Ester Research Articles

Iminodiacetic acid enhances the mechanical and degradation properties of copolyesters by hydrogen bonding and branching

The development of biodegradable polyester materials is of great significance in alleviating the problem of plastic pollution. Poly(butylene terephthalate adipate) (PBAT) is a typical aliphatic-aromatic copolyester and has a capacity of several hundred thousand tons per year. However, the relatively low mechanical strength and high requirement for degradation environment of PBAT limit its application fields. To compensate for the deficiencies in mechanical and degradable properties of PBAT, this study reports a molecular chain structure design on the amorphous region using diethyl iminodiacetate (DEI). A series of poly(butylene adipate iminodiacetate terephthalate) (PBAIT) with a DEI content of 5–20 mol% were obtained. DEI contains secondary amine groups, which can be amidated with ester bonds to produce branched sites, and branched structures can be formed from 75 to 79 % of DEI during the copolymerization process. PBAIT-10 exhibit better tensile strength (23.87 MPa), tensile modulus (108.2 MPa) and hydrophilicity than those of PBAT. In addition, PBAIT-10 also shows very high toughness, with an elongation at break of over 1000 %. PBAITs can be degraded in enzymatic or hydrolytic environments. The degradation mechanism was analyzed by 1H NMR spectra and FTIR, and further combined with 2D-IR analysis, which reveals the rapid degradation of the BI chain segments regardless of whether or not they form branched sites. This work provides an idea to prepare copolyesters that combine good mechanical properties with degradability under mild conditions.

Carboxylesterase-activatable multi-in-one nanoplatform for near-infrared fluorescence imaging guided chemo/photodynamic/sonodynamic therapy toward cervical cancer

Traditional tumor treatment faces great challenge owning to inherent drawbacks. Activatable prodrugs with multi-modality therapeutic capacity are highly desired. In this consideration, a responsiveness-released multi-in-one nanoplatform, PLGA-PEG@HC, toward cervical cancer therapy was innovatively developed. Among the nanoplatform, HC was constructed by incorporating chlorambucil, a classic chemotherapy drug into a near-infrared photo- and sono-sensitizer, HCH via ester linker, which can be specifically hydrolyzed by carboxylesterase (CES). HC is scarcely fluorescent and toxic due to the caging of HCH and chlorambucil, thus achieving low background signal and minimal side effects. However, once selectively hydrolyzed by tumor enriched CES, ester bond will be broken. Consequently, HCH and chlorambucil are released so as to achieve near-infrared fluorescence imaging and synergistic photodynamic/sonodynamic/chemo therapy. PLGA-PEG packaging ensures the biocompatibility of HC. The as-obtained nanoplatform, with diameter of 97 nm, achieves tumor targeting capacity via EPR. In vitro and in vivo applications have demonstrated that PLGA-PEG@HC can accumulate in tumor tissues, exhibit CES-activatable near-infrared fluorescence imaging and efficient tumor suppression capacity. Compared with the reported combinational therapy materials which are complex in compositions, PLGA-PEG@HC is simple in formulation but demonstrates near-infrared fluorescence traced and considerable therapy efficacy toward tumors, which may accelerate the clinical translation.

Structure-based clustering and mutagenesis of bacterial tannases reveals the importance and diversity of active site-capping domains.

Tannins are critical plant defense metabolites, enriched in bark and leaves, that protect against microorganisms and insects by binding to and precipitating proteins. Hydrolyzable tannins contain ester bonds which can be cleaved by tannases-serine hydrolases containing so-called "cap" domains covering their active sites. However, comprehensive insights into the biochemical properties and structural diversity of tannases are limited, especially regarding their cap domains. We here present a code pipeline for structure prediction-based hierarchical clustering to categorize the whole family of bacterial tannases, and have used it to discover new types of cap domains and other structural insertions among these enzymes. Subsequently, we used two recently identified tannases from the gut/soil bacterium Clostridium butyricum as model systems to explore the biochemical and structural properties of the cap domains of tannases. We demonstrate using molecular dynamics and mutagenesis that the cap domain covering the active site plays a major role in enzyme substrate preference, inhibition, and activity-despite not directly interacting with smaller substrates. The present work provides deeper knowledge into the mechanism, structural dynamics, and diversity of tannases. The structure-based clustering approach presents a new way of classifying any other enzyme family, and will be of relevance for enzyme types where activity is influenced by variable loop or insert regions appended to a core protein fold.

Plasmalogens in Innate Immune Cells: From Arachidonate Signaling to Ferroptosis.

Polyunsaturated fatty acids such as arachidonic acid are indispensable components of innate immune signaling. Plasmalogens are glycerophospholipids with a vinyl ether bond in the sn-1 position of the glycerol backbone instead of the more common sn-1 ester bond present in "classical" glycerophospholipids. This kind of phospholipid is particularly rich in polyunsaturated fatty acids, especially arachidonic acid. In addition to or independently of the role of plasmalogens as major providers of free arachidonic acid for eicosanoid synthesis, plasmalogens also perform a varied number of functions. Membrane plasmalogen levels may determine parameters of the plasma membrane, such as fluidity and the formation of microdomains that are necessary for efficient signal transduction leading to optimal phagocytosis by macrophages. Also, plasmalogens may be instrumental for the execution of ferroptosis. This is a nonapoptotic form of cell death that is associated with oxidative stress. This review discusses recent data suggesting that, beyond their involvement in the cellular metabolism of arachidonic acid, the cells maintain stable pools of plasmalogens rich in polyunsaturated fatty acids for executing specific responses.

One-pot Hydrogenolysis of Polyethylene Terephthalate (PET) to p-xylene over CuZn/Al2O3 Catalyst.

Chemical upcycling of plastic wastes into valuable chemicals is a promising strategy for resolving plastic pollution, but economically viable methods currently are still lacking. Here, we report one-pot hydrogenolysis of PET plastic into p-xylene with an excellent yield (99.8 %) over a robust non-precious Cu-based catalyst, CuZn/Al2O3, in the absence of alcohol solvents. The presence of Zn species promotes the dispersion of Cu0 and increases the ratio of Cu+/Cu0, whereas the synergistic effect of Cu0 and Cu+ leads to a superior performance in the conversion of PET. The combination of GC-MS, 13C CP MAS NMR, 2D 1H-13C CP HETCOR NMR spectroscopy and kinetic studies for the first time demonstrates 4-methyl benzyl alcohol as an important reaction intermediate in the hydrogenolysis of PET. Mechanistic studies indicate that the conversion of PET mainly follows a hydrogenolysis process, involving the cleavage of ester bonds to alcohols and the C-O bond cleavage of alcohols to alkanes. This work not only brings new insight for understanding the upgrading pathway of PET, but also provides a guidance for the design of high-performance non-precious catalysts for the chemical upcycling of plastic wastes.

Depolymerization and Etching of Poly(lactic acid) via TiCl4 Vapor Phase Infiltration.

This study investigates the use of TiCl4 vapor phase infiltration (VPI) to cleave ester groups in the main chain of a polymer and drive depolymerization and film etching. Prior investigations have demonstrated that the infiltration of TiCl4 into PMMA results in dealkylation of its ester bond, cleaving its side groups. This study investigates the VPI of TiCl4 into poly(lactic acid), which is a prototypical polymer with an ester group in its main chain. Utilizing in situ quartz crystal microbalance (QCM) measurements and spectroscopic ellipsometry, PLA is observed to depolymerize readily at 135 °C with extended TiCl4 precursor exposure, resulting in significant thickness and mass reduction, whereas at 90 °C, depolymerization is significantly slower and etching is negligible. Utilizing Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and a residual gas analyzer (RGA), dealkylation is shown to be the primary depolymerization mechanism. FTIR and XPS analyses reveal the consumption of carbonyl and methoxy groups and the emergence of hydroxyl, chlorine, and titanium moieties. In situ RGA measurements provide further insights into the byproducts formed during the TiCl4 and water exposure steps, indicating that the depolymerized components undergo further breakdown into other substances. Residuals left after 135 °C TiCl4 VPI are easily removed with a 0.1 M HCl aqueous solution. These findings highlight the expanding functionality of VPI, revealing its capability as both an additive and subtractive process and suggesting its broader applications.

Intrusion kinetics and interfacial degradation mechanism of PU-steel system in chloride ion environment: A multiscale study

This study utilised density functional theory (DFT) to predict the movement pathways and rates of chloride ions within polyurethane (PU), as well as their molecular dynamics and charge distribution during the erosion process. Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and electrochemical tests revealed chemical and electrochemical changes at the PU/steel interface after immersion in sodium chloride solution. Shear strength and nanoindentation tests were used to examine the impact of microscale erosion on macroscale mechanical properties. The results showed that chloride-ion penetration into PU requires overcoming a substantial energy barrier driven by the concentration gradient between the saline solution and PU. After immersion in sodium chloride solution, the −NCO functional groups in PU were disrupted, reducing chemical stability and molecular elasticity. This process accelerates the hydrolysis of ester bonds, leading to a decline in interfacial mechanical properties. Electrochemical results showed that the resistance of the PU coating decreased over time, indicating a transition in the electrochemical reactions that eventually led to interfacial corrosion. After prolonged immersion, both the interfacial shear strength and modulus significantly decreased, whereas the shear ductility initially increased but later decreased.

Activated Phenyl Ester Vitrimers.

Aromatic esters are amongst the oldest known chemical motifs that allow for thermal (re)processing of thermosetting polymers. Moreover, phenyl esters are generally known as activated esters that do not require a catalyst to undergo acyl transfer reactions. Even though dynamic aromatic esters find applications in commercialized thermoset formulations, all-aromatic esters have found limited use so far in the design of covalent adaptable networks (CAN) as a result of their high glass transition temperature (Tg)and specific curing process. Here, a strategy to include partly aromatic esters as dynamic cross-links inside low Tg (-40°C) thermosetting formulations, using aliphatic esters derived from para-hydroxybenzoic acid, which serves as a highly activated phenol or as a reactive "phenylogous anhydride" is reported. A small molecule study shows that the activated phenyl ester bonds can readily exchange with free phenol moieties at 200°C under catalyst-free conditions, while the addition of a catalyst allows for a faster exchange. Robust and hydrophobic polymer networks are conveniently prepared via rapid thiol-ene UV-curing of unsaturated phenol esters. The obtained networks show high thermal stability (350°C), fast processability, good water resistance, and low creep up to 120°C, thus showing good promise as a platform for CAN.

Rapid preparation of bioadhesive hydrogels containing catechol moieties at room temperature with reproducible adhesion to wet tissues, antimicrobial, antioxidant capacity for noncompressive hemostasis

In order to cope with the massive tissue bleeding caused by sudden trauma and the demand for bioengineering materials with adjustable wet adhesion properties, this study formed the first layer of network by adding galactomannan (GG) and collagen (Col) structure, and then use the Fe3+-urushiol (UH) redox system to activate free radicals to initiate the polymerization of acrylic acid (AA) to quickly form an interpenetrating double network hydrogel. The cis hydroxyl group in GG and the hydroxyl group of UH form dynamic covalent borate ester bonds with borate ions in the borax solution, and use their responsiveness to pH to control the catechol group to achieve controllable adhesion. UH and Fe3+ endowed the hydrogel with excellent antibacterial ability, while adding Col enhanced the mechanical properties of the hydrogel. The elastic modulus and toughness increased from 4.32 kPa and 92.9 kJ/m3 to 18.90 kPa and 264.54 kJ/m3. In addition, due to the joint action of UH and Col, the hydrogel dressing can achieve rapid hemostasis within 20 s. In short, this hydrogel dressing has good biocompatibility, inherent antibacterial ability, adjustable moist tissue adhesion properties and rapid hemostatic ability, and is expected to become a candidate for wound hemostasis dressing.

Injectable Hydrogels for Programmable Nanoparticle Release

AbstractInjectable hydrogels represent a promising strategy for the extended release of biological molecules, thereby reducing the frequency of injections. This study introduces a novel system based on Michael addition of dextran and polyethylene glycol (PEG) polymers functionalized with oxanorbornadiene (OND) and thiol groups, respectively. Reliable control over gelation speed allows administration by injection using a simple syringe‐to‐syringe mixing protocol that entrains more than 95% of virus‐like particle (VLP) cargo. A combination of retro‐Diels‐Alder and hydrolytic ester bond cleavage gives rise to programmable release of the VLPs. Different release profiles, including burst, linear, and delayed release over a two‐week period, are engineered using different OND linkages, and rheological characterization shows the hydrogels to be well within the desired range of stiffness for subcutaneous use. The modular nature of this system offers a generalizable platform for developing degradable materials aimed at sustained release biomedical applications.

Biodegradation of commercial polyester polyurethane by a soil-borne bacterium Bacillus velezensis MB01B: Efficiency, degradation pathway, and in-situ remediation in landfill soil

Polyurethane (PU), a widely used and durable plastic, persists in the environment, resulting in significant waste management challenges. Therefore, developing eco-friendly degradation technologies, such as screening for efficient biodegrading microorganism strains, is urgently needed to address this issue. Bacillus velezensis MB01B, an efficient polyester PU-degrading bacterium, was isolated from landfill soil and demonstrated the ability to degrade 91.4% of 0.75% Impranil DLN within 24 h under the optimal conditions (30.5 °C and initial pH 6.5). To assess the degradation capability of MB01B, three PU substrates of increasing complexity—Impranil DLN film, polyester thermoplastic polyurethane (TPU) film, and commercial PU desk mat—were tested; after 30 days, weight losses of 24.8%, 18.3%, and 5.4% were observed, respectively. In addition, SEM images showed significant morphological changes on the surface of these PU materials after treatment with MB01B. FTIR analysis of Impranil DLN films following degradation showed reductions in key functional groups (ester and urethane); and the identification of neopentyl glycol and 1,6-hexanediol as degradation intermediates suggested MB01B possesses the capability to hydrolyze ester and urethane bonds. Concurrently, genome sequencing combined with RT-qPCR identified several enzymes, including urethanases and esterases/lipases, involved in PU degradation. Based on these results, the pathway for MB01B to degrade Impranil DLN was inferred. Finally, MB01B was successfully formulated into a solid microbial inoculum with favorable storage properties and used for in-situ degradation of the commercial PU materials (Impranil DLN films, TPU films and PU desk mats) in landfill soil, underscoring its potential for the in-situ biological treatment of PU plastic wastes.

Enhanced bioremediation of bensulfuron-methyl contaminated soil by Hansschlegelia zhihuaiae S113: Metabolic pathways and bacterial community structure

Bensulfuron-methyl (BSM), a widely used herbicide, can persist in soil and damag sensitive crops. Microbial degradation, supplemented with exogenous additives, provides an effective strategy to enhance BSM breakdown. Hansschlegelia zhihuaiae S113 has been shown to efficiently degrade this sulfonylurea herbicide. However, depending solely on a single strain for degradation proves inefficient and unlikely to achieve ideal remediation in practical applications. This study assessed the impact of various carbon sources on the degradation efficiency of S113 in BSM-polluted soil. Among these, glucose was the most effective, achieving a 98.7 % degradation rate after 9 d of inoculation. In addition, seven intermediates were detected during BSM degradation in soil through the cleavage of the phenyl ring ester bond, the pyrimidine rings, and urea bridge peptide bond, among other pathways. 2-amino-4,6-dimethoxy pyrimidine (ADMP), and 2-(aminosulfonylmethyl)-methyl benzoate(MSMB) were the primary intermediates. These metabolites were less toxic to maize, sorghum, and bacteria than the BSM. Community structure analysis indicated that variations in exogenous carbon sources and environmental pollutants significantly improved the ecological functions of soil microbial communities, enhancing pollutant degradation. Addition of carbon sources notably affected soil microbial community structure, modifying metabolic activities and interaction patterns. Specifically, glucose substantially increased the richness and diversity of soil bacterial communities. These findings offer valuable insights for field remediation practices and contributed to the development of more robust soil pollution management strategies.

ENHANCE THE AQUEOUS SOLUBILITY OF DICLOFENAC THROUGH THE SYNTHESIS OF DICLOFENAC-INOSITOL PRODRUG

Due to limited aqueous solubility, poor bioavailability makes oral dosage formulations difficult to formulate. Chemical alteration of medicinal compounds improves solubility. Prodrug design is a popular molecular modification method that improves solubility and oral bioavailability. This study aims to synthesize a diclofenac prodrug to enhance aqueous solubility. In this study, diclofenac was esterified with inositol to make a prodrug (DIP), which was identified by 1H-NMR and FT-IR. A computational pharmacokinetic software was used to study DIP's pharmacokinetic profile, and saturation solubility was measured in phosphate buffer (pH 6.8) and 0.1 HCl (pH 1.2) solutions. The ester bands of (C=O) stretch at 1739 cm-1 and the elimination of H signals of carboxylic acid at 10-12 ppm in the 1H-NMR spectrum proved the synthesis of (DIP). Diclofenac solubility increased 827-fold in phosphate buffer solution (p < 0.05) from 0.059± 0.0164 mg/ml to 48.8± 0.034 mg/ml, primarily due to polarity change. The solubility of diclofenac and (DIP) in 0.1 N HCl (pH 1.2) was 0.016± 0.0031 and 0.018± 0.002, respectively. The improvement in solubility in the acidic medium was non-significant (p > 0.05) due to acid hydrolysis of the ester bond between inositol and the drug. The synthesis of diclofenac prodrug can greatly enhance its water solubility.

Chemical Recycling of Epoxy Thermosets: From Sources to Wastes

As one of the most widely used thermosets due to its excellent performances, epoxy resin (EP) is widely used in various fields and often employed as a component of composite actuator devices, strengthening their mechanical properties. However, the expanding production of EP inevitably leads to the accumulation of waste end-of-life equipment and the corresponding increasingly serious environmental problems. This review summarizes the recycling strategies of EP, divided into two perspectives: recycling from wastes and sources. Chemical recycling is expected to be the future of waste EP treatment, and we discuss the chemical recycling methods of existing waste EP based on different mechanisms, including the selective cleavage of ester bonds, C–N bonds, and C–O bonds. On the other hand, epoxy vitrimer networks based on various dynamic covalent linkages are also outlined, which can respond to multiple external stimuli and provide materials with recyclability from the origin. Therefore, the use of epoxy vitrimer actuators can prevent waste generation throughout the whole lifecycle. We present some issues of concern in both waste-based and source-based recycling strategies and emphasize the significance of scaling-up. Finally, we summarized the current situation and present some future perspectives with the aim of making practical contributions to environmental issues.

Mechanically robust, self-healing and stretchable electromagnetic shielding materials based on multi-component dynamic bonded polyurethane elastomer

Stretchable self-healing electromagnetic interference (EMI) shielding materials can automatically restore their original performance after mechanical damage, and can still maintain over 20 dB EMI shielding effectiveness (EMI SE) under tensile state. In this work, a series of highly stretchable self-healing polyurethane elastomer PUBNS-X was prepared by introducing dynamic disulfide bonds, boronic ester bonds and boron-nitrogen coordination (B-N) on the polyurethane main chain. It was found that B-N coordination significantly increased the elongation at break and the tensile strength. The high dynamic reversibility of boronic ester, disulfide bond and B-N coordination bond synergistically endowed PUBNS-X with excellent temperature-triggered self-healing properties. The mechanical properties of PUBNS-X can be restored to more than 90 % at 60 °C. The pre-assembled silver nanowires (AgNWs) conductive network was then introduced into the polyurethane surface by taking advantage of the fluidity of the dynamically bonded polyurethane backbone to obtain a series of stretchable self-healing electromagnetic shielding composites (AgNWs/PUBNS-Y). The results showed that the EMI SE of AgNWs/PUBNS-Y can reach ∼55 dB, and the conductivity can be restored to 82 % of the original value after healing at 60 °C. The investigation of the electromagnetic interference shielding performance of composites under different strains showed that the EMI SE of AgNWs/PUBNS-3 can still maintain 20 dB under 90 % strain. These composites will have broad potential applications in the fields of flexible wearable electronic products, bionic intelligent materials and soft robots.

Carrier-free nanomedicine for combined antibacterial therapy through pH-responsive controlled release of sulfadiazine and emodin

To mitigate bacterial drug resistance and enhance antibacterial efficacy in the treatment of bacterial infections, a novel antibacterial self-releasing nanomedicine was developed in this study. The innovative nanodrug integrates the active components of traditional Chinese medicine with antibiotics to circumvent bacterial resistance. Additionally, phenylboronic acid (PBA) was used as a bacterial targeting agent to specifically localize the infection site and regulate drug release. In this system, sulfadiazine (Su), emodin (Em), and PBA were assembled through boron ester bonds and hydrophobic interactions, forming a stable self-delivery nanodrug designated as Su/Em/PBA. Subsequently, the drug release capability was evaluated at pH 5.5 and pH 7.4. Notably, the boronic acid ester bond formed by PBA is pH-responsive, demonstrating a significantly higher release of Su and Em in the acidic microenvironment of bacterial infections (pH 5.5) compared to physiological environment (pH 7.4) (Su: 93.9 % vs. 29.9 %; Em: 81.9 % vs. 16.4 %). This indicated that Su/Em/PBA exhibited an effective drug release capability at the site of bacterial infection. The bactericidal effect was evaluated through in vitro plate staining experiments and live/dead bacterial staining assays. The combination of Su and Em enhanced the antibacterial efficacy of Su/Em/PBA, achieving antibacterial rates of 84.0 % against Staphylococcus aureus (S. aureus) and 88.6 % against Escherichia coli (E. coli), signifying the effective antibacterial properties of Su/Em/PBA. In conclusion, our study presents a straightforward approach to developing antibacterial self-releasing nanomedicine with excellent antibacterial activity, making it a promising candidate for future clinical trials.

Construction and application of fluorescent probe and sensing aerogel with ability to detect hydrogen sulfide

The dyeing, wastewater acidification and anaerobic treatment processes in the textile always produce a large amount of hydrogen sulfide (H2S), which will be harmful to the human beings. The fluorescent detection of H2S with highly specific and sensitive probe is of significance. Here, using the 2, 7-dichlorofluorescein (DCF) derivative DCF-MPYM as the fluorophore, a fluorescent probe M1 for specifically recognizing H2S was designed and synthesized by introducing 2-chloro-5-nitrobenzoic acid into the oxanthracene moiety of DCF-MPYM. The introduction of 2-chloro-5-nitrobenzoic acid results in DCF-MPYM being in a closed-loop state, thus, the fluorescence quantum yield (Φ) of the probe M1 was low. The characteristic of weak fluorescence plays an important role in the use of a fluorescent probe. The fluorescence titration and selectivity results demonstrated that the probe M1 could selectively detect H2S, and its detection limit for H2S was calculated to be 45.31 μM. The reaction mechanism of the probe was verified by the high-resolution mass spectrometry (HRMS) and liquid chromatography as the nucleophilic addition of H2S to the probe M1, which induced the cleavage of ester bond and subsequently restored the spectral properties of DCF-MPYM. To bring the probe M1 into practical application, the fluorescent aerogel CMC-M1 was constructed by mixing the probe M1 and carboxymethyl cellulose sodium (CMC-Na) aerogel, and the fluorescent aerogel can be applied in absorbing and removing H2S in water. The adsorption capacity and removal efficiency of CMC-M1 for H2S were 0.626 mg·g−1 and 99.36 %. The investigation of adsorption kinetic showed that the adsorption effect of CMC-M1 towards Na2S was mainly chemical adsorption. In addition, the fluorescent aerogel CMC-M1 can be applied for qualitative, quantitative detection and effective removal of H2S in dyeing and finishing wastewater.

Ethanolamine and Vinyl-Ether Moieties in Brain Phospholipids Modulate Behavior in Rats.

Plasmalogens are brain-enriched phospholipids with a vinyl-ether bond at the sn-1 position between the glycerol backbone and the alkyl chain. Previous studies have suggested that plasmalogens modulate locomotor activity, anxiety-like behavior, and cognitive functions in rodents; however, the specific moieties contributing to behavioral regulation are unknown. In this study, we examined the behavioral modulation induced by specific phospholipid moieties. To confirm the permeability of phospholipids in injected liposomes, we measured the fluorescence intensity following intravenous injection of liposomes containing ATTO 740-labeled dioleoylphosphatidylethanolamine. Then, we compared the behavioral effects following injection of liposomes composed of egg phosphatidylcholine (PC) and 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine (PE 18:0/22:6), PC 18:0/22:6, 1-(1Z-octadecenyl)-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine (PE P-18:0/22:6), or PC P-18:0/22:6, into the tail vein of male rats. The time spent in the central region of the open field was significantly reduced after injection of PE 18:0/22:6, harboring an ester bond at sn-1 compared to controls. Furthermore, the discrimination ratio in the novel object recognition test was significantly higher in PC 18:0/22:6 compared to PE 18:0/22:6, suggesting that the substitution of ethanolamine with choline can enhance recognition memory. We demonstrate that the structures of the sn-1 bond and the hydrophilic moiety in the phospholipids can modulate exploratory behaviors and recognition memory in rodents.

Development of polyvinyl alcohol/carboxymethylcellulose-based bio-packaging film with citric acid crosslinking and clove essential oil encapsulated chitosan nanoparticle pickering emulsion

This study developed polyvinyl alcohol (PVA)/carboxymethylcellulose (CMC)-based films, using citric acid (CA) as a non-toxic crosslinking agent, to enhance the shelf life of water-soluble packaging films. Clove essential oil (CEO)-loaded chitosan nanoparticles (CSNPs) were prepared via Pickering emulsion and incorporated into PVA/CMC/CA composite films. The encapsulation of CEO was confirmed by FTIR and optical microscopy. Thermal properties were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), revealing improved thermal stability and a decrease in glass transition temperature (Tg) upon crosslinking. The formation of ester bonds was confirmed by ATR-FTIR and 13CNMR. Water contact angle (WCA) measurements showed a decrease in hydrophilicity, enhancing the barrier properties of the films. SEM images demonstrated good dispersion of CSNP/CEO within the matrix, improving mechanical and barrier properties. The films exhibited a 30 % reduction in water vapor permeability and water solubility. Controlled release studies indicated that the composite films sustained CEO release, extending the shelf life of cherry tomatoes. Thus, these PVA/CMC/CA-CSNP/CEO composite films offer strong potential for food preservation applications.

A novel label-free impedance biosensor for KRAS G12C mutations detection based on PET-RAFT and ROP synergistic signal amplification

The KRAS G12C mutations, as crucial biomarkers, are closely associated with non-small cell lung cancer. Here, a novel label-free electrochemical biosensor with synergistic signal amplification of photocell energy transfer-reversible addition fragmentation chain transfer (PET-RAFT) and ring-opening polymerization (ROP) was developed for the first time for sensitive detection of KRAS G12C mutations. Specifically, hairpin DNA (hDNA), which act as biomolecular probe, was self-assembled on Au electrode surface by Au-S bond. 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl] pentanoic acid (CDTPA), the chain transfer agent of PET-RAFT reaction, was then attached to hDNA via amide bond. After that, the target DNA (tDNA) was captured on the electrode surface by complementary base pairing with hDNA. Subsequently, large numbers of electro-active monomers N-acryloxysuccinimide (NAS) were successfully grafted to the electrode surface via PET-RAFT reaction, which provided plenty of junction sites for doxorubicin-polycaprolactone (Dox-PCL) synthesized by ROP. Finally, the Dox-PCL was connected to the electrode surface by ester bond, significantly amplifying the electrochemical signal. Under optimized conditions, the biosensor has a wide linear detection range of 0.1 pM to 1 μM, with a detection limit of 86.9 fM. Attribute to its high sensitivity, specificity, reproducibility and stability, this biosensor possesses considerable potential in early diagnosis of disease and biomedical research.