form of skin cancer; while early detection affords patients a 5-year survival rate greater than 90 percent, survival for metastatic patients is poor. Metastatic dissemination is reliant on melanoma’s ability to escape immune surveillance and migrate to distant organs. These processes are heavily influenced by cell surface proteins, which themselves can be regulated by post-translational modifications (PTM) like protein glycosylation. An understudied glycosylation that may affect immune evasion and cancer progression is polysialylation (polySia). Here, a long-chained polymer of sialic acid moieties is formed by the polysialyltransferases ST8SIA2 and ST8SIA4. In silico analysis suggests that compared to normal skin, primary cutaneous melanoma has elevated expression of both ST8SIA2 and ST8SIA4. Interestingly, although ST8SIA4 is upregulated in metastatic samples, its expression is associated with increased survival. Further analysis revealed a positive correlation between CD8+ T cell infiltrates and ST8SIA4 expression. Furthermore, analysis of ST8SIA2 expression shows an inverse correlation with survival and T Cell CD8+ cells infiltration, suggesting ST8SIA2 and -4 differentially regulate the tumor immune microenvironment. One potential polySia modified cell surface protein, mediating these effects is Cell Adhesion Molecule 1 (CADM1). CADM1 is a target of ST8SIA2 and may also be modified by ST8SIA4. Loss of CADM1 increases the invasive properties of melanoma cells and our recent point mutational analysis reveals that the adhesive function of CADM1 might be regulated by polySia at Asp 113. In addition to its role in cancer migration and invasiveness, CADM1 expression may also affect the tumor immune environment. Further investigations are needed to untangle the complex relationship between PolySia modification and melanoma immune evasion and metastasis. Citation Format: Amirali Amirfallah, Kayla Gallant, Maria Cavallo, Zongguan Huang, Edward Hartsough. The role of ST8SIA2 & ST8SIA4 in melanoma progression and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1398.

Hierarchical aerogels based on cellulose nanofibers and long-chain polymers for enhancing oil–water separation efficiency

The hydrophobic chain length of biomass-based aerogels used for oil–water separation was evaluated as a major parameter influencing the aerogels’ hydrophobicity. The properties of the porous structure were enhanced by the hierarchical assembly of the aerogels with biopolymeric structural units and polymer mineralization. The cellulose network was strengthened through silanization, and the nanocellulose network was further enhanced through coating with mineralizers containing long-chain hydrophobic molecules. Interfacial engineering was employed to establish multiscale interactions through the freeze-drying-induced modification of cellulose nanofibers and mineralized coatings of long-chain alkyl polymers. The resulting hierarchically structured aerogel exhibits low density (11.4 kg/m3), excellent mechanical compression properties across a wide temperature range (capable of enduring 100 cycles of compression), high porosity (99.2%), superhydrophobicity (152°), and recyclability. It maintains a 57.9% adsorption rate even after 40 adsorption–desorption tests, while also preserving its shape integrity. Moreover, it can be recycled and reused. At a temperature of 700 °C, the mass loss was only 44.47%, with excellent thermal stability. The aerogel can reduce oil pollutants in the ocean by adsorption, recover oil resources, and protect the natural environment. The assembly and optimization of nanofibrous matrix interfaces through the mineralization of long-chain polymers enhanced the performance of functionalized cellulose-based aerogels.

Closed-Loop Recyclable and Nonpersistent Polyethylene-like Polyesters.

ConspectusAliphatic polyesters based on long-chain monomers were synthesized for the first time almost a century ago. In fact, Carothers' seminal observations that founded the entire field of synthetic polymer fibers were made on such a polyester sample. However, as materials, they have evolved only over the past decade. This is driven by the corresponding monomers becoming practically available from advanced catalytic conversions of plant oils, and future prospects comprise a possible generation from third-generation feedstocks, such as microalgae or waste. Long-chain polyesters such as polyester-18.18 can be considered to be polyethylene chains with a low density of potential breakpoints in the chain. These do not compromise the crystalline structure or the material properties, which resemble linear high-density polyethylene (HDPE), and the materials can also be melt processed by injection molding, film or fiber extrusion, and filament deposition in additive manufacturing. At the same time, they enable closed-loop chemical recycling via solvolysis, which is also possible in mixed waste streams containing polyolefins and even poly(ethylene terephthalate). Recovered monomers possess a quality that enables the generation of recycled polyesters with properties on par with those of the virgin material. The (bio)degradability varies enormously with the constituent monomers. Polyesters based on short-chain diols and long-chain dicarboxylates fully mineralize under industrial composting conditions, despite their HDPE-like crystallinity and hydrophobicity. Fundamental studies of the morphology and thermal behavior of these polymers revealed the location of the in-chain groups and their peculiar role in structure formation during crystallization as well as during melting. All of the concepts outlined were extended to, and elaborated on further, by analogous long-chain aliphatic polymers with other in-chain groups such as carbonates and acetals. The title materials are a potential solution for much needed circular closed-loop recyclable plastics that also as a backstop if lost to the environment will not be persistent for many decades.

Tuning phase separation in DPPDTT/PMMA blend to achieve molecular self-assembly in the conducting polymer for organic field effect transistors.

The semiconductor/insulator blends for organic field-effect transistors are a potential solution to improve the charge transport in the active layer by inducing phase separation in the blends. However, the technique is less investigated for long-chain conducting polymers such as Poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT), and lateral phase separation is generally reported due to the instability during solvent evaporation, which results in degraded device performance. Herein, we report how to tailor the dominant mechanism of phase separation in such blends and the molecular assembly of the polymer. For DPPDTT/PMMA blends, we found that for higher DPPDTT concentrations (more than 75%) where the vertical phase separation mechanism is dominant, PMMA assisted in the self-assembly of DPPDTT to form nanowires and micro-transport channels on top of PMMA. The formation of nanowires yielded 13 times higher mobility as compared to pristine devices. For blend ratios with DPPDTT ≤ 50%, both the competing mechanisms, vertical and lateral phase separation, are taking place. It resulted in somewhat lower charge carrier mobilities. Hence, our results show that by systematic tuning of the blend ratio, PMMA can act as an excellent binding material in long-chain polymers such as DPPDTT and produce vertically stratified and aligned structures to ensure high mobility devices.

Tailoring molecular weight distribution via polymer degradability

An alternative approach for controlling the polymer molecular weight distribution (MWD) was developed based on the degradation of precisely synthesized degradable long-chain polymers.

Ambient-air crystallization of CsPbIBr2 films with polymer towards stable and efficient carbon-based perovskite solar cells

Cesium lead mixed-halide all-inorganic perovskite solar cells (PSCs) exhibit promising balance between the efficiency and environmental stability in contrast to hybrid PSCs. Nonetheless, they face challenges due to rapid crystallization of solution processed perovskite film, resulting in elevated lattice defect density and energy loss. Therefore, a hydrophobic long-chained polymer, polypropylene carbonate (PPC) is added in varying concentrations to CsPbIBr2 precursor solution to yield a good-quality film under ambient air and low-temperature conditions. Here, the 2 % PPC added film displayed improved crystallinity and morphology and large grain-size with passivated grain-boundaries. The absorption intensity of the film was largely enhanced with reduced charge recombination and tuned energy level alignment at perovskite/carbon interface which enhanced both efficiency and stability of hole-transport layer free C–IPSCs in ambient air (humidity∼ 65–70 %). The efficiency increased upto 7.36 % which is 62.4 % higher than the bare device, attributed to its increased photovoltage (1.17 V–1.25 V), current-density (8.42 mA cm−2 to 10.25 mA cm−2), and fill-factor (46 %–57.5 %). Furthermore, optimized device has a significantly longer lifetime than bare device. Hence, this work presents a simple strategy for developing commercially feasible PSCs.

Psychrobacter species enrichment as potential microplastic degrader and the putative biodegradation mechanism in Shenzhen Bay sediment, China

Microplastic (MP) pollution has emerged as a pressing environmental concern due to its ubiquity and longevity. Biodegradation of MPs has garnered significant attention in combatting global MP contamination. This study focused on MPs within sediments near the sewage outlet of Shenzhen Bay. The objective was to elucidate the microbial communities in sediments with varying MPs, particularly those with high MP loads, and to identify microorganisms associated with MP degradation. The results revealed varying MP abundance, ranging from 211 to 4140 items kg–1 dry weight (d. w.), with the highest concentration observed near the outfall. Metagenomic analysis confirmed the enrichment of Psychrobacter species in sediments with high MP content. Psychrobacter accounted for ∼16.71% of the total bacterial community and 41.71% of hydrocarbon degrading bacteria at the S3 site, exhibiting a higher abundance than at other sampling sites. Psychrobacter contributed significantly to bacterial function at S3, as evidenced by the Kyoto Encyclopedia of Genes and Genomes pathway and enzyme analysis. Notably, 28 enzymes involved in MP biodegradation were identified, predominantly comprising oxidoreductases, hydrolases, transferases, ligases, lyases, and isomerases. We propose a putative mechanism for MP biodegradation, involving the breakdown of long-chain plastic polymers and subsequent oxidation of short-chain oligomers, ultimately leading to thorough mineralization.

Development of an Antiswelling Hydrogel System Incorporating M2-Exosomes and Photothermal Effect for Diabetic Wound Healing.

Diabetic wounds represent a persistent global health challenge with a substantial impact on patients' health and overall well-being. Herein, a hydrogel system that integrates functionalized gold nanorods (AuNRs) and M2 macrophage-derived exosomes (M2-Exos) was developed to achieve an efficient and synergistic therapy for diabetic wounds. We introduced an ion-cross-linked dissipative network into a prefabricated covalent cross-linked network (long-chain polymer network), which was prepared using AuNRs as a specific cross-linker. The ion network was then cross-linked with the long-chain polymer in situ to form a specific network structure, imparting antiswelling and photothermal effects to the hydrogel. This integrated hydrogel system effectively scavenged reactive oxygen species levels, inhibited inflammation, promoted angiogenesis, and stimulated photothermal antibacterial activity through near-infrared (NIR) irradiation. To demonstrate the potential of the hydrogel, we established experimental animal models of oral mucosa ulceration and full-thickness skin defects. In vivo results confirmed that M2-Exos released from the hydrogels played a crucial role in wound closure. Furthermore, the synergistic effect of AuNRs and NIR photothermal effects eradicated bacterial infections in the wound area. Overall, our integrated hydrogel system is a promising tool for accelerating chronic diabetic wound healing and tissue regeneration. This study highlights the potential benefits of combining bioactive M2-Exos and the photothermal effect of AuNRs into an antiswelling hydrogel platform to achieve satisfactory wound healing in patients with diabetes.

A Living Topochemical Ring-Opening Polymerization of Achiral Amino Acid N-Carboxy-Anhydrides in Single Crystals.

A living topochemical ring-opening polymerization (ROP) of achiral amino-acid N-carboxyanhydrides (NCAs) is reported. Single crystals of the NCAs of α-aminoisobutyric acid (Aib) and 1-aminocyclohexanecarboxylic acid (ACHC) were grown, allowing a ring-opening polymerization macroscopically induced by amines. The single crystals could be polymerized at temperatures from 25-50 °C after physically contacting the amine-based initiator with the crystals. Topochemical polymerization of the crystals was proven by MALDI-ToF MS and XRD, generating polymers with chain lengths of up to 40 units and a complete affixation of the initiating amine at the polymer's head. Due to the proper alignment of the reacting groups in the crystal, longer polymer chains with improved purities can be reached, as chain-transfer is reduced as compared to solution polymerization. Simple purification of the polymers can be achieved by separation of the unreacted NCA via dispersion in acetonitrile. Overall, this method enables the preparation of polymers with higher chain length and purities at mild conditions, finally demonstrating a crystal-based ring opening polymerization.

Toward industrial scale-up of polypeptide synthesis: analysis of monomer suitability

Polypeptide is a class of biopolymers that mimic the structure and properties of natural proteins, which makes it fitting for biological applications. The biodegradability and biocompatibility from the peptide backbones combined with the tunability from synthetic chemistry allow for long-chain polypeptides to function for drug delivery, tissue grafting, and gene therapy. Currently, long-chain polypeptides (≥100 amino acids) are not synthesized on a commercial scale (>100 kg.) Based on the potential applications, the optimization of polypeptide production should be discussed at the current stage. Since the majority of the polypeptide synthesis depends on the production of monomer and the polymerization of the monomer into polypeptides, choosing the most suitable monomer for industrial application is critical in designing a polypeptide production line. Based on an industrial standpoint, the ideal monomer should be synthesized conveniently, stored and transported easily, and polymerized efficiently. This article aims to compare and examine the four major groups of monomers used in a laboratory setting: protect amino acid, N-carboxyanhydride (NCA), N-thiocarboxyanhydride (NTA), and N-phenoxycarbonyl-functionalized α-amino acid (NPCA) based on the industrialization criteria stated above, using past experimental results. In the end, NPCA proves to be the most suitable monomer for industrial purposes. Like NCA, NPCA can be synthesized efficiently and can be polymerized into a diverse collection of polypeptides both based on conjugation and structure. Like NTA, NPCA can be synthesized and stored in an open-air environment. Still, NPCA has disadvantages in polymerization efficiency, requiring multiple days for long-chain polymers. Potentially, by increasing the leaving group conjugated to the amino acid, improvement can be made to the polymerization efficiency.

Deacetylation of chitin oligomers by Fusarium graminearum polysaccharide deacetylase suppresses plant immunity.

Chitin is a long-chain polymer of β-1,4-linked N-acetylglucosamine that forms rigid microfibrils to maintain the hyphal form and protect it from host attacks. Chitin oligomers are first recognized by the plant receptors in the apoplast region, priming the plant's immune system. Here, seven polysaccharide deacetylases (PDAs) were identified and their activities on chitin substrates were investigated via systematic characterization of the PDA family from Fusarium graminearum. Among these PDAs, FgPDA5 was identified as an important virulence factor and was specifically expressed during pathogenesis. ΔFgpda5 compromised the pathogen's ability to infect wheat. The polysaccharide deacetylase structure of FgPDA5 is essential for the pathogenicity of F. graminearum. FgPDA5 formed a homodimer and accumulated in the plant apoplast. In addition, FgPDA5 showed a high affinity toward chitin substrates. FgPDA5-mediated deacetylation of chitin oligomers prevented activation of plant defence responses. Overall, our results identify FgPDA5 as a polysaccharide deacetylase that can prevent chitin-triggered host immunity in plant apoplast through deacetylation of chitin oligomers.

Hydrogel-based intelligent greenhouse films for simultaneous fogging prevention and indoor environmental monitoring

Fogging prevention and environmental monitoring in a greenhouse are usually accomplished by different components, as the former relies on persistent surface-wetting capability, while the latter requires conductivity or capacitance to vary with ambient conditions. Combining these seemingly unrelated functions presents a significant challenge. Here, we report an all-in-one hydrogel that integrates these exclusive functions, enabling it to simultaneously work as an anti-fogging coating and environmental monitor in greenhouses. The strategy involves constructing loosely crosslinked hydrophilic networks enriched with abundant free ions and a specific amount of glycerol. The transparent hydrogel, composed of long-chain polymers, exhibits excellent adhesion to the inner surface of the greenhouse film and significantly decreases its water contact angle by filmwise condensation, thereby reinforcing the anti-fogging properties of the film without sacrificing its transparency. Meanwhile, the presence of glycerol and free ions enables the gel to sustain a wide range of temperature and humidity while displaying environmentally sensitive conductivity, endowing the gel with the same function as conventional rigid environmental sensors. As a proof-of-concept demonstration, a wireless indoor environmental monitoring system in a homemade lean-to greenhouse is established by utilizing hydrogel as the sensing module, which also performs well in prohibiting fogging on the greenhouse film. We hope this work could provide some inspiration for the development of multifunctional intelligent greenhouse films.