The presence of carbon nanostructures in bakery products induces metabolic stress in human mesenchymal stem cells through CYP1A and p53 gene expression

Edible coating using carbon quantum dots for fresh produce preservation: A review of safety perspectives

Fresh produce deteriorates and spoils after harvest due to its perishable nature. Deterioration in quality over time has become a major problem for the food industry, placing an undue burden on the economy and agriculture. Food scientists have developed various methods and technologies to prevent spoilage of fruits and vegetables during storage and logistics. Utilizing carbon quantum dots (CQDs) in the form of active packaging and coatings has been a popular strategy recently. CQDs have recently attracted attention as sustainable and functional nanomaterials. CQDs are popular among food scientists due to their easy and economical synthesis, sustainability, non-toxicity, biocompatibility, edibility, UV protection, and antibacterial and antioxidant activities. Although many studies have been conducted and reviewed on the utilization of CQDs in the manufacture of flexible active packaging materials, relatively few studies have investigated the use of CQDs in edible coating formulations for fresh produce. The main reasons for this are concerns about the potential toxicity and edibility of CQDs if they are coated directly on fresh produce. Therefore, this review aims to address these issues by investigating the dose-dependent non-toxicity and biocompatibility of sustainable CQDs along with other important properties from a food packaging perspective. Additionally, this review focuses on the studies performed so far on the direct coating of CQD-based formulations on fresh and fresh-cut fruits and vegetables and discusses the important impact of CQDs on the quality of coated agricultural products. This review is intended to provide food packaging researchers with confidence and prospects for utilizing sustainable CQDs in direct coating formulations for food.

Foodborne Carbon Dots Aggravate High-Fat-Diet-Induced Glucose Homeostasis Imbalance by Disrupting the Gut-Liver Axis

Foodborne carbon dots (CDs) are generally produced during cooking and exist in food items. Generally, CDs are regarded as nontoxic materials, but several studies have gradually confirmed the cytotoxicity of CDs, such as oxidative stress, reduced cellular activity, apoptosis, etc. However, studies focusing on the health effects of long-term intake of food-borne CDs are scarce, especially in populations susceptible to metabolic disease. In this study, we reported that CDs in self-brewing beer had no effect on glucose metabolism in CHOW-fed mice but exacerbated high-fat-diet (HFD)-induced glucose metabolism disorders via the gut-liver axis. Chronic exposure to foodborne CDs increased fasting glucose levels and exacerbated liver and intestinal barrier damage in HFD-fed mice. The 16s rRNA sequencing analysis revealed that CDs significantly altered the gut microbiota composition and promoted lipopolysaccharide (LPS) synthesis-related KEGG pathways (superpathway of (Kdo)2-lipid A, Kdo transfer to lipid IVA Ill (Chlamydia), lipid IVA biosynthesis, and so on) in HFD-fed mice. Mechanically, CD exposure increased the abundance of Gram-negative bacteria (Proteobacteria and Desulfovibrionaceae), thus producing excessive endotoxin-LPS, and then LPS was transferred by the blood circulation to the liver due to the damaged intestinal barrier. In the liver, LPS promoted TLR4/NF-κB/P38 MAPK signaling, thus enhancing systemic inflammation and exacerbating HFD-induced insulin resistance. However, pretreating mice with antibiotics eliminated these effects, indicating a key role for gut microbiota in CDs exacerbating glucose metabolism disorders in HFD-fed mice. The finding herein provides new insight into the potential health risk of foodborne nanoparticles in susceptible populations by disturbing the gut-liver axis.

Understanding the Interaction between Nanomaterials Originated from High-Temperature Processed Starch/Myristic Acid and Human Monocyte Cells

High-temperature cooking approaches trigger many metabolically undesirable molecule formations, which pose health risks. As a result, nanomaterial formation has been observed while cooking and reported recently. At high temperatures, starch and myristic acid interact and lead to the creation of nanomaterials (cMS-NMs). We used a non-polar solvent chloroform to separate the nanomaterials using a liquid-liquid extraction technique. The physico-chemical characterization was carried out using dynamic light scattering (DLS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR). To determine the biological impact of these nanomaterials using different in vitro assays, including a cell viability assay, microscopic staining, and gene expression analysis, we adopted the THP-1 cell line as an in vitro monocyte model in our study. The TEM images revealed that fabricated cMS nanomaterials are smaller than 100 nm in diameter. There were significant concerns found in the cytotoxicity assay and gene expression analysis. At concentrations of 100-250 µg/mL, the cMS-NMs caused up to 95% cell death. We found both necrosis and apoptosis in cMS-NMs treated THP-1 cells. In cMS-NMs-treated THP-1 cells, we found decreased expression levels in IL1B and NFKB1A genes and significant upregulation in MIF genes, suggesting a negative immune response. These findings strongly suggest that cMS-NMs originated from high-temperature food processing can cause adverse effects on biological systems. Therefore, charred materials in processed foods should be avoided in order to minimize the risk of health complications.

Fabrication of myristic acid-potato starch complex nanostructures and assessment of their cytotoxic behavior

BACKGROUND

Lipids and carbohydrates perform essential functions in foods. In recent decades, food scientists have studied the effects of carbohydrate-lipid interactions on the functional properties of food. However, the ways in which carbohydrate-lipid complex-derived materials affect the biological system are unknown. In this study, a myristic acid-potato starch complex was created using a simple cooking approach. The complex was employed as a precursor for the fabrication of myristic acid-potato starch complex-based nanostructured materials (MPS-NMs) through a liquid-liquid extraction approach. A study was conducted on the structural and cytotoxic features of the fabricated MPS-NMs.

RESULTS

Transmission electron microscopy images confirmed the formation of spherical nanostructures, 3-60 nm in size. After 24 h exposure, the chloroform fraction-based and n-hexane fraction-based MPS-NMs increased cell death by ~90% and ~ 82%, respectively. Chloroform fraction-based MPS-NMs (CMPS-NMs) triggers apoptotic cell death in human mesenchymal stem cells (hMSCs). n-Hexane fraction-based MPS-NMs (HMPS-NMs) treated cells have red color-intact nuclei, attributed to necrotic cell death. The CMPS-NMs and HMPS-NMs significantly decreased the mitochondria membrane potential and increased the intracellular reactive oxygen species (ROS) levels. We observed significant downregulation in flavin-containing monooxygenase (FMO), Ataxia Telangiectasia Mutated (ATM), and uridine diphosphate glucuronosyltransferases (UGT) gene expression levels in the exposed cells of CMPS-NMs and HMPS- NMs. In addition, we found upregulation of glutathione-disulfide reductase (GSR) and glutathione S-transferase A4 (GSTA4) genes in CMPS-NMs, and HMPS-NMs exposure.

CONCLUSION

The cooking process may lead to the formation of nanostructured material in food systems. Chloroform fraction-based MPS-NMs and HMPS-NMs may contribute to cell metabolic disorders. © 2023 Society of Chemical Industry.

An Overview of the Potential of Food-Based Carbon Dots for Biomedical Applications

Food-based carbon dots (CDs) hold significant importance across various fields, ranging from biomedical applications to environmental and food industries. These CDs offer unique advantages over traditional carbon nanomaterials, including affordability, biodegradability, ease of operation, and multiple bioactivities. This work aims to provide a comprehensive overview of recent developments in food-based CDs, focusing on their characteristics, properties, therapeutic applications in biomedicine, and safety assessment methods. The review highlights the potential of food-based CDs in biomedical applications, including antibacterial, antifungal, antivirus, anticancer, and anti-immune hyperactivity. Furthermore, current strategies employed for evaluating the safety of food-based CDs have also been reported. In conclusion, this review offers valuable insights into their potential across diverse sectors and underscores the significance of safety assessment measures to facilitate their continued advancement and application.

Recent developments, applications and challenges for carbon quantum dots as a photosynthesis enhancer in agriculture

Since the world's population is expanding, mankind may be faced with a huge dilemma in the future, which is food scarcity. The situation can be mitigated by employing sustainable cutting-edge agricultural methods to maintain the food supply chain. In recent years, carbon quantum dots (CQD), a member of the well-known carbon-based nanomaterials family, have given rise to a new generation of technologies that have the potential to revolutionise horticulture and agriculture research. CQD has drawn much attention from the research community in agriculture owing to their remarkable properties such as good photoluminescence behaviour, high biocompatibility, photo-induced electron transfer, low cost, and low toxicity. These unique properties have led CQD to become a promising material to increase plant growth and yield in the agriculture field. This review paper highlights the recent advances of CQD application in plant growth and photosynthesis rate at different concentrations, with a focus on CQD uptake and translocation, as well as electron transfer mechanism. The toxicity and biocompatibility studies of CQD, as well as industrial scale applications of CQD for agriculture are discussed. Finally, the current challenges of the present and future perspectives in this agriculture research are presented.

Malting barley carbon dots-mediated oxidative stress promotes insulin resistance in mice via NF-κB pathway and MAPK cascade

Background

Food-borne carbon dots (CDs) are widely generated during food processing and are inevitably ingested by humans causing toxicity. However, the toxic effects of food-borne CDs on the blood glucose metabolism are unknown.

Results

In this study, we brewed beer via a representative strategy and extracted the melting-barley CDs (MBCDs) to explore the toxic effects on blood glucose in mice. We found the accumulation of fluorescent labeled MBCDs in various organs and oral administration of MBCDs can cause visceral toxicity, manifested as liver damage. Mice were orally administered MBCDs (5 and 25 mg/kg) for 16 weeks, and increased levels of fasting blood glucose were observed in both MBCDs-treated groups. Transcriptomic analyses revealed that MBCDs activate oxidative stress, inflammatory responses, the MAPK cascade, and PI3K/Akt signaling in mice livers. Mechanistically, MBCDs exposure-induced reactive oxygen species (ROS) overproduction activates the nuclear factor-κB (NF-κB) signaling pathway and MAPK cascade, thereby promoting phosphorylated insulin receptor substrate (IRS)-1 at Ser307 and inducing insulin resistance (IR). Meanwhile, the IR promoted gluconeogenesis, which enhanced MBCDs-induced hyperglycemia of mice. Importantly, inhibition of the ROS significantly attenuated the MBCDs-induced inflammatory response and MAPK cascade, thereby alleviating IR and hyperglycemia in mice.

Conclusion

In summary, this study revealed that MBCDs promote ROS overproduction and thus induced IR, resulting in imbalance of glucose homeostasis in mice. More importantly, this study was further assessed to reveal an imperative emphasis on the reevaluation of dietary and environmental CDs exposure, and has important implications for T2DM prevention research.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01543-1.

Advantages and prospects of stem cells in nanotoxicology

Nanomaterials have been widely used in many fields, especially in biomedical and stem cell therapy. However, the potential risks associated with nanomaterials applications are also gradually increasing. Therefore, effective and robust toxicology models are critical to evaluate the developmental toxicity of nanomaterials. The development of stem cell research provides a new idea of developmental toxicology. Recently, many researchers actively investigated the effects of nanomaterials with different sizes and surface modifications on various stem cells (such as embryonic stem cells (ESCs), adult stem cells, etc.) to study the toxic effects and toxic mechanisms. In this review, we summarized the effects of nanomaterials on the proliferation and differentiation of ESCs, mesenchymal stem cells and neural stem cells. Moreover, we discussed the advantages of stem cells in nanotoxicology compared with other cell lines. Finally, combined with the latest research methods and new molecular mechanisms, we analyzed the application of stem cells in nanotoxicology.

Assessment of Potential Toxicity of Onion-like Carbon Nanoparticles from Grilled Turbot Scophthalmus maximus L

Although the presence of foodborne nanoparticles was confirmed in grilled fish in a previous study, the evaluation of potential health risks of these NPs was insufficient. In the present study, the potential toxicity of onion-like carbon nanoparticles (OCNPs) separated from grilled turbot Scophthalmus maximus L. was evaluated using mouse osteoblasts cells model and zebrafish (Danio rerio) model. Cytotoxicity evaluation revealed that the OCNPs penetrated into the MC3T3-E1 cells without arousing cell morphology changes. No evident apoptosis or damage of cells was observed with increasing OCNPs’ concentration to 20 mg/mL. In the hemolysis test, OCNPs did not show an obvious hemolysis effect on red blood cells. In the acute toxicity test, the LC₅₀ value (212.431 mg/L) of OCNPs to zebrafish showed a weak acute toxicity. In subacute toxicity test, after exposure to OCNPs (30 mg/L, 40 mg/L) for 10 days, a significant increase of reactive oxygen species level of zebrafish was observed. Meanwhile, redundant ROS content caused inhibition to several antioxidant enzymes and induced lipid and protein peroxidation damages according to the upregulation of malondialdehyde and protein carbonyl levels. The chronic toxicity test results indicated that oxidative stress was only observed in the high concentration group of OCNPs-treated zebrafish.

Effects of adding sodium nitrite and tea polyphenols on the characterizations and cytotoxicity of carbon nanoparticles from fried pork

Carbon nanoparticles (CNPs) extensively present in thermal-processed foods. Sodium nitrite (NaNO₂) and tea polyphenols (TP) are commonly used in meat processing, while the properties and cytotoxicity of CNPs existed in fried pork added NaNO₂ and TP remain unknown. The results showed that compared with no addition (NA, 4.008 ± 0.43 nm) in soaked pork, the smaller diameters of CNPs (0.968 ± 0.44 nm) were found in CNPs-NaNO₂-20 group (addition 20 mg/kg NaNO₂), the larger (155.8 ± 7.30 nm) in CNPs-TP-100 group (addition 100 mg/kg TP). The diameter of CNPs was positively correlated with the added concentration. CNPs decreased the viability of HL-7702 cells. Compared with NA group, cell viability in CNPs-NaNO₂-80 group was obviously (p < 0.05) decreased by 3.17%, while the CNPs-TP-200 group was 13.84% higher. CNPs could block cells growth by arresting cells in S-phase and increasing cellular ROS levels. CNPs generated in fired pork added 200 mg/kg TP in soaking showed less cytotoxicity.

The effects of carbon dots produced by the Maillard reaction on the HepG2 cell substance and energy metabolism

Endogenous nanoparticles produced during food processing have received considerable attention due to their unique physicochemical properties and potential safety risks. However, the bio-impact of endogenous nanoparticles on cell metabolism has not been fully studied. In this work, the effects of carbon dots (CDs) derived from the Maillard reaction of glucose and lysine on the cellular substance and energy metabolism were assessed using HepG2 cells as a model. When the HepG2 cells were incubated with 10.0 mg mL-1 of CDs, the mitochondrial membrane potential decreased significantly and the mitochondrial function was affected. The extracellular acidification rate and oxygen consumption rate were decreased in comparison to normal cells without CDs. The CDs blocked the glycolysis pathway by reducing the activities of key enzymes including phosphofructokinase and pyruvate kinase. The energy supply pathway of HepG2 cells changed from glycolysis to TCA cycle, but the increase of the TCA cycle flux could not meet the requirements for restoring cell proliferation. The increase of the compensatory flux in the TCA cycle may be the result of up-regulation of the metabolism of glucogenic amino acids and ketogenic amino acids, while lipid metabolism did not seem to be affected in this process.

Simultaneous fabrication of carbon nanodots and hydroxyapatite nanoparticles from fish scale for biomedical applications

Fish industries and markets produce large quantities of fish scales, skins, shells, and bone wastes post processing that contaminate the environment and cause health risks in humans. In this context, we have developed a novel and simple integrated process to valorize the Lethrinus lentjan fish scales by fabricate carbon nanodots (CDs) and hydroxyapatite nanoparticles (HA NPs) simultaneously. The fish scale treatment was carried out by hydrothermal method at 280 °C that produced CDs and HA NPs simultaneously. Under hydrothermal treatment, organic and inorganic substances of fish scale is transformed to CDs and HA NPs respectively. As TEM images confirmed that fish scale derived CDs were spherically shaped and ~3 to 15 nm in size. The CDs exhibited excitation-dependent emission in photoluminescence. The HA NPs were ~8 to 12 nm in diameter and ~50 to 100 nm in length with rod shape. Also, HA NPs possess spherical shape nanostructures with 15-50 nm in diameter. Furthermore, we assessed the cytotoxic behavior of synthesized nanostructures using the MTT assay and acridine orange/ethidium bromide (AO/EB) staining. These results showed that synthesized CDs and HA NPs did not cause significant changes in cell viability and morphology, indicating biocompatibility. Additionally, the synthesized CDs and HA NPs were exploited as fluorescent probes for cellular imaging and osteogenic differentiation of stem cells respectively. Overall, the study results indicate that low-cost fish waste was valorized by producing CDs and HA NPs concurrently. The synthesized nanostructures can be applicable for bio-imaging and bone tissue engineering applications.

Endogenous Fluorescence Carbon Dots Derived from Food Items

Background

Fluorescent carbon dots (CDs) are a novel class of carbon-based nanomaterials that were discovered in 2004. However, nobody knew that CDs existed in food items naturally until 2012. Properties of nanosize materials are distinct from those of their bulk materials due to the particle size and accordingly alter their bioavailability and/or biocompatibility. Therefore, the potential health risk of nanoparticles in food has drawn massive attention. Currently, almost all studies regarding the biosafety of nanoparticles in food have mainly focused on engineered nanoparticles used as food additives and have excluded the endogenous nanoparticles in food. Therefore, investigation of the properties of food-borne fluorescent CDs and their potential health risk to humans is of great significance.

Scope and approach

This review summarizes the existing literature on fluorescent carbon dots (CDs) in food, with particular attention to their properties, formation process, and the potential health risks posed to consumers. The knowledge gap between food-borne nanoparticles and their potential risks is identified, and future research is proposed.

Key findings and conclusions

The presence of fluorescent CDs in food produced during food processing has been summarized. Fluorescent CDs less than 10 nm in size mainly contain carbon, oxygen, hydrogen, and/or nitrogen. The presence of CDs in food items was first demonstrated in 2012, and their formation was attributed to heating of the starting material. The properties of CDs in food are different from the engineered nanoparticles used as food as additives and represent a novel kind of nanostructure in food. Further studies should focus on the chronic effects of CDs, although their toxicity is low, because investigations both in vivo and in vitro are limited.

Adverse effects of fluorescent carbon dots from canned yellow croaker on cellular respiration and glycolysis

Adverse effects on cellular respiration and glycolysis were investigated for the fluorescent carbon dots from canned yellow croaker.

Carbon black suppresses the osteogenesis of mesenchymal stem cells: the role of mitochondria

BACKGROUND

The rapid increase in carbon black poses threats to human health. We evaluated the effect of CB (Printex 90) on the osteogenesis of bone-marrow-derived mesenchymal stem cells (MSCs). Mitochondria play an important role in the osteogenesis of MSCs and are potential targets of nanomaterials, so we studied the role of mitochondria in the CB Printex 90-induced effects on osteogenesis.

RESULTS

Low doses of Printex 90 (3 ng/mL and 30 ng/mL) that did not cause deleterious effects on MSCs' viability significantly inhibited osteogenesis of MSCs. Printex 90 caused down-regulation of osteoblastic markers, reduced activity of alkaline phosphatase (ALP), and poor mineralization of osteogenically induced MSCs. Cellular ATP production was decreased, mitochondrial respiration was impaired with reduced expression of ATPase, and the mitochondrial membrane was depolarized. The quantity and quality of mitochondria are tightly controlled by mitochondrial biogenesis, mitochondrial dynamics and mitophagy. The transcriptional co-activator and transcription factors for mitochondrial biogenesis, PGC-1α, Nrf1 and TFAM, were suppressed by Printex 90 treatment, suggesting that decreased biogenesis was caused by Printex 90 treatment during osteogenesis. Mitochondrial fusion and fission were significantly inhibited by Printex 90 treatment. PINK1 accumulated in Printex 90-treated cells, and more Parkin was recruited to mitochondria, indicating that mitophagy increased to remove the damaged mitochondria.

CONCLUSIONS

This is the first report of the inhibitory effects of CB on the osteogenesis of MSCs and the involvement of mitochondria in CB Printex 90-induced suppression of MSC osteogenesis.

Presence and Formation Mechanism of Foodborne Carbonaceous Nanostructures from Roasted Pike Eel ( Muraenesox cinereus)

Foodborne nanostructures have gained more and more attention in recent years. In this paper, the presence and physicochemical properties of carbonaceous nanostructures (CNSs) from roasted pike eel ( Muraenesox cinereus) were reported. The monodispersed CNSs are strongly photoluminescent under the illustration of ultraviolet (UV) light, with a fluorescent quantum yield of 80.16%, and display excitation-dependent emission behavior. The formation of CNSs is believed to go through a process of morphology evolution, including polymerization, pyrolysis, nucleation, growth, emergence, and blossom. The optical properties of the CNSs were shown to be affected by the roasting temperature. Furthermore, cellular uptake of the CNSs was investigated, and it is shown that the CNSs were clearly absorbed into live cells and were mainly distributed within the cell cytoplasm and not in the cell nucleus. This work is among the very first reports on CNSs present in roasted fish, providing valuable insights into the formation mechanism of such nanostructures and showcasing the biodistribution of these food-originated CNSs in live cells.

Fluorescent Carbon Dots Derived from Maillard Reaction Products: Their Properties, Biodistribution, Cytotoxicity, and Antioxidant Activity

Food-borne nanoparticles have received great attention because of their unique physicochemical properties and potential health risk. In this study, carbon dots (CDs) formed during one of the most important chemical reactions in the food processing field, the Maillard reaction from the model system including glucose and lysine, were investigated. The CDs purified from Maillard reaction products emitted a strong blue fluorescence under ultraviolet light with a fluorescent quantum yield of 16.30%. In addition, they were roughly spherical, with sizes of around 4.3 nm, and mainly composed of carbon, oxygen, hydrogen, and nitrogen. Their surface groups such as hydroxyl, amino, and carboxyl groups were found to possibly enable CDs to scavenge DPPH and hydroxyl radicals. Furthermore, the cytotoxicity assessment of CDs showed that they could readily enter HepG2 cells while causing negligible cell death at low concentration. However, high CDs concentrations were highly cytotoxic and led to cell death via interference of the glycolytic pathway.

Presence of Fluorescent Carbon Nanoparticles in Baked Lamb: Their Properties and Potential Application for Sensors

The presence of nanoparticles in food has drawn much attention in recent years. Fluorescent carbon nanoparticles are a new class of nanostructures; however, the distribution and physicochemical properties of such nanoparticles in food remain unclear. Herein, the presence of fluorescent carbon nanoparticles in baked lamb was confirmed, and their physicochemical properties were investigated. The fluorescent carbon nanoparticles from baked lamb emit strong blue fluorescence under ultraviolet light with a 10% fluorescent quantum yield. The nanoparticles are roughly spherical in appearance with a diameter of around 2.0 nm. Hydroxyl, amino, and carboxyl groups exist on the surface of nanoparticles. In addition, the nanoparticles could serve as a fluorescence sensor for glucose detection through an oxidation-reduction reaction. This work is the first report on fluorescent carbon nanoparticles present in baked lamb, which provides valuable insight into the physicochemical properties of such nanoparticles and their potential application in sensors.

A fluorescence turn-off-on chemosensor based on carbon nanocages for detection of ascorbic acid

A type of carbon nanocages has been constructed through grilling of turbot by a facile method, and applied successfully as a fluorescent probe for rapid, selective as well as sensitive detection of ascorbic acid.

Physicochemical properties and cytotoxicity of carbon dots in grilled fish

Fluorescent CDs with good biocompatibility and low cytotoxicity are extracted from grilled pike eel, which are used for bio-imaging.