Due to industrialization and expansion of nanotechnology, ecosystem contamination by nanoparticles is likely. Overall, nanoparticles accumulate in environmental matrices and induce phytotoxicity, ...however future climate (elevated CO2 (eCO2)) may affect the distribution of nanoparticles in ecosystems and alter their impact on plants. In the current study, nickel oxide nanoparticles (NiO-NPs) with an average diameter of 54 nm were synthesized by chemical pericipitation method using Triton X-100 and characterized by scanning electron microscopy (SEM), UV-VIS spectroscopy and Fourier transform infrared spectroscopy (FTIR). We have investigated the impact of NiO-NPs at a concentration of 120 mg kg−1 soil, selected based on the results of a preliminary experiment, on accumulation of Ni ions in wheat (Triticum aestivum L.) and how that could influence plant growth, photosynthesis and redox homeostasis under two CO2 scenarios, ambient (aCO2, 400 ppm) and eCO2 (620 ppm). NiO-NPs alone reduced whole plant growth, inhibited photosynthesis and increased the levels of antioxidants. However, improved defense system was not enough to lessen photorespiration induced H2O2 accumulation and oxidative damage (lipid and protein oxidation). Interestingly, eCO2 significantly mitigated the phytotoxicity of NiO-NPs. Although, eCO2 did not affect Ni accumulation and translocation in wheat, it promoted photosynthesis and inhibited photorespiration, resulting in reduced ROS production. Moreover, it further improved the antioxidant defense system and maintained ASC/DHA and GSH/GSSG redox balances. Organ specific responses to NiO-NPs and/or eCO2 were indicated and confirmed by cluster analysis. Overall, we suggest that wheat plants will be more tolerant to NiO-NPs stress under future climate CO2.
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•NiO-NPs alone induced severe growth retardation and oxidative damage in wheat.•eCO2 did not affect accumulation of Ni in wheat, but antagonized its phytotoxicity.•eCO2 promoted photosynthesis and mitigated growth reduction induced by NiO-NPs.•eCO2 reduced ROS induced cellular damage and maintained redox homeostasis.•ROS content were reduced both at the production and detoxification level.
The study of biologically important Cu
2+
and S
2−
ions has drawn great attention in the recent years since an abnormal level of these ions is an indication for health impairment. Therefore, a ...reliable strategy for effective fluorescence determination of Cu
2+
and S
2−
ions was developed. Simply, the method based on economical plant-dependent thermolysis procedure for efficient green synthesis of water dispersible luminescent polyamine-based carbon dots (PA@C-dots) utilizes
Vitis vinifera
juice as precursor with a high quantum yield (32.1%) and good photo-stability. The fluorescent PA@C-dots were characterized by different spectroscopical, physical, and structural techniques. Furthermore, the synthesized PA@C-dots can be used as an efficient dual functional fluorescent probe for the sensitive and selective estimation of Cu
2+
and S
2−
ions. The incorporation of Cu
2+
ions and their adsorption on the surface of PA@C-dot skeleton leads to the respectable fluorescence quenching of C-dots (turn-off mode). The Cu
2+
-PA@C-dot was found to be sensitive to S
2−
ions. The addition of S
2−
recovers the fluorescence (turn-on mode) of Cu
2+
-PA@C-dots, thanks to its capacity for withdrawing Cu
2+
from the shell of PA@C-dots. Fluorescence quenching in the range of 0.07–60 μM Cu
2+
was obtained with LOD and LOQ of 0.02 and 0.066 μM, respectively. Sulfide detection provides linearity in the range of 0.8 to 95 μM with LOD and LOQ of 0.24 and 0.79 μM, respectively. The optimal excitation and emission wavelengths for all experiments are 435 nm and 498 nm, respectively. Experiment results elucidate that the proposed method is suitable for Cu
2+
and S
2−
ion detection in environmental water samples.
Graphical abstract
Green synthesis of polyamine-functionalized nanoprobe by thermolysis method from plant source as bifunctional sensing platform for determination of Cu
2+
and S
2−
in environmental water samples
•A novel ion pairing between IC and N@C-dots was proposed for the first time.•The interaction resulted in cyan blue color and quenching of N@C-dots fluorescence.•The nanoprobe exhibited good ...sensitivity and selectivity towards IC.•The application of nanoprobe was extended for analysis of IC in beverages.
Indigo carmine (IC) dye is hazardous and allergenic for humans even though it has been excessively used in a wide range of industries. Therefore, the quantitative determination of IC is still challenging. Herein, for the first time, we have developed fluorometric and colorimetric dual-mode nanoprobe derived from the ion-pair association complex between the negatively charged IC and positively charged N@C-dots in pH = 3.0. Consequently, the binding between N@C-dots and IC resulted in cyan blue and quenching of N@C-dots fluorescence. The dependence of the fluorescence response on IC concentrations was linear over the range of 0.73–10.0 µM (R2 = 0.9989) with LOD of 0.24 µM. On the other hand, the linearity of the colorimetric method ranged from 9.97 to 80.0 µM (R2 = 0.9986) with LOD of 3.3 µM. The sensor was applied for estimation of IC in fruit juice and soft drink without the need for exhaustive extraction steps.
Throughout decades, the intrinsic power of the immune system to fight pathogens has inspired researchers to develop techniques that enable the prevention or treatment of infections via boosting the ...immune response against the target pathogens, which has led to the evolution of vaccines. The recruitment of Lipid nanoparticles (LNPs) as either vaccine delivery platforms or immunogenic modalities has witnessed a breakthrough recently, which has been crowned with the development of effective LNPs-based vaccines against COVID-19. In the current article, we discuss some principles of such a technology, with a special focus on the technical aspects from a translational perspective. Representative examples of LNPs-based vaccines against cancer, COVID-19, as well as other infectious diseases, autoimmune diseases, and allergies are highlighted, considering the challenges and promises. Lastly, the key features that can improve the clinical translation of this area of endeavor are inspired.
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•Vaccines have come to the forefront as a key tool in the containment of pandemics.•LNPs are versatile vaccination tools, either as delivery vectors or adjuvants.•Principles of using LNPs in vaccines and their targeting strategies are discussed.•Model vaccines against cancer, COVID-19, and other contagions are highlighted.•Vaccines are used beyond contagions, such as in auto-immune diseases and allergies.
In recent decades, H
2
O
2
has been promoted as a health indicator because its moderate to high levels can cause some health problems. Herein, we developed a new fluorescent nanoprobe for rapid, ...selective and sensitive detection of H
2
O
2
. The fluorescent nanoprobe is composed of fluorescein dye (FLS) as a fluorescent probe and MnO
2
nanosheets (MnO
2
NS) as a quencher. In this study, H
2
O
2
can reduce MnO
2
NS in the synthesized composite and release FLS, causing sufficient recovery of fluorescent signal related to the concentration of H
2
O
2
. The nanoprobe, with
λ
ex
/
λ
em
at 495/515 nm, has a linear range of 0.04-30 μM, with a limit of detection (LOD) of 7.5 nM and a limit of quantitation (LOQ) of 21 nM. The mean relative standard deviation (RSD) was 2.6% and the applicability of the method was demonstrated by the determination of H
2
O
2
in water and cosmetic samples.
The fluorometric nanoprobe was fabricated
via
doping of fluorescein dye in MnO
2
nanosheets (FLS/MnO
2
NS)
via
facile co-precipitation method. It was used for analysis of H
2
O
2
in different matrices through liberation of FLS after reduction of MnO
2
NS.
Carbon dots doped with copper(II) and nitrogen (Cu,N@C-dots) were prepared and are shown to be viable fluorescent nanoprobe for pyrogallol (PGL) was developed for the first time. The reaction is ...based on (a) the complexation reaction between Cu,N@C-dots and catechol moiety, and (b) the generation of a quinone-like structure. Thus, the co-ordination complex formed between Cu(II) in C-dots and PGL results in quenching of the fluorescence of C-dots. In addition, the formation of a yellow color due to complex formation between the nanoprobe and Cu(II) allowed the colorimetric determination of PGL. The nanoprobe was prepared by thermal synthesis, using ethylenediaminetetraacetic acid salt and copper(II) chloride as sources for carbon, nitrogen and copper, respectively. The carbon dots were characterized by UV-VIS spectroscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy) and dynamic light scattering. Fluorescence drops linearly in the 0.15 to 70 μM PGL concentration range with a detection limit of 39 nM and a relative standard deviation of 1.8%. The optimal excitation and emission wavelengths are 370 nm and 428 nm, respectively. The colorimetric assay has a linear response at 325 nm absorption wavelengths in the 6 to 140 μM PGL concentration range with a detection limit of 1.8 μM and a 2.3% relative standard deviation.
Graphical abstract
Dual mode colorimetric and fluorimetric nanoprobe was designated for pyrolgallol determination based on complexation with copper(II)- and nitrogen-doped carbon dots.
Aluminum (Al) toxicity is a major constraint for crop production in acid soils. Therefore, looking for sustainable solutions to increase plant tolerance to Al toxicity is needed. Although several ...studies addressed the potential utilization of silica or silicon dioxide nanoparticles (SNPs) to ameliorate heavy metal phytotoxicity, the exact mechanisms underlying SNPs-induced stress tolerance are still unknown. The current study investigated how SNPs could mitigate Al toxicity in maize plants grown on acidic soil. The impact of Al alone or in combination with SNPs on Al accumulation and detoxification, plant growth, photosynthetic C assimilation and redox homeostasis has been investigated. Al accumulation in stressed-maize organs reduced their growth, decreased photosynthesis related parameters and increased production of reactive oxygen species, through induced NADPH oxidase and photorespiration activities, and cell damage. These effects were more pronounced in roots than in leaves. SNPs ameliorated Al toxicity at growth, physiological and oxidative damage levels. Co-application of SNPs significantly reduced the activities of the photorespiratory enzymes and NADPH oxidase. It stimulated the antioxidant defense systems at enzymatic (superoxide dismutase, catalase, ascorbate and glutathione peroxidases) and non-enzymatic (ascorbate, glutathione, polyphenols, flavonoids, tocopherols, and FRAP) levels. Moreover, SNPs increased organic acids accumulation and metal detoxification (i.e. glutathione-S-transferase activity) in roots, as a protective mechanism against Al toxicity. The SNPs induced-protective mechanisms was dependent on the applied Al concentration and acted in organ-specific manner. Overall, the current study suggests the promising application of SNPs as an innovative approach to mitigate Al phytotoxicity in acidic soils and provides a comprehensive view of the cellular and biochemical mechanisms underlying this mitigation capacity.
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•Aluminum (Al) reduced the growth and photosynthesis and induced oxidative stress in maize plants.•Nano-SiO2 (SNPs) did not affect Al accumulation but mitigated its phytotoxicity.•SNPs induced organic acid exudation by roots and metal detoxification activity.•SNPs reduced ROS production and improved ROS scavenging systems.•Maize responses to Al and SNPs were in a dose- and organ-specific manner.
Future climate CO2 (eCO2) and contamination with nano-sized heavy metals (HM-NPs) represent concurrent challenges threatening plants. The interaction between eCO2 and HM-NPs is rarely investigated, ...and no study has addressed their synchronous impact on the metabolism of the multifunctional stress-related metabolites, such as sugars and amino acids. Moreover, the characteristic responses of C3 and C4 plant systems to the concurrent impact of eCO2 and HM-NPs are poorly understood. Herein, we have assessed the impact of eCO2 (620 ppm) and/or HgO-NPs (100 mg/Kg soil) on growth, physiology and metabolism of sugars and amino acids, particularly proline, in C3 (wheat) and C4 (maize) plant systems. Under Hg-free conditions, eCO2 treatment markedly improved the growth and photosynthesis and induced sugars levels and metabolism (glucose, fructose, sucrose, starch, sucrose P synthase and starch synthase) in wheat (C3) only. In contrast, HgO-NPs induced the uptake, accumulation and translocation of Hg in wheat and to less extend in maize plants. Particularly in wheat, this induced significant decreases in growth and photosynthesis and increases in photorespiration, dark respiration and levels of tricarboxylic acid cycle organic acids. Interestingly, the co-application of eCO2 reduced the accumulation of Hg and recovered the HgO-NPs-induced effects on growth and metabolism in both plants. At stress defense level, HgO-NPs induced the accumulation of sucrose and proline, more in maize, via upregulation of sucrose P synthase, ornithine amino transferase, ∆1-pyrroline-5-carboxylate (P5C) synthetase and P5C reductase. The co-existence of eCO2 favored reduced sucrose biosynthesis and induced proline catabolism, which provide high energy to resume plant growth. Overall, despite the difference in their response to eCO2 under normal conditions, eCO2 induced similar metabolic events in C3 and C4 plants under stressful conditions, which trigger stress recovery.
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•Under HgO-NPs free conditions, the biofertilization impact of eCO2 is only evident in wheat (C3).•HgO-NPs increased Hg uptake, accumulation and translocation in the tested plants.•Maize plants (C4) were more tolerant to HgO-NPs toxicity than wheat.•HgO-NPs induced the accumulation of sucrose and proline, more in maize.•Coexistence of eCO2 with HgO-NPs reduced sucrose biosynthesis and induced proline catabolism in both plants.
Metal halide perovskites are promising candidates for use in light emitting diodes (LEDs), due to their potential for color tunable and high luminescence efficiency. While recent advances in ...perovskite-based light emitting diodes have resulted in external quantum efficiencies exceeding 12.4% for the green emitters, and infrared emitters based on 3D/2D mixed dimensional perovskites have exceeded 20%, the external quantum efficiencies of the red and blue emitters still lag behind. A critical issue to date is creating highly emissive and stable perovskite emitters with the desirable emission band gap to achieve full-color displays and white LEDs. Herein, we report the preparation and characterization of a highly luminescent and stable suspension of cubic-shaped methylammonium lead triiodide (CH3NH3PbI3) perovskite nanocrystals, where we synthesize the nanocrystals via a ligand-assisted reprecipitation technique, using an acetonitrile/methylamine compound solvent system to solvate the ions and toluene as the antisolvent to induce crystallization. Through tuning the ratio of the ligands, the ligand to toluene ratio, and the temperature of the toluene, we obtain a solution of CH3NH3PbI3 nanocrystals with a photoluminescence quantum yield exceeding 93% and tunable emission between 660 and 705 nm. We also achieved red emission at 635 nm by blending the nanocrystals with bromide salt and obtained perovskite-based light emitting diodes with maximum electroluminescent external quantum efficiency of 2.75%.
Accumulation of arsenic in plant tissues poses a substantial threat to global crop yields. The use of plant growth-promoting bacterial strains to mitigate heavy metal toxicity has been illustrated ...before. However, its potential to reduce plant arsenic uptake and toxicity has not been investigated to date. Here, we describe the identification and characterization of a Nocardiopsis lucentensis strain isolated from heavy metal contaminated soil. Inoculation with this bioactive actinomycete strain decreased arsenic root and shoot bioaccumulation in both C3 and C4 crop species namely barley and maize. Upon arsenate treatment, N. lucentensis S5 stimulated root citric acid production and the plant’s innate detoxification capacity in a species-specific manner. In addition, this specific strain promoted biomass gain, despite substantial tissue arsenic levels. Detoxification (metallothionein, phytochelatin, glutathione-S-transferase levels) was upregulated in arsenate-exposed shoot and roots, and this response was further enhanced upon S5 supplementation, particularly in barley and maize roots. Compared to barley, maize plants were more tolerant to arsenate-induced oxidative stress (less H2O2 and lipid peroxidation levels). However, barley plants invested more in antioxidative capacity induction (ascorbate-glutathione turnover) to mitigate arsenic oxidative stress, which was strongly enhanced by S5. We quantify and mechanistically discuss the physiological and biochemical basis of N. lucentensis-mediated plant biomass recovery on arsenate polluted soils. Our findings substantiate the potential applicability of a bactoremediation strategy to mitigate arsenic-induced yield loss in crops.
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•Nocardiopsis lucentensis was isolated from heavy metal polluted soil.•Compared to barley (C3), maize (C4) plants were more tolerant to arsenate (As) toxicity.•N. lucentensis fully restored (barley) and even enhanced (maize) plant biomass production.•Maize relies on citric acid-mediated soil As retention, which is induced by N. lucentensis.•In contrast, barley plants invested more in As detoxification and oxidative stress mitigation.
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