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ACS Applied Polymer Materials Jun 2024Food smart packaging has emerged as a promising technology to address consumer concerns regarding food conservation and food safety. In this context, we report the...
Food smart packaging has emerged as a promising technology to address consumer concerns regarding food conservation and food safety. In this context, we report the rational design of azide-containing pyranoflavylium-based pH-sensitive dye for subsequent click chemistry conjugation toward a chitosan-modified alkyne. The chitosan-pyranoflavylium conjugate was characterized by infrared (ATR-FTIR), ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) spectroscopies, and dynamic light scattering (DLS), as well as its thermodynamic parameters related to their pH-dependent chromatic features. The fabrication of thin-films through electrostatic-driven layer-by-layer (LbL) assembly technology was first screened by quartz crystal microbalance with dissipation monitoring (QCM-D) onto gold substrates, and then free-standing (FS) multilayered membranes from polypropylene substrate were obtained using a homemade automatic dipping robot. The membranes' characterization included morphology analysis and thickness evaluation, assessed by scanning electron microscopy (SEM), pH-responsive color change performance tests using buffer solutions at different pH levels, and biogenic amines-enriched model solutions, demonstrating the feasibility and effectiveness of the chitosan-pyranoflavylium/alginate biomembranes for food spoilage monitoring. This work provides insights toward the development of innovative pH-responsive smart biomaterials for advanced and sustainable technological packaging solutions, which could significantly contribute to ensuring food safety and quality, while reducing food waste.
PubMed: 38903401
DOI: 10.1021/acsapm.4c01085 -
RSC Advances Jun 2024Tracking hypoxic environments and changes in oxygen levels contribute to the elucidation of pathological mechanisms. In this study, we attempted to design molecular...
Tracking hypoxic environments and changes in oxygen levels contribute to the elucidation of pathological mechanisms. In this study, we attempted to design molecular probes that can be activated to show fluorescence under hypoxic conditions and that can move to specific cell organelles. Considering that azide groups were selectively reduced to primary amines by reductases under hypoxic conditions, we prepared Hoechst and fluorophore Cy-5 derivatives with azide groups (Hoechst-N and Cy-N) as hypoxia probes. Hoechst-N and Cy-N showed weak fluorescence, but once activated in the cytosol of hypoxic cells, they exhibited robust fluorescence and then moved to their target organelles, the cell nucleus and mitochondria. In addition, when these probes were administered to the cells in the proper sequence, each probe was activated in response to the intracellular oxygen concentration at that point and exhibited oxygen concentration-dependent fluorescence at the target organelle. By measuring the fluorescence intensity of the cell nucleus and mitochondria, we successfully traced the history of changes in intracellular oxygen levels. Thus, we achieved tracking and recording of oxygen status in the cells.
PubMed: 38895527
DOI: 10.1039/d4ra01625d -
Materials (Basel, Switzerland) Jun 2024We report a synthesis of well-defined AB and AB miktoarm star-shaped polymers where -dimethylaminoethyl methacrylate (DMAEMA) and various cyclic esters such as...
We report a synthesis of well-defined AB and AB miktoarm star-shaped polymers where -dimethylaminoethyl methacrylate (DMAEMA) and various cyclic esters such as ε-caprolactone (ε-CL), lactide (LA) and glycolide (GA) were used for the synthesis. Miktopolymers were obtained by simultaneously carrying out atom transfer radical polymerization (ATRP) of DMAEMA, ring-opening polymerization (ROP) of cyclic esters, and reaction between the azide group in gluconamide-based (GLBr-Az) or lactonamide-based (GLBr-Az) ATRP initiators and 4-pentyn-1-ol. The relatively low dispersity indices of the obtained miktoarm stars (Đ = 1.2-1.6) indicate that control over the polymerization processes was sustained despite almost complete monomers conversions (83-99%). The presence of salts from phosphate-buffered saline (PBS) in polymer solutions affects the phase transition, increasing cloud point temperatures (T) values. The critical aggregation concentration (CAC) values increased with a decreasing number of average molecular weights of the hydrophobic fraction. Hydrolytic degradation studies revealed that the highest reduction of molecular weight was observed for polymers with PCL and PLGCL arm. The influence of the composition on the miktopolymers hydrophilicity was investigated via water contact angle (WCA) measurement. Thermogravimetric analysis (TGA) disclosed that the number of arms and their composition in the miktopolymer affects its weight loss under the influence of temperature.
PubMed: 38893949
DOI: 10.3390/ma17112684 -
Molecules (Basel, Switzerland) May 2024The synergistic effect of drug and gene delivery is expected to significantly improve cancer therapy. However, it is still challenging to design suitable nanocarriers...
The synergistic effect of drug and gene delivery is expected to significantly improve cancer therapy. However, it is still challenging to design suitable nanocarriers that are able to load simultaneously anticancer drugs and nucleic acids due to their different physico-chemical properties. In the present work, an amphiphilic block copolymer comprising a biocompatible poly(ethylene glycol) (PEG) block and a multi-alkyne-functional biodegradable polycarbonate (PC) block was modified with a number of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) side chains applying the highly efficient azide-alkyne "click" chemistry reaction. The resulting cationic amphiphilic copolymer with block and graft architecture (MPEG--(PC--PDMAEMA)) self-associated in aqueous media into nanosized micelles which were loaded with the antioxidant, anti-inflammatory, and anticancer drug quercetin. The drug-loaded nanoparticles were further used to form micelleplexes in aqueous media through electrostatic interactions with DNA. The obtained nanoaggregates-empty and drug-loaded micelles as well as the micelleplexes intended for simultaneous DNA and drug codelivery-were physico-chemically characterized. Additionally, initial in vitro evaluations were performed, indicating the potential application of the novel polymer nanocarriers as drug delivery systems.
Topics: Micelles; Quercetin; Methacrylates; DNA; Nylons; Drug Carriers; Humans; Polyethylene Glycols; Nanoparticles; Polymers
PubMed: 38893415
DOI: 10.3390/molecules29112540 -
International Journal of Molecular... Jun 2024SARS-CoV-2 is a highly infectious virus responsible for the COVID-19 pandemic. Therefore, it is important to assess the risk of SARS-CoV-2 infection, especially in...
SARS-CoV-2 is a highly infectious virus responsible for the COVID-19 pandemic. Therefore, it is important to assess the risk of SARS-CoV-2 infection, especially in persistently positive patients. Rapid discrimination between infectious and non-infectious viruses aids in determining whether prevention, control, and treatment measures are necessary. For this purpose, a method was developed and utilized involving a pre-treatment with 50 µM of propidium monoazide (PMAxx, a DNA intercalant) combined with a digital droplet PCR (ddPCR). The ddPCR method was performed on 40 nasopharyngeal swabs (NPSs) both before and after treatment with PMAxx, revealing a reduction in the viral load at a mean of 0.9 Log copies/mL (SD ± 0.6 Log copies/mL). Furthermore, six samples were stratified based on the Ct values of SARS-CoV-2 RNA (Ct < 20, 20 < Ct < 30, Ct > 30) and analyzed to compare the results obtained via a ddPCR with viral isolation and a negative-chain PCR. Of the five samples found positive via a ddPCR after the PMAxx treatment, two of the samples showed the highest post-treatment SARS-CoV-2 loads. The virus was isolated in vitro from both samples and the negative strand chains were detected. In three NPS samples, SARS CoV-2 was present post-treatment at a low level; it was not isolated in vitro, and, when detected, the strand was negative. Our results indicate that the established method is useful for determining whether the SARS-CoV-2 within positive NPS samples is intact and capable of causing infection.
Topics: Humans; SARS-CoV-2; Azides; Propidium; COVID-19; Viral Load; Nasopharynx; RNA, Viral; COVID-19 Nucleic Acid Testing; Polymerase Chain Reaction
PubMed: 38892344
DOI: 10.3390/ijms25116156 -
Nature Communications Jun 2024The generation of alkyl radical from C(sp)-H substrates via hydrogen atom abstraction represents a desirable yet underexplored strategy in alkylation reaction since...
The generation of alkyl radical from C(sp)-H substrates via hydrogen atom abstraction represents a desirable yet underexplored strategy in alkylation reaction since involving common concerns remain adequately unaddressed, such as the harsh reaction conditions, limited substrate scope, and the employment of noble metal- or photo-catalysts and stoichiometric oxidants. Here, we utilize the synergistic strategy of photoredox and hydrogen atom transfer (HAT) catalysis to accomplish a general and practical functionalization of unactived C(sp)-H centers with broad reaction scope, high functional group compatibility, and operational simplicity. A combination of validation experiments and density functional theory reveals that the N-centered radicals, generated from free N - H bond in a stepwise electron/proton transfer event, are the key intermediates that enable an intramolecular 1,5-HAT or intermolecular HAT process for nucleophilic carbon-centered radicals formation to achieve heteroarylation, alkylation, amination, cyanation, azidation, trifluoromethylthiolation, halogenation and deuteration. The practical value of this protocol is further demonstrated by the gram-scale synthesis and the late-stage functionalization of natural products and drug derivatives.
PubMed: 38876986
DOI: 10.1038/s41467-024-49337-3 -
Nature Communications Jun 2024Chiral 1,2,3-triazoles are highly attractive motifs in various fields. However, achieving catalytic asymmetric click reactions of azides and alkynes for chiral triazole...
Chiral 1,2,3-triazoles are highly attractive motifs in various fields. However, achieving catalytic asymmetric click reactions of azides and alkynes for chiral triazole synthesis remains a significant challenge, mainly due to the limited catalytic systems and substrate scope. Herein, we report an enantioselective azidation/click cascade reaction of N-propargyl-β-ketoamides with a readily available and potent azido transfer reagent via copper catalysis, which affords a variety of chiral 1,2,3-triazoles with up to 99% yield and 95% ee under mild conditions. Notably, chiral 1,5-disubstituted triazoles that have not been accessed by previous asymmetric click reactions are also prepared with good functional group tolerance.
PubMed: 38858346
DOI: 10.1038/s41467-024-49313-x -
Chemical Science Jun 2024Despite significant research, the mechanistic nuances of unusual reactivity at the air-water interface, especially in microdroplets, remain elusive. The likely...
Despite significant research, the mechanistic nuances of unusual reactivity at the air-water interface, especially in microdroplets, remain elusive. The likely contributors include electric fields and partial solvation at the interface. To reveal these intricacies, we measure the frequency shift of a well-defined azide vibrational probe at the air-water interface, while independently controlling the surface charge density by introducing surfactants. First, we establish the response of the probe in the bulk and demonstrate that it is sensitive to both electrostatics and hydrogen bonding. From interfacial spectroscopy we infer that the azide is neither fully hydrated nor in a completely aprotic dielectric environment; instead, it experiences an intermediate environment. In the presence of hydrogen bond-accepting sulphate surfactants, competition arises for interfacial water with the azide. However, the dominant influence stems from the electrostatic effect of their negative heads, resulting in a significant blue-shift. Conversely, for the positive ammonium surfactants, our data indicate a balanced interplay between electrostatics and hydrogen bonding, leading to a minimal shift in the probe. Our results demonstrate partial solvation at the interface and highlights that both hydrogen bonding and electrostatics may assist or oppose each other in polarizing a reactant, intermediate, or product at the interface, which is important for understanding and tuning interfacial reactivity.
PubMed: 38846382
DOI: 10.1039/d4sc01311e -
Heliyon Jun 2024Linseed is a valuable oilseed crop with huge therapeutic importance due to its high content of omega-3 fatty acids in the form of Alpha-linolenic acid (ALA). It is a...
Linseed is a valuable oilseed crop with huge therapeutic importance due to its high content of omega-3 fatty acids in the form of Alpha-linolenic acid (ALA). It is a self-pollinated crop with a low-yielding potential that restricts its improvement endeavors. To overcome low-yielding potential, individual and combination treatments of gamma rays and sodium azide were employed in widely grown linseed varieties. The results revealed a dose-dependent decline in seed germination, seedling height, pollen fertility, chlorophyll, and carotenoid contents and a dose-independent decline in carbonic anhydrase activity. Bio-physiological parameters decreased substantially in combination treatments compared to individual treatments of gamma rays and sodium azide. In contrast, lower doses of gamma rays, sodium azide, and their combinations effectively increased mean values of yield and yield-attributing traits in a few putative mutants. Such putative mutants represent a valuable genetic resource that could be used in future breeding programs for the genetic improvement of linseed and related medicinal plants.
PubMed: 38845881
DOI: 10.1016/j.heliyon.2024.e31329 -
Acta Crystallographica. Section E,... May 2024The title compound, tetra-ethyl-ammonium...
The title compound, tetra-ethyl-ammonium tri-azido-tri-μ-sulfido-[μ-(tri-methyl-sil-yl)aza-nediido][tris-(3,5-di-methyl-pyrazol-1-yl)hydro-borato]triiron(+2.33)molybdenum(IV), (CHN)[FeMoS(CHBN)(CHNSi)(N)] or (EtN)[(Tp*)MoFeS(μ-NSiMe)(N)] [Tp* = tris-(3,5-di-methyl-pyrazol-1-yl)hydro-bor-ate(1-)], crystallizes as needle-like black crystals in space group . In this cluster, the Mo site is in a distorted octa-hedral coordination model, coordinating three N atoms on the Tp* ligand and three μ-bridging S atoms in the core. The Fe sites are in a distorted tetra-hedral coordination model, coordinating two μ-bridging S atoms, one μ-bridging N atom from MeSiN, and another N atom on the terminal azide ligand. This type of heterometallic and heteroleptic single cubane cluster represents a typical example within the Mo-Fe-S cluster family, which may be a good reference for understanding the structure and function of the nitro-genase FeMo cofactor. The residual electron density of disordered solvent mol-ecules in the void space could not be reasonably modeled, thus the SQUEEZE [Spek (2015). . C, 9-18] function was applied. The solvent contribution is not included in the reported mol-ecular weight and density.
PubMed: 38845704
DOI: 10.1107/S2056989024004833