-
Food Chemistry Jun 2024The accurate determination of polar cationic pesticides in food poses a challenge due to their high polarity and trace levels in complex matrices. This study...
The accurate determination of polar cationic pesticides in food poses a challenge due to their high polarity and trace levels in complex matrices. This study hypothesized that the use of halloysite nanotubes (HNTs) can significantly enhance the extraction efficiency and sensitivity of these analytes because of their rich hydroxyl groups and cation exchange sites. Therefore, we chemically incorporated HNTs with organic polymer monoliths for in-tube solid-phase microextraction (SPME). This novel hybrid monolith extended service life, improved adsorption capacity, and exhibited excellent extraction performance for polar cationic pesticides. Based on these advancements, a robust and sensitive in-tube SPME-HILIC-MS/MS method was constructed to determine trace levels of polar cationic pesticides in complex food matrices. The method achieved limits of detection of 1.9, 2.1, and 0.1 μg/kg for maleic hydrazide, amitrole, and cyromazine, respectively. The spiked recoveries in five food samples ranged from 80.2 to 100.8%, with relative standard deviations below 10.7%.
PubMed: 38943962
DOI: 10.1016/j.foodchem.2024.140205 -
Environment International Jun 2024The presence in seawater of low-molecular-weight polyethylene (PE) and polydimethylsiloxane (PDMS), synthetic polymers with high chemical resistance, has been...
The presence in seawater of low-molecular-weight polyethylene (PE) and polydimethylsiloxane (PDMS), synthetic polymers with high chemical resistance, has been demonstrated in this study for the first time by developing a novel methodology for their recovery and quantification from surface seawater. These synthetic polymer debris (SPD) with very low molecular weights and sizes in the nano- and micro-metre range have escaped conventional analytical methods. SPD have been easily recovered from water samples (2 L) through filtration with a nitrocellulose membrane filter with a pore size of 0.45 μm. Dissolving the filter in acetone allowed the isolation of the particulates by centrifugation followed by drying. The isolated SPD were analysed by H nuclear magnetic resonance spectroscopy (H NMR), identifying PE and PDMS. These polymers are thus persisting on seawater because of their low density and the ponderal concentrations were quantified in mg/m. This method was used in an actual case study in which 120 surface seawater samples were collected during two sampling campaigns in the Mediterranean Sea (from the Gulf of Salerno to the Gulf of Policastro in South Italy). The developed analytical protocol allowed achieving unprecedented simplicity, rapidity and sensitivity. The H and C NMR structural analysis of the PE debris indicates the presence of oxidised polymer chains with very low molecular weights. Additionally, the origin of those low molecular weight polymers was investigated by analysing influents and effluents from a wastewater treatment plant (WWTP) in Salerno as a hot spot for the release of SPD: the analysis indicates the presence of low molecular weight polymers compatible with wax-PE, widely used for coating applications, food industry, cosmetics and detergents. Moreover, the origin of PDMS debris found in surface seawater can be ascribed to silicone-based antifoamers and emulsifiers.
PubMed: 38943925
DOI: 10.1016/j.envint.2024.108839 -
Solid State Nuclear Magnetic Resonance Jun 2024A numerical simulation method, namely, SDNMR-WEBFIT, is reported for simulating proton spin diffusion NMR based on the Levenberg-Marquardt algorithm and a pseudo-2D...
A numerical simulation method, namely, SDNMR-WEBFIT, is reported for simulating proton spin diffusion NMR based on the Levenberg-Marquardt algorithm and a pseudo-2D diffusion model. This method is used for the precise quantification of dynamics heterogeneity of the interphase within multiphase polymer systems. The numerical simulation method provides measurements of spin-lattice relaxation time (T), proton density (ρ), lamellar thickness (d), and spin diffusion coefficient (D) for each component. The pseudo-2D diffusion model is employed to simulate the proton spin diffusion build-up/decay curves, simultaneously calculating the lateral fraction of island-like structures (x-ratio). Such approach was successfully applied to various polymer systems, such as semi-crystalline polymer (Poly(ε-caprolactone), PCL), block copolymers (Styrene-butadiene-styrene triblock copolymer, SBS), and plasticized semi-polymers (Polvinyl alcohol, PVA).
PubMed: 38943921
DOI: 10.1016/j.ssnmr.2024.101946 -
Spectrochimica Acta. Part A, Molecular... Jun 2024Newly designed and synthesized derivatives of pentaphenylbenzene with methoxy-substituted carbazolyl or diphenylamino moieties were investigated to estimate their...
Newly designed and synthesized derivatives of pentaphenylbenzene with methoxy-substituted carbazolyl or diphenylamino moieties were investigated to estimate their applicability as hole transport materials. Both the compounds exhibit high thermal stability. The intramolecular charge transfer is blocked for the film of the compound containing diphenylamino groups. The intermolecular charge transfer is induced in the film of carbazolyl-containing compound. The derivative of pentaphenylbenzene and diphenylamine exhibits higher hole drift mobility (2.4·10 cm/V·s at the electric field of 5.5·10 V/cm) and by 0.1 eV lower ionization potential than the carbazolyl-containing compound. Both the compounds were utilized as hole-transporting materials in a series of organic light emitting diodes (OLEDs) based on of thermally activated delayed fluorescence. With the maximum values of external quantum efficiency of 25.9 % and power efficiency of 43.4 lm/W, OLEDs containing the layers of the synthesized compounds outperformed the device based on TCTA by 4 %, without the change in spectral properties. Variable angle spectroscopic ellipsometry revealed the moderate average roughness of the films of the compound deposited by the thermal vacuum evaporation technique with an arithmetic mean deviation of not more than 0.8 nm. The prominent hole transport characteristics of the compounds make them good candidates for utilization in optoelectronic devices.
PubMed: 38943758
DOI: 10.1016/j.saa.2024.124713 -
Journal of Environmental Management Jun 2024Microplastics (MPs) have been found in remote high-altitude areas, but the main source and migration process remained unclear. This work explored the characteristics and...
Microplastics (MPs) have been found in remote high-altitude areas, but the main source and migration process remained unclear. This work explored the characteristics and potential sources of MPs in the Yarlung Tsangpo River Basin. The average abundances of MPs in water, sediment, and soil samples were 728.26 ± 100.53 items/m, 43.16 ± 5.82 items/kg, and 61.92 ± 4.29 items/kg, respectively, with polypropylene and polyethylene as the main polymers. The conditional fragmentation model revealed that the major source of MPs lower than 4000 m was human activities, while that of higher than 4500 m was atmospheric deposition. Community analysis was further conducted to explore the migration process and key points of MPs among different compartments in the basin. It was found that Lhasa (3600 m) and Shigatse (4100 m) were vital sources of MPs inputs in the midstream and downstream, respectively. This work would provide new insights into the fate of MPs in high-altitude areas.
PubMed: 38943743
DOI: 10.1016/j.jenvman.2024.121623 -
Biomacromolecules Jun 2024Rapid proliferation and a faster rate of glycolysis in cancer cells often result in an elevated local temperature (40-43 °C) at the tumor site. Nanoparticles prepared...
Rapid proliferation and a faster rate of glycolysis in cancer cells often result in an elevated local temperature (40-43 °C) at the tumor site. Nanoparticles prepared from polymers with two lower critical solution temperatures (LCSTs) can be utilized to take advantage of this subtle temperature elevation to deliver anticancer drugs preferably to the cancer cells, thereby enhancing the overall therapeutic efficacy and reducing side effects. In this direction, we synthesized -vinyl-2-pyrrolidone (NVP) and substituted NVP (sub-NVP: C-NVP, C-NVP)-based polymers with precisely controlled LCSTs by varying the ratio of NVP and sub-NVP. The first LCST (LCST1) was kept below 37 °C to promote self-assembly, drug loading, and structural stability in physiological conditions and the second LCST (LCST2) was in the range of 40-43 °C to ensure mild hyperthermia-induced drug release. Additionally, covalent attachment of tetraphenylethylene (TPE, AIEgen) resulted in aggregation-induced emission in thermoresponsive micellar nanoparticles in which TPE acted as a Förster Resonance Energy Transfer (FRET) pair with the loaded anticancer drug doxorubicin (DOX). Tracking of FRET-induced fluorescence recovery of TPE molecules was utilized to confirm the real-time thermoresponsive release of DOX from nanoparticles and eventual localization of TPE in the cytoplasm and DOX in the nucleus. cellular studies such as cytotoxicity, cellular uptake, and thermoresponsive drug release showed that the DOX-loaded polymeric nanoparticles were nontoxic to normal cells (HEK-293) but significantly more effective in cancer cells (MCF-7) at 40 °C. To our knowledge, this is the first report of preferential delivery of anticancer drugs only by exploiting the slightly elevated temperature of cancer cells.
PubMed: 38943659
DOI: 10.1021/acs.biomac.4c00572 -
Langmuir : the ACS Journal of Surfaces... Jun 2024Methylammonium lead halide perovskites with highly efficient pure-color or white-light generation have gained increasing scientific interest and promote the development...
Methylammonium lead halide perovskites with highly efficient pure-color or white-light generation have gained increasing scientific interest and promote the development of a great commercial opportunity in displays, lighting, and other applications. However, the poor stabilities, lead toxicity, and unfriendly solvents and ligands in the growth process severely restrict their commercial application. Here, we proposed a green method for preparing uniform and stable polymer-encapsulated photoluminescence (PL) tunable CHNHPbBrCl NC thin films at room temperature. Utilizing the swelling effect between alcohol compounds and organic polymers and the ionization of NaCl in methanol solution, the anion exchange process can be achieved rapidly within 7 min. Moreover, the PL wavelengths of the CHNHPbBrCl NCs films were precisely tuned with steps as fine as 2 nm. Experimental results showed that NaCl dissolved in methanol solution can form Cl(CHOH), which brings ionized Cl into the polymer-encapsulated CHNHPbBr NCs film for CHNHPbBrCl NCs film growth. Based on the swelling and anion exchange dynamics, a modified NaCl-CHOH-MABr solution system was developed to trigger CHNHPbBrCl NCs film PL emission tuning from 528 to 463 nm with several-fold intensity enhancement. The realization of precisely controlled photoluminescence from the perovskite nanocrystal film would have wide applications in the optical and imaging fields.
PubMed: 38943597
DOI: 10.1021/acs.langmuir.4c01505 -
Molekuliarnaia Biologiia 2024CRISPR/Cas systems are perspective molecular tools for targeted manipulation with genetic materials, such as gene editing, regulation of gene transcription, modification...
CRISPR/Cas systems are perspective molecular tools for targeted manipulation with genetic materials, such as gene editing, regulation of gene transcription, modification of epigenome etc. While CRISPR/Cas systems proved to be highly effective for correcting genetic disorders and treating infectious diseases and cancers in experimental settings, clinical translation of these results is hampered by the lack of efficient CRISPR/Cas delivery vehicles. Modern synthetic nanovehicles based on organic and inorganic polymers have many disadvantages, including toxicity issues, the lack of targeted delivery, and complex and expensive production pipelines. In turn, exosomes are secreted biological nanoparticles that exhibit high biocompatibility, physico-chemical stability, and the ability to cross biological barriers. Early clinical trials found no toxicity associated with exosome injections. In the recent years, exosomes have been considered as perspective delivery vehicles for CRISPR/Cas systems in vivo. The aim of this study was to analyze the efficacy of CRISPR/Cas stochastic packaging into exosomes for several human cell lines. Here, we show that Cas9 protein is effectively localized into the compartment of intracellular exosome biogenesis, but stochastic packaging of Cas9 into exosomes turns to be very low (~1%). As such, stochastic packaging of Cas9 protein is very ineffective and cannot be used for gene editing purposes. Developing novel tools and technologies for loading CRISPR/Cas systems into exosomes is needed.
Topics: Exosomes; Humans; CRISPR-Cas Systems; Gene Editing; CRISPR-Associated Protein 9
PubMed: 38943588
DOI: No ID Found -
ACS Applied Materials & Interfaces Jun 2024Biofilm-associated infections remain a tremendous obstacle to the treatment of microbial infections globally. However, the poor penetrability to a dense extracellular...
Biofilm-associated infections remain a tremendous obstacle to the treatment of microbial infections globally. However, the poor penetrability to a dense extracellular polymeric substance matrix of traditional antibacterial agents limits their antibiofilm activity. Here, we show that nanoaggregates formed by self-assembly of amphiphilic borneol-guanidine-based cationic polymers (BGN-) possess strong antibacterial activity and can eliminate mature () biofilms. The introduction of the guanidine moiety improves the hydrophilicity and membrane penetrability of BGN-. The self-assembled nanoaggregates with highly localized positive charges are expected to enhance their interaction with negatively charged bacteria and biofilms. Furthermore, nanoaggregates dissociate on the surface of biofilms into smaller BGN- polymers, which enhances their ability to penetrate biofilms. BGN- nanoaggregates that exhibit superior antibacterial activity have the minimum inhibitory concentration (MIC) of 62.5 μg·mL against and eradicate mature biofilms at 4 × MIC with negligible hemolysis. Taken together, this size-variable self-assembly system offers a promising strategy for the development of effective antibiofilm agents.
PubMed: 38943568
DOI: 10.1021/acsami.4c02818 -
Bratislavske Lekarske Listy 2024To create a new mucoadhesive dosage form based on PluronicF127 followed by transformation into a gel form upon intranasal administration for targeted delivery to brain...
OBJECTIVES
To create a new mucoadhesive dosage form based on PluronicF127 followed by transformation into a gel form upon intranasal administration for targeted delivery to brain tissueMETHODS: Citicoline, cytidine diphosphocholine, designated as CDP-choline, was purchased as a white powder with the molecular weight of 510.31 g/mol. The triblock copolymers of polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (PEG-PPG-PEG), branded as Pluronic F127, was used.
RESULTS
When instilled into the nasal cavity, Pluronic F127 for intranasal administration is transformed into a gel that remains retained for 45-55 minutes, which promotes better penetration of drugs into the brain tissue.
CONCLUSION
The polymer's gelling and adhesive properties performed well, which is crucial for further research at the preclinical stage (Tab. 1, Fig. 5, Ref. 28).
Topics: Administration, Intranasal; Poloxamer; Brain; Drug Delivery Systems; Animals; Cytidine Diphosphate Choline; Gels; Polyethylene Glycols; Nasal Mucosa
PubMed: 38943505
DOI: 10.4149/BLL_2024_67