Impacts of surface chemistry of functional carbon nanodots on the plant growth

Pulmonary microbiota disruption by respiratory exposure to carbon quantum dots induces neuronal damages in mice

Given the fact that carbon quantum dots (CQDs) have been commercially produced in quantities, it is inevitable to make their ways into environment and interact closely with the public. Even though CQDs in the environment have been reported to damage the central nervous system, the underlying mechanisms of neurotoxic effects of CQDs following respiratory exposure is still not clear. Intranasal instilled CQDs, mimicking respiratory exposure, induces neurobehavioral impairments associated with neuronal cell death of ferroptosis and disulfidptosis that is regulated by metabolic reprogramming of glutathione and cysteine pathways in the cortex and hippocampus where CQDs were hardly accumulated. Therefore, further exploration found that dysbiosis in the lung microbiome was found specifically manipulated by CQDs, which correlated with systemic and neuroinflammatory responses, implicating a lung-brain axis other than gut-brain axis as a critical pathway through which microbiota dysbiosis may impact neurological health after respiratory exposure to CQDs. This study pioneers the exploration of the neurological consequences of inhaled CQDs in the environment through the regulation of microbiome-lung-brain axis, which is key in understanding the mechanistic link between CQDs exposure and neurotoxicity. The findings could develop potential strategies for mitigating the neurological effects of CQDs even other types of nanoparticles.

Recent Advances of Carbon Dots: Synthesis, Plants Applications, Prospects, and Challenges

Nanomaterials and nanotechnology have garnered significant attention in the realm of agricultural production. Carbon dots (CDs), as a class of nanomaterials, play a crucial role in the field of plant growth due to their excellent properties. This review aims to summarize recent achievements on CDs, focusing on their methods of preparation and applications in plants systems. The effects of CDs on seed germination, growth, photosynthesis, nutritional quality, and stress resistance were studied. It has been demonstrated that CDs can promote seed germination and growth, as well as improve photosynthetic efficiency, ultimately leading to increase plants yield. The nutritional quality of the plants treated with CDs was significantly improved. Specifically, the levels of essential mineral elements, vitamins, amino acids, and other constituents that are beneficial to human health increased notably. Additionally, CDs show positive effects on augmenting plant resistance against environmental stresses, such as drought conditions, heavy metal toxicity, and high salinity. Finally, the prospects and challenges of the application of CDs in plant systems are also discussed, which provide a scientific basis for the future application of CDs in agricultural production.

Unlocking Photosynthetic Potential: Harnessing Rosa roxburghii Derived Carbon Dots as Nanofertilizers for Enhanced Plant Growth

The synthesis of nanomaterials from renewable resources has emerged as an environmentally friendly alternative. This approach helps to reduce the use of chemical fertilizers in agricultural production, further reducing the potential harm to the ecosystem and effectively reducing the burden on the environment. In this work, we synthesized Rosa roxburghii derived carbon dots (CDs) using the microwave hydrothermal method (RR-CDs) and the electrolytic oxidation method (GRR-CDs), and the results showed that RR-CDs had a wider ultraviolet absorption range and emitted blue fluorescence. These properties make RR-CDs more effective as light-harvesting materials in plants, thus promoting photosynthesis. In the cultivation of lettuce, RR-CDs significantly enhanced both the biomass and the quality of the lettuce. In addition, compared to the control group, the chlorophyll content of lettuce treated with RR-CDs increased by 31.83%, the net photosynthetic rate increased by 60.76%, and the electron transport rate of photosystem II increased by 38.72%. Therefore, we found that the microwave hydrothermal method could bring better benefits, with a yield of up to 40.20% after just 2 h of reaction. RR-CDs promote photosynthesis by promoting light conversion and improving nutrient efficiency while also boasting the dual advantages of low cost and easy large-scale production, thus opening up avenues for sustainable agricultural production.

Synergistic promotion mechanism and structure-function relationship of nonmetallic atoms doped carbon nanodots driving Tagetes patula L. to remediate cadmium-contaminated soils

Phytoremediation is an economical and effective strategy to remove cadmium (Cd) from polluted environments. To improve its efficiency, nanotechnology has been proposed to collaborate with hyperaccumulators in the remediation of Cd-polluted soils. However, the intricate structure-function relationship and the underlying regulatory mechanisms by which nanomaterials regulate Cd migration and conversion within the soil-plant system remained unrevealed. In this study, functional carbon nanodots (FCNs) were modified by doping with nitrogen and (or) sulfur elements. The synthesized nonmetallic atoms-doped FCNs were utilized to investigate their structure-function relationship and the regulatory mechanisms underlying their role in the phytoremediation of Cd-polluted soils by Tagetes patula L. FCNs-based nanomaterials can regulate the migration and bioaccumulation of Cd in the soil-plant system, which exhibits an obvious structural dependency. Specifically, the synergistic application of sulfur doped FCNs and Tagetes patula L. had the highest Cd removal efficiency of 53.2 %, which was 20.1 % higher than Tagetes patula L. alone. The uptake and migration of Cd in the soil-plant system are regulated by FCNs-based nanomaterials through both direct and indirect mechanisms, involving interfacial reactions, plant physiology regulation and environmental influence. This study not only sheds light on the fate of FCNs-based nanomaterials and Cd in the soil-plant system, but also provides innovative nanotools for reinforcing phytoremediation efficiency in contaminated soils.

Functional carbon nanodots enhance tomato tolerance to zinc deficient soils: Mechanisms and structure-function relationships

Zinc (Zn) deficiency is a global problem disorder affecting both crops and humans. Herein, modified functional carbon nanodots (MFCNs) with various structures and characteristics were developed to regulate tomato yields and Zn migration in plant-soil systems affected by Zn deficiency through structure-function relationships. Sulfur-doped FCNs (S-FCNs), nitrogen-doped FCNs (N-FCNs), and nitrogen‑sulfur co-doped FCNs (N,S-FCNs) were hydrothermally modified using FCNs as precursors. Their regulatory effects on tomatoes growing in Zn-deficient alkaline soils were studied in pot culture experiments. Specifically, 8 mg kg-1 of FCNs and S-FCNs improved tomato yields by 132 % and 108 %, respectively, compared with the control. However, N-FCNs and N,S-FCNs showed no significant effect on yield compared with the control (P < 0.05). Moreover, the application of FCNs or S-FCNs significantly improved fruit quality and nutritional value, including Zn content (by 26.3 % and 22.0 %, respectively) and naturally occurring antioxidants (by 3.37- and 2.08-fold for lycopene, 1.31- and 1.18-fold for flavonoids, and 2.28- and 1.89-fold for phenolics, respectively; P < 0.05). Although N-FCNs and N,S-FCNs increased Zn contents, they inhibited the synthesis of naturally occurring antioxidants in fruits. Zn bioaccessibility, uptake, and transportation in plant-soil systems were regulated by MFCNs through both direct and indirect mechanisms, including ionic reactions, plant physiology, and environmental effects. MFCNs regulated plant tolerance to Zn deficiency not only by affecting root activity, redox homeostasis, micronutrient balance, chelator synthesis, genetic expression, and plant photosynthesis but also by influencing rhizosphere soil properties and the microbial environment. Based on their dual role as "plant growth regulators" and "soil conditioners", MFCNs may have general applicability in agriculture. This study highlights the behavior of MFCNs in plant-soil systems, providing innovative nanotools for enhancing Zn availability, crop stress resistance and environmental preservation in sustainable agriculture.

Luminous Insights: Harnessing Carbon Nanodots from Black Seed Powder via Pyrolysis for Bioimaging and Antifungal Investigations

This study delves into the fabrication of carbon nanodots (CNDs) through a bottom-up approach, utilizing black seed powder as the precursor material and employing the pyrolysis method. CNDs were synthesized across four distinct temperature settings. The investigation encompasses an extensive characterization of the CNDs, including optical and structural attributes. UV-visible and fluorescence spectroscopy were utilized to assess their optical properties, while FT-IR and XRD analyses confirmed their structural integrity. To elucidate size, shape, and nature, HR-TEM imaging was employed. Furthermore, the functional applications of the synthesized CNDs were explored. The material's antifungal potential was evaluated, and its viability for bioimaging was demonstrated by successfully labeling yeast cells with CNDs. This study underscores the multifaceted nature of CNDs, serving as a bridge between synthesis, comprehensive characterization, and practical applications. In summary, the investigation provides insights into the versatile applications of CNDs derived from black seed powder through pyrolysis. The study contributes to the understanding of their fundamental properties and establishes their potential for both antifungal treatments and cellular bioimaging.

The intrinsic and extrinsic mechanisms regulated by functional carbon nanodots for the phytoremediation of multi-metal pollution in soils

Functional carbon nanodots (FCNs) were currently demonstrated to regulate plant behavior in the agricultural and environmental areas. However, their regulation mechanisms on the interactions of plant-soil system during phytoremediation remain unrevealed. Here, Solanum nigrum L. was employed to explore the intrinsic and extrinsic mechanisms regulated by FCNs in the phytoremediation of Cd-Pb co-contaminated soils. The mediation of FCNs on metal removal and plant growth showed a hormesis manner, wherein the maximum induction effect was contributed by 15 mg kg-1 FCNs. Cd/Pb removal were enhanced by 8.5% and 31.6%, respectively. Moreover, FCNs reallocate metal distribution in plant by immobilized metals in roots and suppressed metal translocation to leaves. Improving plant growth (by 82.8% for root), stimulating plant hormesis, and activating plant detoxification pathways are the intrinsic mechanism for the phytoremediation smartly regulated by FCNs. Notably, FCNs induced soil enzyme activities that associated with soil nutrients recycling, up-regulated the microbial diversity and the soil immune system, and regulated S. nigrum L. to recruit beneficial microbials in the rhizosphere. The above-mentioned comprehensive improvement of soil micro-environment is the extrinsic mechanism regulated by FCNs. This study provides new insights to evaluate the interactions of nanomaterials with plant-soil system under soil contamination.

Protective role of fullerenol and arginine C60 fullerene against copper toxicity in cucumber

Copper (Cu), when in excess, is one of the most toxic and hazardous metals to all living organisms, including plants. Engineered nanomaterials have the potential for increasing crop protection. However, the protective role of fullerenes (carbon-based nanoparticles with wide application in various areas) against Cu toxicity in plants is, so far, understudied. The present study investigated whether fullerenes can potentially alleviate Cu toxicity in plants (Cucumis sativus L.). Two water-soluble fullerene C60 derivatives were examined: fullerenol [C60(OH)22-24] and arginine-functionalized fullerene [C60(C6H13N4O2)8H8], under controlled conditions using hydroponics. Plants treated with 15 μM of Cu exhibited typical symptoms of Cu toxicity: impaired growth, leaf chlorosis, reduced photosynthetic activity, nutritional imbalances, and enhanced lipid peroxidation. These symptoms were alleviated in the presence of fullerene derivatives with arginine C60 having the more pronounced effect. Improved cucumber Cu tolerance was attributable to Cu buffering in the root zone (roots and medium), which caused a dramatic decline in Cu transport towards leaves and the elimination of oxidative damage. The Cu removal efficacy of arginine C60 was much greater than that of fullerenol. These fullerenes acted in a dose-dependent manner and removed Cu selectively without significant modification of the bioavailability of other essential nutrients. Treatment with free arginine did not affect Cu immobilization or Cu toxicity. These results suggest that the surface chemistry of the fullerene core is important for the protection of plants under excessive Cu conditions. The information offered a new approach to preparing promising practical materials for alleviating Cu toxicity in plants with potential application in fields.

Physiological Functions of Carbon Dots and Their Applications in Agriculture: A Review

Carbon dots are carbon-based nanoparticles, which have the characteristics of a simple preparation process, photoluminescence, biocompatibility, an adjustable surface function, water solubility, and low-level toxicity. They are widely used in biological applications, such as imaging, biosensing, photocatalysis, and molecular transfer. They have also aroused great interest among researchers in agriculture, and there has been significant progress in improving crop growth and production. This review presents the physiological functions of carbon dots for crop growth and development, photosynthesis, water and nutrient absorption, and abiotic stress resistance and their applications in improving the ecological environment and agriculture as biosensors, and future application prospects and research directions of carbon dots in agriculture.

Efficacy of Carbon Nanodots and Manganese Ferrite (MnFe2O4) Nanoparticles in Stimulating Growth and Antioxidant Activity in Drought-Stressed Maize Inbred Lines

Despite being the third most-consumed crop, maize (Zea mays L.) is highly vulnerable to drought stress. The predominant secondary metabolite in plants is phenolic acids, which scavenge reactive oxygen species to minimize oxidative stress under drought stress. Herein, the effect of carbon nanodots (CND) and manganese ferrite (MnFe2O4) nanoparticles (NP) on the drought stress tolerance of maize has been studied. The experimental results revealed that the highest leaf blade length (54.0 cm) and width (3.9 cm), root length (45.2 cm), stem diameter (11.1 mm), root fresh weight (7.0 g), leaf relative water content (84.8%) and chlorogenic (8.7 µg/mL), caffeic (3.0 µg/mL) and syringic acid (1.0 µg/mL) contents were demonstrated by CND-treated (10 mg L-1) inbred lines (GP5, HW19, HCW2, 17YS6032, HCW3, HCW4, HW7, HCW2, and 16S8068-9, respectively). However, the highest shoot length (71.5 cm), leaf moisture content (83.9%), shoot fresh weight (12.5 g), chlorophyll content (47.3), and DPPH free radical scavenging activity (34.1%) were observed in MnFe2O4 NP-treated (300 mg L-1) HF12, HW15, 11BS8016-7, HW15, HW12, and KW7 lines, respectively. The results indicate that CND and MnFe2O4 NP can mitigate drought stress effects on different accessions of the given population, as corroborated by improvements in growth and physio-biochemical traits among several inbred lines of maize.

Sustainable agronomic response of carbon quantum dots on Allium sativum: Translocation, physiological responses and alternations in chromosomal aberrations

The revolutionary growth in the usage of carbon quantum dots (CQDs) in different areas have ultimately directed their discharge in the environment and further augmented the exposure of agricultural crops to these released particles. Therefore, the aim of current study is to evaluate the uptake, translocation and phytotoxicity of blue emissive CQDs on Allium sativum plant. The genotoxicity and cytotoxicity assessment of CQDs towards Allium sativum roots was estimated as function of three different concentrations. Considering the role of CQDs in promoting seed germination at 50 ppm concentration, a greenhouse experiment was performed to evaluate their effect on plant growth. Systematic investigations have shown the translocation of CQDs and their physiological response in terms of increased shoot length wherein P-CQDs exhibited more accumulation into Allium sativum parts. Our investigations unfold the opportunity to utilize Aegle marmelos fruit derived CQDs as a growth regulator in variety of other food plants.

Functional carbon nanodots improve soil quality and tomato tolerance in saline-alkali soils

High salinity and alkalinity of saline-alkali soil lead to soil deterioration, the subsequent osmotic stress and ion toxicity inhibited crops growth and productivity. In this research, 8 mg kg^-1 and 16 mg kg^-1 functional carbon nanodots (FCNs) can alleviate the adverse effects of saline-alkali on tomato plant at both seedling and harvest stages, thanks to their up-regulation effects on soil properties and plant physiological processes. On one hand, FCNs stimulate the plant potential of tolerance to saline-alkali and disease resistance through triggering the defense response of antioxidant system, enhancing the osmotic adjustment, promoting the nutrient uptake, transportation and utilization, and up-regulating the photosynthesis, thereby improve tomato growth and productivity in saline-alkali soils. On the other hand, FCNs application contributes to the improvement of soil physicochemical properties and fertilities, as well as decline soil salinity and alkalinity, which are related to plant growth and fruit quality. This research also focuses on the dose-dependent effects of FCNs on their regulation effects and toxicity to tomato growth under stress or non-stress. These findings recommend that FCNs could be applied as potential amendments to ameliorate the saline-alkali soil and improve the tomato tolerance and productivity in the Yellow River Delta.

Nanofertilizer Possibilities for Healthy Soil, Water, and Food in Future: An Overview

Conventional fertilizers and pesticides are not sustainable for multiple reasons, including high delivery and usage inefficiency, considerable energy, and water inputs with adverse impact on the agroecosystem. Achieving and maintaining optimal food security is a global task that initiates agricultural approaches to be revolutionized effectively on time, as adversities in climate change, population growth, and loss of arable land may increase. Recent approaches based on nanotechnology may improve in vivo nutrient delivery to ensure the distribution of nutrients precisely, as nanoengineered particles may improve crop growth and productivity. The underlying mechanistic processes are yet to be unlayered because in coming years, the major task may be to develop novel and efficient nutrient uses in agriculture with nutrient use efficiency (NUE) to acquire optimal crop yield with ecological biodiversity, sustainable agricultural production, and agricultural socio-economy. This study highlights the potential of nanofertilizers in agricultural crops for improved plant performance productivity in case subjected to abiotic stress conditions.

Effects of nano-TiO2 on the bioavailability and toxicity of bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) in developing zebrafish

Nanoparticles like nano-TiO₂ are suspected to influence the bioavailability and toxicity of co-existing organic or inorganic pollutants differently in aquatic environment. Recently, bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), a novel brominated flame retardants (NBFRs) with potential lipid-metabolism disruptive effects, has been detected prevalently in multiple environments including where nano-TiO₂ was also observed. However, their interaction in aqueous phase and modification of nano-TiO₂ on biological processes and toxicity of TBPH at environmental relevant levels remain unknown. Accordingly, we exposed zebrafish embryos to TBPH (1, 10, 100 and 1000 μg/L) alone or with nano-TiO₂ (100 μg/L) until 72 h post-fertilization (hpf) with emphasis on their physicochemical interactions in solutions and variations of bioavailability and toxicity regarding lipid metabolism in vivo. Zeta potential, fourier transform infrared (FTIR) spectroscopy and TEM-EDS revealed adsorption and agglomeration between TBPH and nano-TiO₂in vitro. Decreased body contents of nano-TiO₂ and TBPH implied a reduction of TBPH in bioavailability. The enhanced lipid metabolism and reduced fat storage by TBPH alone were all alleviated by co-exposure to nano-TiO₂. The overall results indicate that nano-TiO₂ adsorbed TBPH to form size-enlarged agglomerates and led to decreased bioavailability and consequently mitigated lipid metabolism disorders in developing zebrafish embryo/larvae.

Altering natural photosynthesis through quantum dots: effect of quantum dots on viability, light harvesting capacity and growth of photosynthetic organisms

Quantum dots are versatile fluorescent semiconductor nanocrystals with unique photophysical properties. They have been used in various research fields of biotechnology effectively for almost three decades including cell imaging, protein tracking, energy transfer, etc. With their great potential as energy donors or acceptors, quantum dots have also been used in many studies about altering growth rate and photosynthetic activity of photosynthetic organisms by manipulating their light harvesting capacity. In this review, effect of quantum dots on growth rate of photosynthetic organisms and light harvesting capacity of photosynthetic organisms were discussed in details together with toxic effects of cadmium-based and carbon-based quantum dots on photosynthetic organisms. In short, as one of the promising materials of nanotechnology, quantum dots have become one of the essential research topics in photosynthesis research area and will help researchers to manipulate natural photosynthesis in future.

Alleviation role of functional carbon nanodots for tomato growth and soil environment under drought stress

The biotoxicity and environmental applications of carbon nanomaterials have always been the focus of research. In this research, functional carbon nanodots (FCNs) show high promotion effects on regulating the growth, development and yield of tomato under drought stress, due to their up-regulation effects on the physiological processes of plants including photosynthesis, antioxidant system, osmotic adjustment, as well as soil amelioration in physicochemical properties and microbial environment during vegetative and reproductive growth stage. The reduction of tissue water content and water use efficiency are moderated by FCNs through improving root vigor and osmolytes (soluble sugar and proline) level, which contributes to maintain the enzyme function, photosynthesis and nutrient uptake in plant. FCNs regulate the enzymatic and non-enzymatic antioxidant system to scavenge reactive oxygen species (ROS) and inhibit the lipid peroxidation, thus protect the membrane structure and function of plant cells under stress. FCNs up-regulate soil microbial communities under drought stress by regulating the soil pH, enzyme activity, organic carbon and organic matters contents. Our results prove that FCNs are biological friendly to plant growth and soil environment under drought stress, thus exhibit potential as emendator to promote plant tolerance and improve agricultural productivity in water-deficient areas.

Effects of functional carbon nanodots on water hyacinth response to Cd/Pb stress: Implication for phytoremediation

Phytoremediation is one of the effective, economic and green approaches to cope with the increasing worldwide heavy metal (HM) pollution. Here, we evaluate the effects of functional carbon nanodots (FCNs) against the hyperaccumulation capacity as well as the physiological and genetic responses of water hyacinth under Pb²⁺ or/and Cd²⁺ stress. The bioaccumulation efficiency, HM content and transfer factor, biomass, root development, chlorophyll content, antioxidant system and genes expression are investigated at various concentration of HMs. Based on the excellent adsorption capacity and plant growth regulation ability, FCNs and nitrogen doped FCNs (N-FCNs) cooperate with water hyacinth to improve their HMs removal efficiencies. FCNs and N-FCNs immobilize excess HMs ions in plant, smartly regulate enzymatic levels to mitigate oxidative damage, as well as regulate the microelement uptake and related gene expression, thus improve plant tolerance against HMs stress. Although Pb and Cd have antagonistic effects on bioaccumulation of water hyacinth to the single metal, FCNs and N-FCNs can cooperate with water hyacinth to raise the removal efficiency of HMs in water, and enhance plant tolerance under Pb-Cd combined stress. The promotion effects of FCNs and N-FCNs on phytoremediation are more effective than conventional carbon nanomaterials, including carbon nanotubes and graphene oxides. These findings demonstrate that the application of FCNs or N-FCNs can improve the phytoremediation efficiency in the restoration of HMs contaminated water area. This study provides important insights into the possibility of using FCNs-based nanomaterials and water hyacinth as synergistic system for remediation of Cd-Pb contaminated water area.

Dual Effect of Nanomaterials on Germination and Seedling Growth: Stimulation vs. Phytotoxicity

Due to recent active research, a large amount of data has been accumulated regarding the effects of different nanomaterials (mainly metal oxide nanoparticles, carbon nanotubes, chitosan nanoparticles) on different plant species. Most studies have focused on seed germination and early seedling development, presumably due to the simplicity of these experimental systems. Depending mostly on size and concentration, nanomaterials can exert both positive and negative effects on germination and seedling development during normal and stress conditions, thus some research has evaluated the phytotoxic effects of nanomaterials and the physiological and molecular processes behind them, while other works have highlighted the favorable seed priming effects. This review aims to systematize and discuss research data regarding the effect of nanomaterials on germination and seedling growth in order to provide state-of-the-art knowledge about this fast developing research area.