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Journal of Biomaterials Science.... Jul 2024Cancer is ranked among the top causes of mortality throughout the world. Conventional therapies are associated with toxicity and undesirable side effects, rendering them... (Review)
Review
Cancer is ranked among the top causes of mortality throughout the world. Conventional therapies are associated with toxicity and undesirable side effects, rendering them unsuitable for prolonged use. Additionally, there is a high occurrence of resistance to anticancer drugs and recurrence in certain circumstances. Hence, it is essential to discover potent anticancer drugs that exhibit specificity and minimal unwanted effects. Curcumin, a polyphenol derivative, is present in the turmeric plant ( L.) and has chemopreventive, anticancer, radio-, and chemo-sensitizing activities. Curcumin exerts its anti-tumor effects on cancer cells by modulating the disrupted cell cycle through p53-dependent, p53-independent, and cyclin-dependent mechanisms. This review provides a summary of the formulations of curcumin based on nanospheres, since there is increasing interest in its medicinal usage for treating malignancies and tumors. Nanospheres are composed of a dense polymeric matrix, and have a size ranging from 10 to 200 nm. Lactic acid polymers, glycolic acid polymers, or mixtures of them, together with poly (methyl methacrylate), are primarily used as matrices in nanospheres. Nanospheres are suitable for local, oral, and systemic delivery due to their minuscule particle size. The majority of nanospheres are created using polymers that are both biocompatible and biodegradable. Previous investigations have shown that the use of a nanosphere delivery method can enhance tumor targeting, therapeutic efficacy, and biocompatibility of different anticancer agents. Moreover, these nanospheres can be easily taken up by mammalian cells. This review discusses the many curcumin nanosphere formulations used in cancer treatment.
PubMed: 38958210
DOI: 10.1080/09205063.2024.2371186 -
Nanotoxicology Jul 2024Plastic pollution has become a major environmental concern, and various plastic polymers are used daily. A study was conducted to examine the toxic effects of...
Plastic pollution has become a major environmental concern, and various plastic polymers are used daily. A study was conducted to examine the toxic effects of polyethylene terephthalate (PET) nanoplastics (NPLs) on Drosophila melanogaster. We have successfully synthesized PET NPLs and characterized using DLS, Zeta potential, TEM, HRTEM, SAED, XRD, FTIR, and Raman spectroscopy to gain crucial insights into the structure and properties. We fed PET NPLs to Drosophila to assess toxicity. ROS was quantified using DCFH-DA and NBT, and the nuclear degradation was checked by DAPI staining. Quantification of protein and activity of antioxidant enzymes like SOD, catalase depicted the adverse consequences of PET NPLs exposure. The dorsal side of the abdomens, eyes, and wings were also defective when phenotypically analyzed. These results substantiate the genotoxic and cytotoxic impact of nanoplastics. Notably, behavioral observations encompassing larval crawling and climbing of adults exhibit normal patterns, excluding the presence of neurotoxicity. Adult Drosophila showed decreased survivability, and fat accumulation enhanced body weight. These findings contribute to unraveling the intricate mechanisms underlying nanoplastic toxicity and emphasize its potential repercussions for organismal health and ecological equilibrium.
PubMed: 38958196
DOI: 10.1080/17435390.2024.2368004 -
Langmuir : the ACS Journal of Surfaces... Jul 2024The antifouling properties of conductive polymers have received extensive attention for biosensor and bioelectronic applications. Polyethylene glycol (PEG) is a...
The antifouling properties of conductive polymers have received extensive attention for biosensor and bioelectronic applications. Polyethylene glycol (PEG) is a well-known antifouling material, but the controlled regulation of the surface topography of PEG without a template remains a challenge. Here, we show a columnar structure antifouling conductive polymer brush with enhanced antifouling properties and considerable conductivity. The method involves synthesizing the 3,4-ethylenedioxythiophene monomer modified with azide (EDOT-N), the electropolymerization of PEDOT-N, and the in situ growth of PEG polymer brushes on PEDOT through double-click reactions. The resultant columnar structure polymer brush exhibits high electrical conductivity (3.5 Ω·cm), ultrahigh antifouling property, electrochemical stability (capacitance retention was 93.8% after 2000 cycles of CV scans in serum), and biocompatibility.
PubMed: 38957955
DOI: 10.1021/acs.langmuir.4c02180 -
Langmuir : the ACS Journal of Surfaces... Jul 2024Hydrogel microspheres are biocompatible materials widely used in biological and medical fields. Emulsification and stirring are the commonly used methods to prepare...
Hydrogel microspheres are biocompatible materials widely used in biological and medical fields. Emulsification and stirring are the commonly used methods to prepare hydrogels. However, the size distribution is considerably wide, the monodispersity and the mechanical intensity are poor, and the stable operation conditions are comparatively narrow to meet some sophisticated applications. In this paper, a T-shaped stepwise microchannel combined with a simple side microchannel structure is developed to explore the liquid-liquid dispersion mechanism, interfacial evolution behavior, satellite droplet formation mechanism and separation, and the eventual successful synthesis of dextran hydrogel microspheres. The effect of the operation parameters on droplet and microsphere size is comprehensively studied. The flow pattern and the stable operation condition range are given, and mathematical prediction models are developed under three different flow regimes for droplet size prediction. Based on the stable operating conditions, a microdroplet-based method combined with UV light curing is developed to synthesize the dextran hydrogel microsphere. The highly uniform and monodispersed dextran microspheres with good mechanical intensity are synthesized in the developed microfluidic platform. The size of the microsphere could be tuned from 50 to 300 μm with a capillary number in the range of 0.006-0.742. This work not only provides a facile method for functional polymeric microsphere preparation but also offers important design guidelines for the development of a robust microreactor.
PubMed: 38957947
DOI: 10.1021/acs.langmuir.4c00649 -
The Journal of Physical Chemistry. A Jul 2024Of late, siloxane-containing vitrimers have gained significant interest due to their fast dynamic characteristics over a reasonable temperature range (180-220 °C),...
Of late, siloxane-containing vitrimers have gained significant interest due to their fast dynamic characteristics over a reasonable temperature range (180-220 °C), making them well-suited for diverse applications. The exchange reaction pathway in the siloxane vitrimers is accountable for the covalent adaptive network, with the reaction's effectiveness being regulated by either organic or organometallic catalysts. However, directly studying the exchange reaction pathway in the bulk phase using experimental approaches is challenging because of the intricate and interconnected structure of these vitrimers. Here, we perform comprehensive density functional theory (DFT) and experimental investigations to discover the detailed catalytic efficacy of siloxane exchange and provide direction for the reaction process using a 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) catalyst. The calculated transition barrier energy and catalytic efficiency of hexamethyldisiloxane and dihydroxy-dimethylsilane exchange derived from the nudged elastic band with transition-state calculations strongly agree with the experimental findings. In addition, Fukui indices, along with partial charges, are employed to evaluate the nucleophilic and electrophilic behaviors of silanol and siloxane molecules. Our analysis revealed that by utilizing the Fukui indices of both the acid and the base, we can make an approximate estimation of the respective kinetics of the S2 process in the siloxane exchange reaction mechanism. These findings establish a foundation for comprehending a crucial aspect of the exchange mechanism in siloxane vitrimer systems and could aid in the development of novel catalysts.
PubMed: 38957945
DOI: 10.1021/acs.jpca.4c01394 -
Green Chemistry : An International... Jul 2024Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining...
Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining processes. Most structural knowledge about such humins is based on synthetic model humins prepared at lab-scale from typical carbohydrate(-derived) compounds. Here, we report the first extensive characterisation study of an industrial humin. The soluble humin was generated from pilot plant-scale methanolic cyclodehydration of D-fructose to 5-methoxymethyl-2-furfural (MMF), as part of the Avantium YXY® process to produce FDCA. Purification of the industrial humin followed by fractionation allowed isolation of a water-insoluble, high molecular weight fraction (WIPIH) and a water-soluble, low-to-middle molecular weight soluble fraction (WES). Characterisation by elemental analysis, thermogravimetry, IR and NMR spectroscopy and size exclusion chromatography provided a detailed picture of the humin structure in both fractions. Aided by a comprehensive NMR spectral library of furanic model compounds, we identified the main furanic building blocks and inter-unit linkages and propose a structure for this industrial humin sample. The WIPIH and WES fractions were found to be composed of furanic rings interconnected by short aliphatic chains containing a wide range of functionalities including alcohols, ethers, carboxylic acids, esters, aldehydes and ketones. The low level of crosslinking and high functional group content of the industrial humin differ from the more extensively studied, (highly over-)condensed synthetic model humins, towards which they can be considered intermediates. The structural and compositional insights into the nature of an actual industrial humin open up a broad spectrum of valorisation opportunities.
PubMed: 38957875
DOI: 10.1039/d4gc00429a -
Catalysis Science & Technology Jul 2024X-ray absorption spectroscopy (XAS) has been central to the study of the Phillips polymerization catalyst (CrO/SiO). As Cr K-edge XAS signatures are sensitive to the...
Influence of strong π-acceptor ligands on Cr-K-edge X-ray absorption spectral signatures and consequences for the interpretation of surface sites in the Phillips catalyst.
X-ray absorption spectroscopy (XAS) has been central to the study of the Phillips polymerization catalyst (CrO/SiO). As Cr K-edge XAS signatures are sensitive to the oxidation state, geometry and types of ligands on surface (active) sites, the superposition of these effects makes their interpretation challenging. Notably, CO has been particularly used as a reductant to generate low valent Cr sites from CrO/SiO and as a structural IR probe for analysing reduced Cr surface sites. Hence, it is essential to establish a solid understanding of the spectroscopic impact of CO on low-valent Cr sites. We thus built a series of fully characterized low-valent Cr molecular compounds bearing isoelectronic isocyanide ligands in place of CO, with the goal of understanding the effect of the coordination of π-acceptor ligands on the XANES signature of Cr sites. Cr K-edge spectra supplemented with DFT calculations elucidate the effect of the coordination of π-acceptor ligands on XAS signatures, giving a sharp resonance at the white line while modifying the fine structure due to short Cr-C distances and stability of low-spin Cr(ii/iii) species. The isocyanide references allow the deconvolution of the XAS spectra of the reduced CrO/SiO catalyst by evaluating the types of surface species and relative amounts of bound CO at different CO pressures and temperatures.
PubMed: 38957731
DOI: 10.1039/d3cy01692g -
Environmental Science. Advances Jul 2024In this study, we evaluated the suitability of elutriation, a method successfully employed in the extraction of microplastics from marine sediments, for the extraction...
In this study, we evaluated the suitability of elutriation, a method successfully employed in the extraction of microplastics from marine sediments, for the extraction of microplastics from freshwater and terrestrial soils. Five soils were sampled throughout Oklahoma, USA in order to capture a range of sand, silt, clay, and organic matter composition. Each soil was subjected to microplastic extraction with and without elutriation, followed by digestion in 7.5% NaOCl, and then flotation in 6 M ZnCl. The mass of each soil was measured after elutriation to determine sample mass reduction, and multiple methods including fluorescence imaging and automated particle counting through ImageJ, Attenuated Total Reflectence-Fourier Transfor Infrared Spectroscopy (ATR-FTIR), and Pyrolysis-coupled Gas Chromatography/Mass Spectrometry (py-GC/MS) were used to determine microplastic quantity, mass, and characteristics. -test was used to check for statistically-significant differences between methods in terms of mass or particle quantity. For all tested soils, elutriation resulted in greater sample mass reduction than non-elutriated samples, and was between 59.0-97.3% for the tested soils. Furthermore, no statistically significant ( < 0.05) differences were observed in particle quantification or polymer mass between methods, and no differences were observed for polymer or size distribution. Additionally, 33% more polymers were positively identified ( = 70%) by ATR-FTIR analysis in elutriated samples compared to non-elutriated soils. The mass reduction provided by elutriation allows for the processing of larger sample volumes, leading to greater accuracy and sensitivity in detecting microplastics. As such, we recommend elutriation be performed as a pretreatment step to extract microplastics from soils.
PubMed: 38957706
DOI: 10.1039/d4va00087k -
Improved Electrosynthesis of Biomass Derived Furanic Compounds via Nitroxyl Radical Redox Mediation.Chem & Bio Engineering Jun 2024Biomass is an abundantly available, underutilized feedstock for the production of bulk and fine chemicals, polymers, and sustainable and biodegradable plastics that are...
Biomass is an abundantly available, underutilized feedstock for the production of bulk and fine chemicals, polymers, and sustainable and biodegradable plastics that are traditionally sourced from petrochemicals. Among potential feedstocks, 2,5-furan dicarboxylic acid (FDCA) stands out for its potential to be converted to higher-value polymeric materials such as polyethylene furandicarboxylate (PEF), a bio-based plastic alternative. In this study, the sustainable, electrocatalytic oxidation of stable furan molecule 2,5-bis(hydroxymethyl)furan (BHMF) to FDCA is investigated using a variety of TEMPO derivative electrocatalysts in a mediated electrosynthetic reaction. Three TEMPO catalysts (acetamido-TEMPO, methoxy-TEMPO, and TEMPO) facilitate full conversion to FDCA in basic conditions with >90% yield and >100% Faradaic efficiency. The remaining three TEMPO catalysts (hydroxy-TEMPO, oxo-TEMPO, and amino-TEMPO) all perform intermediate oxidation of BHMF in basic conditions but do not facilitate full conversion to FDCA. On the basis of pH studies completed on all TEMPO derivatives to assess their electrochemical reversibility and response to substrate, pH and reversibility play significant roles in the catalytic ability of each catalyst, which directly influences catalyst turnover and product formation. More broadly, this study also highlights the importance of an effective and rapid electroanalytical workflow in mediated electrosynthetic reactions, demonstrating how voltammetric catalyst screening can serve as a useful tool for predicting the reactivity and efficacy of a catalyst-substrate electrochemical system.
PubMed: 38957543
DOI: 10.1021/cbe.4c00034 -
The Journal of Physical Chemistry. C,... Jun 2024Dodecane-capped silicon nanocrystals (NCs) were synthesized by using a low-temperature (800-1100 °C) polymer variant of traditional hydrogen silsesquioxane thermal...
Dodecane-capped silicon nanocrystals (NCs) were synthesized by using a low-temperature (800-1100 °C) polymer variant of traditional hydrogen silsesquioxane thermal disproportionation. Highly crystalline Si NCs having tunable diameters (3.0-6.7 nm) and thus photoluminescence (PL) peaks (1.68-1.29 eV) were attained via changes in the maximum annealing temperature. Modifications in the NC band structure with diameter were explored by comparison of emission with absorption spectra obtained from diffuse reflectance spectroscopy. Large apparent energy shifts between onsets and PL were noted, being significant for smaller NCs (≤∼4.0 nm). This, along with comparatively "softer" onsets, is commensurate with density of states elongation around PL peaks associated with increasing confinement predicted for indirect semiconductor nanostructures. Tauc analyses of absorption additionally revealed three distinguishable optical transitions in all NCs: attributed to indirect Γ-Δ in lower energy ranges (likely the emission progenitor), indirect Γ-L overtaken by quasi-direct Γ-X wave function mixing for NC diameters ≤∼4.0 nm within the midenergy regime, and direct Γ-Γ transitions at energies nearing and above ∼3 eV.
PubMed: 38957369
DOI: 10.1021/acs.jpcc.4c01462