Toxicity Alleviation of Carbon Dots from Roast Beef after the Formation of Protein Coronas with Human Serum Albumin

Maillard Reaction-Derived S-Doped Carbon Dots Promotes Downregulation of PPARγ, C/EBPα, and SREBP-1 Genes In-Vitro

Carbon nanodots (CDs) are commonly found in food products and have attracted significant attention from food scientists. There is a high probability of CD exposure in humans, but its impacts on health are unclear. Therefore, health effects associated with CD consumption should be investigated. In this study, we attempted to create a model system of the Maillard reaction between cystine and glucose using a simple cooking approach. The CDs (CG-CDs) were isolated from cystine-glucose-based Maillard reaction products and characterized using fluorescence spectroscopy, X-ray diffractometer (XRD), and transmission electron microscope (TEM). Furthermore, human mesenchymal stem cells (hMCs) were used as a model to unravel the CDs' cytotoxic properties. The physiochemical assessment revealed that CG-CDs emit excitation-dependent fluorescence and possess a circular shape with sizes ranging from 2 to 13 nm. CG-CDs are predominantly composed of carbon, oxygen, and sulfur. The results of the cytotoxicity evaluation indicate good biocompatibility, where no severe toxicity was observed in hMCs up to 400 μg/mL. The DPPH assay demonstrated that CDs exert potent antioxidant abilities. The qPCR analysis revealed that CDs promote the downregulation of the key regulatory genes, PPARγ, C/EBPα, SREBP-1, and HMGCR, coupled with the upregulation of anti-inflammatory genes. Our findings suggested that, along with their excellent biocompatibility, CG-CDs may offer positive health outcomes by modulating critical genes involved in lipogenesis, homeostasis, and obesity pathogenesis.

Size-controllable food-grade nanoparticles based on sea cucumber polypeptide with good anti-oxidative capacity to prolong lifespan in tumor-bearing mice

Liver cancer, a malignancy with a rising global incidence, poses a significant challenge in achieving effective treatment outcomes. As food-derived nutrient, sea cucumber peptide (SCP) has shown promising anticancer effects. Therefore, we explored the nanodelivery systems to encapsulate SCP to enhance its stability in the gastrointestinal tract and improve absorption within the tumor microenvironment. This study aimed to develop size-controllable multifunctional nanoparticles using SCP, procyanidins (PCs), and vanillin through molecular assembly via a one-pot Mannich condensation approach. These food-grade nanoparticles demonstrated water solubility and exhibited a spherical structure with sizes ranging from 441 to 1360 nm, depending on the concentration of the reactants. In vitro cell experiments demonstrated that SCP nanoparticles modified with PCs effectively reduced the generation of reactive oxygen species from H2O2 and acrylamide while maintaining normal levels of mitochondrial membrane potential. Furthermore, in vivo nutrition intervention studies conducted on tumor-bearing mice revealed that mice treated with SCP nanoparticles exhibited a survival rate of 40 %, which was significantly higher than the 0 % and 20 % survival rates observed in the control and SCP-treated groups, respectively. These findings suggest that SCP nanoparticles, possessing antioxidative properties and controllable sizes, hold potential for precision nutrition in the field of cancer treatment.

Effects of different roasting temperatures on rabbit meat protein oxidation and fluorescent carbon nanoparticle formation

This study explores the oxidation of rabbit meat proteins and the physicochemical properties of the resulting fluorescent carbon nanoparticles (CNPs) under various roasting temperatures (180, 210, 240, 270, and 300 °C). The determination of sulfhydryl content, along with the results from UV and fluorescence spectroscopy, indicates that the protein structure undergoes changes during the roasting process, and the degree of oxidation shows an increasing trend with rising roasting temperatures. The CNP solution obtained exhibits a typical blue fluorescence. Moreover, as the roasting temperature increases from 180 °C to 300 °C, the relative content of the three elements in CNPs, namely C, N, and O, increases by 12 %, -3%, and -9 %, respectively. The surface of the obtained rabbit meat CNPs contains hydrophilic and polycyclic groups, such as carbonyl, hydroxyl, and amide bonds. Correlation analysis reveals a significant positive correlation between the degree of protein oxidation and the fluorescence intensities of CNPs.

An overview on animal/human biomass-derived carbon dots for optical sensing and bioimaging applications

Over the past decade, carbon dots (CDs) have emerged as some of the extremely popular carbon nanostructures for diverse applications. The advantages of sustainable CDs, characterized by their exceptional photoluminescence (PL), high water solubility/dispersibility, non-toxicity, and biocompatibility, substantiate their potential for a wide range of applications in sensing and biology. Moreover, nature offers plant- and animal-derived precursors for the sustainable synthesis of CDs and their doped variants. These sources are not only readily accessible, inexpensive, and renewable but are also environmentally benign green biomass. This review article presents in detail the production of sustainable CDs from various animal and human biomass through bottom-up synthetic methods, including hydrothermal, microwave, microwave-hydrothermal, and pyrolysis methods. The resulting CDs exhibit a uniform size distribution, possibility of heteroatom doping, surface passivation, and remarkable excitation wavelength-dependent/independent emission and up-conversion PL characteristics. Consequently, these CDs have been successfully utilized in multiple applications, such as bioimaging and the detection of various analytes, including heavy metal ions. Finally, a comprehensive assessment is presented, highlighting the prospects and challenges associated with animal/human biomass-derived CDs for multifaceted applications.

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.

The interplay between lysosome, protein corona and biological effects of cationic carbon dots: Role of surface charge titratability

Carbon dots (CDs) are nanoparticles (NPs) with potential applications in the biomedical field. When in contact with biological fluids, most NPs are covered by a protein corona. As well, upon cell entry, most NP are sequestered in the lysosome. However, the interplay between the lysosome, the protein corona and the biological effects of NPs is still poorly understood. In this context, we investigated the role of the lysosome in the toxicological responses evoked by four cationic CDs exhibiting protonatable or non-protonatable amine groups at their surface, and the associated changes in the CD protein corona. The four CDs accumulated in the lysosome and led to lysosomal swelling, loss lysosome integrity, cathepsin B activation, NLRP3 inflammasome activation, and cell death by pyroptosis in a human macrophage model, but with a stronger effect for CDs with titratable amino groups. The protein corona formed around CDs in contact with serum partially dissociated under lysosomal conditions with subsequent protein rearrangement, as assessed by quantitative proteomic analysis. The residual protein corona still contained binding proteins, catalytic proteins, and proteins involved in the proteasome, glycolysis, or PI3k-Akt KEGG pathways, but with again a more pronounced effect for CDs with titratable amino groups. These results demonstrate an interplay between lysosome, protein corona and biological effects of cationic NPs in link with the titratability of NP surface charges.

Nanoparticle platform comprising lipid-tailed pH-sensitive carbon dots with minimal drug loss

Herein, we synthesized a lipid-mimicking organic material (PCD_FA) that can surpass the efficacy of lipid-based nanoparticles and demonstrated its potential as a delivery vehicle for various hydrophilic drugs. PCD_FA is a conjugate of pH-sensitive carbon dots (PCDs) and fatty acids (FAs) and has potential applications in several fields owing to various combinations of carbon dots (CDs) and FAs. Similar to phospholipids, PCD-FAs have hydrophilic heads and hydrophobic tails that allow them to self-form nanoparticles (Coposomes) in the aqueous phase. Coposomes can easily combine various hydrophilic head and hydrophobic tail combinations, and several drugs can be encapsulated, or drug release patterns can be controlled according to each property. We analyzed the differences in size, drug loading efficiency, and drug release patterns of Coposomes depending on the type of FAs and characteristics of the encapsulated drugs. Additionally, cell entry and intracellular drug release mechanisms of the Coposomes were identified. The applicability of Coposomes as drug delivery carriers for tumor treatment has been demonstrated in comparison with that of liposomes formulation in tumor-bearing mouse models. Consequently, this study presents possibilities for the synthesis and application of various amphiphilic lipid-mimicking organic materials via the combination of CDs and FAs with various functions.

Carbon Quantum Dots from Roasted Coffee Beans: Their Degree and Mechanism of Cytotoxicity and Their Rapid Removal Using a Pulsed Electric Field

Carbon quantum dots (CQDs) from heat-treated foods show toxicity, but the mechanisms of toxicity and removal of CQDs have not been elucidated. In this study, CQDs were purified from roasted coffee beans through a process of concentration, dialysis and lyophilization. The physical properties of CQDs, the degree and mechanism of toxicity and the removal method were studied. Our results showed that the size of CQDs roasted for 5 min, 10 min and 20 min were about 5.69 ± 1.10 nm, 2.44 ± 1.08 nm and 1.58 ± 0.48 nm, respectively. The rate of apoptosis increased with increasing roasting time and concentration of CQDs. The longer the roasting time of coffee beans, the greater the toxicity of CQDs. However, the caspase inhibitor Z-VAD-FMK was not able to inhibit CQDs-induced apoptosis. Moreover, CQDs affected the pH value of lysosomes, causing the accumulation of RIPK1 and RIPK3 in lysosomes. Treatment of coffee beans with a pulsed electric field (PEF) significantly reduced the yield of CQDs. This indicates that CQDs induced lysosomal-dependent cell death and increased the rate of cell death through necroptosis. PEF is an effective way to remove CQDs from roasted coffee beans.

Emerging Nanoparticles in Food: Sources, Application, and Safety

Nanoparticles (NPs) are small-sized, with high surface activity and antibacterial and antioxidant properties. As a result, some NPs are used as functional ingredients in food additives, food packaging materials, nutrient delivery, nanopesticides, animal feeds, and fertilizers to improve the bioavailability, quality, and performance complement or upgrade. However, the widespread use of NPs in the industry increases the exposure risk of NPs to humans due to their migration from the environment to food. Nevertheless, some NPs, such as carbon dots, NPs found in various thermally processed foods, are also naturally produced from the food during food processing. Given their excellent ability to penetrate biopermeable barriers, the potential safety hazards of NPs on human health have attracted increased attention. Herein, three emerging NPs are introduced including carbon-based NPs (e.g., CNTs), nanoselenium NPs (SeNPs), and rare earth oxide NPs (e.g., CeO₂ NPs). In addition, their applications in the food industry, absorption pathways into the human body, and potential risk mechanisms are discussed. Challenges and prospects for the use of NPs in food are also proposed.

Association of dietary meat consumption habits with neurodegenerative cognitive impairment: an updated systematic review and dose-response meta-analysis of 24 prospective cohort studies

The association between dietary meat consumption habits and neurodegenerative cognitive impairment (NCI) has been made but recent studies have reported controversial results. Herein, we have systematically explored associations between meat consumption and NCI risk. PubMed, Embase, and MEDLINE databases were explored for data sources of primary studies. Twenty-four prospective cohort studies that met the selection criteria, involving over 500 000 participants from 11 countries, were included. Relative risks (RRs) were pooled using random-effects model meta-analysis, and a dose-response analysis was conducted using a 2-stage generalized least-squares trend program. The results showed that total meat (RRs 1.14; 95% CI: 1.04-1.24), fish (RRs 0.87; 95% CI: 0.78-0.98), and poultry (RRs 0.88; 95% CI: 0.80-0.98) intake was significantly associated with NCI risk but red meat (RRs 1.03; 95% CI: 0.92-1.16) showed a non-significant association. Subgroup analysis further demonstrated a significant association between total meat consumption and the risk of NCI, especially for total processed meat (RRs 1.67; 95% CI, 1.46-1.92) and processed red meat (RRs 1.22; 95% CI, 1.11-1.34). Each additional 50 g day^-1 intake of total meat (RRs 1.03; 95% CI: 1.00-1.05) and processed meat (RRs 1.12; 95% CI: 1.08-1.17) increased the risk of NCI. In contrast, a 50 g day^-1 increment of fish (RRs 0.97; 95% CI: 0.94-0.99) and poultry (RRs 0.948; 95% CI: 0.90-0.99) intake was associated with lower NCI risk. This study provided evidence for further understanding the relationship between the type and amount of meat intake and the occurrence of NCI.

Surface charge influences protein corona, cell uptake and biological effects of carbon dots

Carbon dots are emerging nanoparticles (NPs) with tremendous applications, especially in the biomedical field. Herein is reported the first quantitative proteomic analysis of the protein corona formed on CDs with different surface charge properties. Four CDs were synthesized from citric acid and various amine group-containing passivation reagents, resulting in cationic NPs with increasing zeta (ζ)-potential and density of positive charges. After CD contact with serum, we show that protein corona identity is influenced by CD surface charge properties, which in turn impacts CD uptake and viability loss in macrophages. In particular, CDs with high ζ-potential (>+30 mV) and charge density (>2 μmol mg^-1) are the most highly internalized, and their cell uptake is strongly correlated with a corona enriched in vitronectin, fibulin, fetuin, adiponectin and alpha-glycoprotein. On the contrary, CDs with a lower ζ-potential (+11 mV) and charge density (0.01 μmol mg^-1) are poorly internalized, while having a corona with a very different protein signature characterized by a high abundance of apolipoproteins (APOA1, APOB and APOC), albumin and hemoglobin. These data illustrate how corona characterization may contribute to a better understanding of CD cellular fate and biological effects, and provide useful information for the development of CDs for biomedical applications.

Change of Cell Toxicity of Food-Borne Nanoparticles after Forming Protein Coronas with Human Serum Albumin

Nanoparticles (NPs) can form protein coronas with plasma proteins after entering the biological environment due to their surface adsorption ability. In this study, the effects of protein coronas of roast squid food-borne nanoparticles (FNPs) with human serum albumin (HSA) on the HepG-2 and normal rat kidney (NRK) cells were investigated. The hydrodynamic diameters of the HSA and HSA-FNPs were 8 and 13 nm, respectively. The cytotoxicity and cell membrane damage of FNPs to HepG-2 cells increased with the increase of roasting temperature. The presence of 4.78 × 10^-3 mol/L FNPs increased the numbers of cellular necrosis and prolonged the G₂ phase of the cell cycle. The formation of protein coronas of squid FNPs mitigated the autophagy phenomenon by FNPs on HepG-2 cells. Moreover, protein coronas reduced the mitochondrial membrane potential in the HepG-2 and NRK cells and the production of reactive oxygen species caused by FNPs. The abnormal contents of oxidative stress indicators such as glutathione, superoxide dismutase, malondialdehyde, and catalase in HepG-2 and NRK cells induced by FNPs were alleviated due to the presence of HSA. These results suggested that the protein coronas formed by HSA on FNPs mitigated the cytotoxicity compared with the bare FNPs, thus providing insights into the interaction of squid FNPs with HSA.

Bovine lactoferrin and Lentinus edodes mycelia polysaccharide complex: The formation and the activity to protect islet β cells

The formation of complexes may be used for the development of delivery systems in foods field. The aim of this study was to explore the interaction mechanism between Lentinus edodes mycelia polysaccharide (LMP) and bovine lactoferrin (BLF), and the activity of LMP-BLF complex to inhibit oxidative stress in islet β cells. The interaction mechanisms of LMP with BLF were investigated with multi-spectroscopic techniques. The multi-spectroscopic analysis result showed that LMP bound with BLF by van der Waals force and hydrogen bond. The quenching mechanism of BLF with LMP was static quenching. Cell viability, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with thiazolyl blue tetrazolium bromide (MTT) assay, 2,7-Dichlorofluorescin diacetate (DCFH-DA) staining, Hoechst 33258 staining and Western blot methods respectively. The complex alleviated apoptosis induced by hydrogen peroxide (H₂O₂), and inhibited oxidative stress via MAPK pathways in MIN6 cells. In addition, the complex was able to promote glucose uptake in HepG2 cells. These results will broaden our understanding of LMP-BLF complexes and the applications of polysaccharide-protein complexes in the foods field.

Formation and biological effects of protein corona for food-related nanoparticles

The rapid development of nanoscience and nanoengineering provides new perspectives on the composition of food materials, and has great potential for food biology research and applications. The use of nanoparticle additives and the discovery of endogenous nanoparticles in food make it important to elucidate in vivo safety of nanomaterials. Nanoparticles will spontaneously adsorb proteins during transporting in blood and a protein corona can be formed on the nanoparticle surface inside the human body. Protein corona affects the physicochemical properties of nanoparticles and the structure and function of proteins, which in turn affects a series of biological reactions. This article reviewed basic information about protein corona of food-related nanoparticles, elucidated the influence of protein corona on nanoparticles properties and protein structure and function, and discussed the effect of protein corona on nanoparticles in vivo. The effects of protein corona on nanoparticles transport, cellular uptake, cytotoxicity, and immune response were reviewed, and the reasons for these effects were also discussed. Finally, future research perspectives for food protein corona were proposed. Protein corona gives food nanoparticles a new identity, which makes proteins bound to nanoparticles undergo structural transformations that affect their recognition by receptors in vivo. It can have positive or negative impacts on cellular uptake and toxicity of nanoparticles and even trigger immune responses. Understanding the effects of protein corona have potential in evaluating the fate of the food-related nanoparticles, providing physicochemical and biological information about the interaction between proteins and foodborne nanoparticles. The review article will help to evaluate the safety of protein coronas formed on nanoparticles in food, and may provide fundamental information for understanding and controlling nanotoxicity.

Interaction of Carbon Dots from Grilled Spanish Mackerel with Human Serum Albumin, γ-Globulin and Fibrinogen

The potential biological effects of food-borne carbon dots (FCDs) generated during food heating procedures on human health has received great attention. The FCDs will be inevitably exposed to blood proteins along with our daily diet to produce unknown biological effects. In this study, the interaction between FCDs extracted from grilled Spanish mackerel and three main types of human plasma proteins including human serum albumin (HSA), human γ-globulin (HGG) and human fibrinogen (HF) was reported. It was found that the grilled Spanish mackerel FCDs could affect the morphology, size and surface electrical properties of the three proteins. The interaction between the FCDs and proteins had different effects on the secondary structure of the three proteins through a static mechanism. The tested HSA, HGG, and HF could adsorb FCDs to reach saturation state within 0.5 min after the adsorption happened. The binding affinity of the FCDs to the plasma proteins was sorted as follows: HF > HGG > HSA. The results of FCDs interacted with plasma proteins provided useful information in the assessment of the safety of FCDs in our daily diet.

Zinc delivery system constructed from food-borne nanoparticles derived from Undaria pinnatifida

Food-borne nanoparticles from Undaria pinnatifida (UPFNs) were prepared and successfully applied as nanocarriers for microelement zinc delivery. UPFNs were spherical nanoparticles with average sizes of about 4.07 ± 1.09 nm, which chelated with zinc ions through amino nitrogen and carboxyl oxygen atoms as characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Thermodynamic analysis revealed that the overall chelation process between UPFNs and zinc ions was a spontaneous enthalpy-driven endothermic reaction. Compared to zinc sulfate, UPFN-Zn2+ showed higher solubility both in phytic acid solution and the process of gastrointestinal digestion. Meanwhile, no obvious cytotoxicity was found in UPFNs and UPFN-Zn2+. Specifically, UPFN-Zn2+ could successfully rescue cell viability, DNA replication activity and restore cell proliferation ability in zinc-deficient cells induced by a specific zinc chelator TPEN. Overall, UPFNs might serve as efficient, stable, and safe nanocarriers for zinc delivery.

Advances of microfluidic intestine-on-a-chip for analyzing anti-inflammation of food

Microfluidic intestine-on-a-chip enables novel means of emulating human intestinal pathophysiology in vitro, which can potentially reduce animal testing and substitute simple 2D culture system. Though a great deal of work has been done in the development of microfluidic platforms for intestinal disease modeling and drug screening, potential investigation of the effect of bioactive food compounds on intestinal inflammation remains largely unexplored. In this review, different biomaterials and chip designs have been explored in the fabrication of intestine-on-a-chip. Other key parameters must be carefully controlled and selected, including shear stress, cell type and cell co-culture spatial configuration, etc. Appropriate techniques to quantify the barrier integrity including trans-epithelial electric resistance, specific tight junction markers and permeability measurements should be standardized and compared with in vivo data. Integration of the gut microbiome and the provision of intestinal-specific environment are the key parameters to realize the in vivo intestinal model simulation and accelerate the screening efficiency of bioactive food compounds.