Titanium dioxide nanoparticles (TiO2 NPs) are widely used in industry as a white pigment (paints, paper industry and toothpastes), photocatalysts (environmental decontamination and photovoltaic ...cells), inorganic UV filter (sunscreens and personal care products) and as a food additive (E171) and antimicrobial food packaging material. Silver nanoparticles (Ag NPs) are used in photonics, microelectronics, catalysis and medicine due to their catalytic activity, magnetic and optical polarizability, electrical and thermal conductivities and enhanced Raman scattering. They also have antibacterial, antifungal and antiviral activities, as well as anti-inflammatory potential. The huge increase in the use of nano-based products, mainly metallic NPs, implies the presence of nanomaterials in the environment, and hence, the unintentional human ingestion through water or foods (gastrointestinal tract is the main pathway of NPs intake in humans).
The presence of TiO2 NPs and Ag NPs in seafood samples was firstly established using an ultrasound assisted enzymatic hydrolysis procedure and sp-ICP-MS analysis. Several clams, cockles, mussels, razor clams, oysters and variegated scallops, which contain TiO2 NPs and Ag NPs, were subjected to an in vitro digestion process simulating human gastrointestinal digestion in the stomach and in the small and large intestine to determine the bioaccessibility of these NPs. Caco-2 cells were selected as model of human intestinal epithelium for transport studies because of the development of membrane transporters that are responsible for the uptake of chemicals. Parameters as transepithelial electrical resistance (TEER) and permeability of Lucifer Yellow were studied for establishing cell monolayer integrity. TiO2 NPs and Ag NPs transport as well as total Ti and Ag concentrations passing through the gastrointestinal epithelial barrier model (0–2 h) were assessed by sp-ICP-MS and ICP-MS in several molluscs.
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•Moderate bioaccessibility ratios of TiO2 and Ag nanoparticles in commercial fresh and frozen bivalve molluscs.•TiO2 and Ag nanoparticles transport assay by Caco-2 cells successfully applied to bivalve molluscs.•High sensitivity of single particle ICP-MS for characterizing TiO2 and Ag nanoparticles.
Analysis of a large, structurally diverse Caco-2 permeability dataset using a variety of statistical techniques suggests that log
D and molecular weight are the most important factors in determining ...the permeability of drug candidates. The limit for log
D is shown to be dependent on molecular weight. These limits are shown to be potentially superior to current guidelines in increasing the chances of finding highly permeable compounds. When combined with suggested upper limits for lipophilicity suggested in the literature based on the avoidance of toxicology and other adverse effects, this helps define a lipophilicity range that is optimum for drug candidates.
Anthocyanins (ACNs) are a series of polyphenols found in plants with various biological activities. To overcome their instability toward external environments and provide more effective encapsulation ...method, anthocyanins-loaded nanoliposomes (AN) were firstly prepared by combining ethanol injection method with ultrasonication. This method was simple and safe which avoiding organic solvents. Good physicochemical characterizations of AN (0.15% w/v ACNs) including the encapsulation efficiency (EE, 91.1 ± 1.7%), mean particle size (53.8 ± 1.8 nm), ζ-potential (−42.7 ± 2.2 mV) and polydispersity index (PDI, 0.19 ± 0.02) were observed. The encapsulation of AN was confirmed by transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy. Nanoliposome encapsulation also enhanced the stability, cellular uptake and antioxidant activities of ACNs in vitro. It was demonstrated that the nanoliposomes prepared by this method were an efficient carriers for the delivery of ACNs, and the results expects to provide theories and practice guides for further applications of AN.
•Ethanol injection method with ultrasonication was firstly adopted in this research.•Anthocyanins-loaded nanoliposomes showed good physicochemical characterizations.•Nanoliposomes enhanced the stability and cellular uptake of anthocyanins.•Nanoliposomes improved antioxidant activity of anthocyanins in vitro.
Cellulose nanoparticles from a vegetable source (cellulose fiber) have been evaluated for future use as reinforcement of polymeric matrixes (e.g., biodegradable films). Cellulose nanoparticles have ...numerous advantages: they are inexpensive and biodegradable, and they originate from renewable sources. Here, cellulose nanofibers (CNFs) were isolated from banana peel by chemical (alkaline treatment and bleaching followed by acid hydrolysis with 0.1, 1, or 10% (v/v) H2SO4) and mechanical (high pressure homogenizer) treatments. Atomic Force Microscopy (AFM) analysis showed all treatments effectively isolated banana fibers at the nanometer scale (average diameter of 3.72 nm). CNFs displayed ζ-potential values ranging from −37.60 to −67.37 mV, which prevented their aggregation. CNFs had high crystallinity values, from 63.1 to 66.4%, which indicated they could be good reinforcing agents. FTIR results confirmed that the chemical and mechanical treatments removed the amorphous fractions. Regarding cytotoxicity, low CNF concentrations (50–500 μg/mL) did not cause cell death, but CNFs at concentrations above 1000 μg/mL significantly decreased cell viability. The use of different sulfuric acid concentrations provided more detailed knowledge of the treatment methods and CNF features, which could help to improve the CNF production process. The combination of chemical and mechanical treatments proved to be an efficient strategy to prepare CNFs from banana peels as a potential reinforcing agent of polymeric matrixes (e.g., food packaging).
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•CNFs were isolated from banana peel using acid and mechanical treatments.•CNFs showed no cytotoxic effect against Caco-2 at concentrations lower than 500 μg/mL.•Banana peel CNFs have potential application as reinforcing agent in polymeric matrices.
Lycopene is claimed to have numerous physiological benefits, but its poor water solubility, chemical instability, and low bioavailability limit its application in functional foods and health care ...products. In this study, lycopene-loaded emulsions containing oil droplets with different interfacial structures were prepared and then cross-linked using transglutaminase (TG) and/or calcium ions (Ca2+) to form emulsion gels. The oil droplets were first coated by interfacial layers comprised of whey protein isolate (WPI) and sodium alginate (SA). During emulsion preparation, the SA was added either before or after homogenization to create complex or layer-by-layer coatings, respectively. Subsequently, TG and Ca2+ were used to cross-link WPI and SA to form emulsion gels. The results show that double-crosslinking increased the gel strength and viscosity of the emulsion gels. The layer-by-layer emulsion gels were stronger and more viscous than the complex ones. The photochemical and gastrointestinal stability of lycopene encapsulated within the emulsion gels was higher than that of free lycopene. An MTT toxicity test showed that the emulsion gels exhibited no cytotoxicity to Caco-2 cells. The lycopene-loaded emulsion gels exhibited stronger anti-inflammatory activity on the Caco-2 cells than the control. In addition, the absorption of lycopene by the Caco-2 cells increased after encapsulation. This study provides a new approach of preparing edible soft materials to enhance the application of hydrophobic bioactives (like lycopene) in functional foods.
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•Emulsions were formed containing oil droplets with layer-by-layer or complex coatings.•These emulsions were then gelled by crosslinking with transglutaminase and/or Ca2+.•The layer-by-layer emulsion gels exhibited better functional properties.•The double-crosslinked emulsion gels improved the stability of lycopene.•The emulsion gels increased the bioaccessibility and bioactivity of lycopene.
The effects of starch blends used as a filled hydrogels (FH) on improving the stability and bioavailability of β-carotene. The starch blends were prepared from rice (R), potato (P), and quinoa (Q) ...starches with different granule sizes and physical properties. P, which forms very weak gels, was blended with R or Q to form a rigid gel with a fibrous network showing low tan δ values. Among the FH prepared with starch blends, PQ-FH showed a non-additive effect, resulting higher gel-forming ability and freeze–thaw stability than those of P-FH or Q-FH. In addition, the relatively high protective effect of PQ-FH for β-carotene in the FH can be explained by the action of P-FH, which was significantly stable at high temperature, and by the action of Q-FH, which was stable against pH changes. The retention rate of β-carotene after in vitro digestion was highest in Q-FH and lowest in P-FH. The low retention rate in P-FH was improved by starch blending, especially in PQ-FH. Although there were no significant differences in the apparent permeability of β-carotene in Caco-2 cells among FH samples, they all showed significant improvement in bioavailability compared to the β-carotene loaded emulsion (EM) used as a control. Starch blend-based FH can be an effective delivery system for functional materials with various industrial applications.
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•Starch blending altered thermal properties of native starch.•Starch blending improved gel strength of native starch.•Starch blend-based filled hydrogel (FH) improved thermal stability of β-carotene.•Starch blend-based FH increased retention rate of β-carotene in simulated GIT.
Ingestion of Porphyromonas gingivalis, a periodontal pathogen, disrupts the intestinal barrier in mice. However, the involvement of outer membrane vesicles (OMVs) secreted from P. gingivalis in the ...destruction of the intestinal barrier remains unclear. In this study, we tested the hypothesis that OMVs carrying gingipains, the major cysteine proteases produced by P. gingivalis, affects the intestinal barrier function. OMVs increased the permeability of the Caco-2 cell monolayer, a human intestinal epithelial cell line, accompanied by degradation of the tight junction protein occludin. In contrast, OMVs prepared from mutant strains devoid of gingipains failed to induce intestinal barrier dysfunction or occludin degradation in Caco-2 cells. A close histological examination revealed the intracellular localization of gingipain-carrying OMVs. Gingipain activity was detected in the cytosolic fraction of Caco-2 cells after incubation with OMVs. These results suggest that gingipains were internalized into intestinal cells through OMVs and transported into the cytosol, where they then directly degraded occludin from the cytosolic side. Thus, P. gingivalis OMVs might destroy the intestinal barrier and induce systemic inflammation via OMV itself or intestinal substances leaked into blood vessels, causing various diseases.
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•OMVs from Porphyromonas gingivalis increased permeability of Caco-2 monolayer.•Gingipains on OMVs is responsible for destruction of Caco-2 cell barrier.•Gingipains on OMVs degraded tight junction protein, occludin.•Porphyromonas gingivalis OMVs deliver gingipains into cytosol in Caco-2 cells.
Cholera is a highly contagious and lethal waterborne disease induced by an infection with Vibrio cholerae (V. cholerae) secreting cholera toxin (CTx). Cholera toxin subunit B (CTxB) from the CTx ...specifically binds with monosialo-tetra-hexosyl-ganglioside (GM1) found on the exterior cell membrane of an enterocyte. Bioinspired by the pathological process of CTx, we developed an electrochemical biosensor with GM1-expressing Caco-2 cell membrane (CCM) on the electrode surface. Briefly, the electrode surface was functionalized with CCM using the vesicle fusion method. We determined the CTxB detection performances of Caco-2 cell membrane-coated biosensor (CCB) using electrochemical impedance spectroscopy (EIS). the CCB had an excellent limit of detection of ∼11.46 nM and a detection range spanning 100 ng/mL - 1 mg/mL. In addition, the CCB showed high selectivity against various interfering molecules, including abundant constituents of intestinal fluid and various bacterial toxins. The long-term stability of the CCBs was also verified for 3 weeks using EIS. Overall, the CCB has excellent potential for practical use such as point-of-care and cost-effective testing for CTxB detection in developing countries.
Microplastics (MPs) pollution becomes an emergent threat to the ecosystem, and its joint effect with organic contaminants will cause more severe consequences. Recently, MPs has been observed in human ...feces, suggesting that we are exposed to an uncertain danger. In this study, the joint effect of polyethylene microplastics particles (PEMPs) and Tetrabromobisphenol A (TBBPA) on human gut was explored through the simulation experiment in vitro with human cell Caco-2 and gut microbiota. The toxicity of TBBPA and PEMPs on Caco-2 human cells was considered by physiological and biochemical indexes such as cell proliferation, cell cycle, reactive oxygen species, lactate dehydrogenase release, and mitochondrial membrane potential. Besides, microbial community diversity, community structure, and function changes of gut microbiota were investigated using Illumina 16S rRNA gene MiSeq sequencing to reveal the influence of TBBPA and PEMPs on human gut microbiota. The results indicated that both PEMPs and TBBPA would deteriorate the status of Caco-2 cells, and TBBPA played a major role in it; meanwhile, PEMPs affected Caco-2 cells at high concentrations. Particularly, TBBPA and PEMPs exhibited a joint effect on Caco-2 cells to a certain degree. TBBPA selectivity inhibited the growth of gram-positive bacteria such as Enterococcus and Lactobacillus, contributing to the thriving of gram-negative bacteria such as Escherichia and Bacteroides. The existence of PEMPs would enhance the proportion of Clostridium, Bacteroides, and Escherichia. Community composition changed dramatically with the interference of PEMPs and TBBPA; this was undesirable to the healthy homeostasis of the human gut. PICRUSt analysis determined both PEMPs and TBBPA interfered with the metabolism pathways of gut microbiota. Hence, the threat of MPs and TBBPA to humans should arouse vigilance.
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•The effects of PEMPs and TBBPA on the Caco-2 cells were assessed comprehensively.•PEMPs co-exposure exacerbated the TBBPA cytotoxicity while its solo effect was weak.•The change of gut microbiota caused by PEMPs and TBBPA may break the gut homeostasis.•PICRUSt showed metabolic pathways of gut microbes being disturbed by PEMPs and TBBPA.
Food-intestine interaction study has always been a hot topic in food science and nutrition due to diverse physiological functions of intestine. Compared to expensive animal models with limited ...screening capabilities, the simple, reliable and highly reproducible intestinal cell models are widely used in food-intestine interaction study. There are many functional cell models used to simulate the intestine in vitro, among which the Caco-2 cell model is one of the most widely used and classical models. Recently years, the differentiated Caco-2 cell model has been greatly developed due to the development of various technologies, which not only overcomes the limitations of the traditional model, but also further broadens its application.
This review aims to overview the current applications of the differentiated Caco-2 cell model as a specialized model of intestinal cells in vitro, as well as new approaches solving the existing challenges of utilization, which can guide its future trends in interaction between food factors and the intestine.
Key findings and conclusions: With high flexibility, high repeatability and low cost, the differentiated Caco-2 cell model has been applied to a variety of intestinal studies including intestinal absorption, intestinal transport, intestinal metabolism, intestinal barrier, intestinal immunity and intestinal adhesion. Furthermore, future study should break limitations of traditional models with the help of automation, biochemistry, molecular biology and cells co-culture, so as to make it more closer to the internal environment without sacrificing its simplicity and reliability, and more suitable for cost-effective large-scale analysis of food-intestine interaction.
•Caco-2 monolayer express some structural and functional characteristics of intestine.•Caco-2 cell models applied to nutrition absorption, transport and metabolism in gut.•Effects of food factors on intestinal functions were study using Caco-2 cell models.•Molecular biology and automation are future trends to optimize Caco-2 cell models.
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