Facile preparation of hollow covalent organic frameworks as superior and universal matrix clean-up micro-structures for high throughout determination of food hazards.

The complicated food matrix seriously limits the one-time test for the potential food hazards in non-targeted analysis. Accordingly, developing advanced sample pretreatment strategy to reduce matrix effects is of great significance. Herein, newly-integrated hollow-structured covalent organic frameworks (HCOFs) with large internal adsorption capacity and target-matched pore size were synthesized via etching the core-shell structured COFs. The as-prepared HCOFs could be directly applied for matrix clean-up of vegetable samples, while further modification of polydopamine (PDA) network facilitated application for animal samples. Both HCOFs and HCOFs@PDA with the comparable sizes to the matrix interference gave excellent adsorption performance to targets, achieving satisfied recoveries (70%-120%) toward 90 pesticides and 44 veterinary drugs in one-test, respectively. This work showed the great potential of the facile-integrated HCOFs with high stability and customized size to remove interference matrix and offered a universal strategy to achieve simultaneous screening of hazards with considerable quantity in high-throughput non-targeted analysis.

Ferroptosis Contributes to Microvascular Dysfunction in Diabetic Retinopathy.

Ferroptosis is a new form of cell death characterized by iron-dependent lipid peroxidation. Whether ferroptosis is involved in retinal microvascular dysfunction under diabetic condition is not known. Herein, the expression of ferroptosis-related genes in patients with proliferative diabetic retinopathy and in diabetic mice was determined with quantitative RT-PCR. Reactive oxygen species, iron content, lipid peroxidation products, and ferroptosis-associated proteins in the cultured human retinal microvascular endothelial cells (HRMECs) and in the retina of diabetic mice were examined. The association of ferroptosis with the functions of endothelial cells in vitro was evaluated. After administration of ferroptosis-specific inhibitor, Fer-1, the retinal microvasculature in diabetic mice was assessed. Characteristic changes of ferroptosis-associated markers, including glutathione peroxidase 4, ferritin heavy chain 1, long-chain acyl-CoA synthetase 4, transferrin receptor protein 1, and cyclooxygenase-2, were detected in the retinal fibrovascular membrane of patients with proliferative diabetic retinopathy, cultured HRMECs, and the retina of diabetic mice. Elevated levels of reactive oxygen species, lipid peroxidation, and iron content were found in the retina of diabetic mice and in cultured HRMECs. Ferroptosis was found to be associated with HRMEC dysfunction under high-glucose condition. Inhibition of ferroptosis with specific inhibitor Fer-1 in diabetic mice significantly reduced the severity of retinal microvasculopathy. Ferroptosis contributes to microvascular dysfunction in diabetic retinopathy, and inhibition of ferroptosis might be a promising strategy for the therapy of early-stage diabetic retinopathy.

Integrative Analysis of miRNA and circRNA Expression Profiles and Interaction Network in HSV-1-Infected Primary Corneal Epithelial Cells.

PURPOSE: Circular RNAs (circRNAs) are products of alternative splicing with roles as competitive endogenous RNAs or microRNA sponges, regulating gene expression and biological processes. However, the involvement of circRNAs in herpes simplex keratitis remains largely unexplored. METHODS: This study examines circRNA and miRNA expression profiles in primary human corneal epithelial cells infected with HSV-1, compared to uninfected controls, using microarray analysis. Bioinformatic analysis predicted the potential function of the dysregulated circRNAs and microRNA response elements (MREs) in these circRNAs, forming an interaction network between dysregulated circRNAs and miRNAs. RESULTS: A total of 332 circRNAs and 16 miRNAs were upregulated, while 80 circRNAs and six miRNAs were downregulated (fold change ≥2.0 and p < 0.05). Gene ontology (GO) and KEGG pathway analyses were performed on parental genes of dysregulated circRNAs to uncover potential functions in HSV-1 infection. Notably, miR-181b-5p, miR-338-3p, miR-635, and miR-222-3p emerged as pivotal miRNAs interacting with multiple dysregulated circRNAs. CONCLUSIONS: This comprehensive study offers insights into differentially expressed circRNAs and miRNAs during HSV-1 infection in corneal epithelial cells, shedding light on circRNA-miRNA interactions' potential role in herpes simplex keratitis pathogenesis.

Hollow-structured molecularly imprinted polymers enabled specific enrichment and highly sensitive determination of aflatoxin B1 and sterigmatocystin against complex sample matrix.

The biotoxins with high toxicity have the potential to be manufactured into biochemical weapons, seriously threatening international public security. Developing robust and applicable sample pretreatment platforms and reliable quantification methods has been recognized as the most promising and practical approach to solving these problems. Through the integration of the hollow-structured microporous organic networks (HMONs) as the imprinting carriers, we proposed a molecular imprinting platform (HMON@MIP) with enhanced adsorption performance in terms of specificity, imprinting cavity density as well as adsorption capacity. The HMONs core of MIPs provided a hydrophobic surface that enhanced the adsorption of biotoxin template molecules during the imprinting process, resulting in an increased imprinting cavity density. The HMON@MIP adsorption platform could produce a series of MIP adsorbents by changing the biotoxin template, such as aflatoxin and sterigmatocystin, and showed promising generalizability. The limits of detection (LOD) of the HMON@MIP-based preconcentration method for AFT B1 and ST were 4.4 and 6.7 ng L-1, respectively, and the method was applicable to food sample with satisfied recoveries of 81.2-95.1%. And the specific recognition and adsorption sites left on HMON@MIP by the imprinting process can achieve outstanding selectivity for AFT B1 and ST. The developed imprinting platforms hold great potential for application in the identification and determination of various food hazards in complex food sample matrices and contribute to precise food safety inspection.

Functional Micro-/Nanostructures in Agrofood Science: Precise Inspection, Hazard Elimination, and Potential Health Risks.

Nanotechnology, biotechniques, and chemical engineering have arisen as new trends with significant impacts on agrofood science development. Advanced analytical techniques with high sensitivity, specificity, and automation based on micro-/nanomaterials for food hazard elimination have become leading research hotspots in agrofood science. Research progress in micro-/nanomaterials has provided a solid theoretical basis and technical support to solve problems in the industry. However, the rapid development of micro-/nanostructures has also raised concerns regarding potential risks to human health. This review presents the latest advances in the precise inspection and elimination of food hazards from micro-/nanomaterials and discusses the potential threats to human health posed by nanomaterials. The theoretical reference was provided for the application trend of micro-/nanomaterials in the field of agrofood science in the future.

ZIF-8 sacrificial-templated hollow COF architectures enabled highly efficient enrichment, determination and regulation of food hazards from infant formulas.

Integration of functional micro-/nano-frameworks with various analytical techniques is favored to produce advanced and practical methods for identification, inspection, and regulation of hazards in agro-food products. Herein, two novel synthetic strategies were developed for preparation of core-shell structured ZIF-8@COF by using metal halides as the catalyst, and further construction of hollow-structured covalent organic frameworks (HCOFs) with a sacrificial template method. The HCOFs adsorbent exhibited high stability, universality and adsorption affinity for advanced glycation end products (AGEs) and aflatoxins (AFTs) than pristine COF. Combined with HPLC and HPLC-MS/MS, the applicability of this method was verified by infant formula samples with satisfying recoveries of 87.3%-98.9%. Furthermore, HCOF showed potential ability of adsorbing and removing AGEs from plasma without causing other risk. This work opens up the road for further research on the simple method to synthesis HCOF, besides, provides a technological basis for monitoring and controlling AGEs and AFTs in milk powder.

Differential regulation and preventive mechanisms of green tea powder with different quality attributes on high-fat diet-induced obesity in mice.

Tea powder has been reported to have some physiological functions. However, there is no report on whether there are differences in the active ingredients of tea powder with different qualities and whether there are different prebiotic mechanisms. This study was aimed to investigate the effects of different qualities of tea powder on preventing obesity from different aspects, namely antioxidation, inflammation, lipid-lowering, and intestinal flora, using an obesity mouse model. The results showed that all three types of tea powder with different qualities could reduce body weight and decrease serum TC, TG, and LDL-C. However, tea powder with different quality attributes exhibited diverse modulatory effects and mechanisms. Tender tea powder contained more tea polyphenols, and it had a better effect on improving oxidative stress. Tender tea powder significantly decreased the abundances of Blautia, Bilophila, and Oscillibacter, and increased the abundances of Alloprevotella, Lachnoclostridium, Romboutsia, and Ruminococcaceae_UCG-004. Coarse tea powder contained more dietary fiber, and had a better effect on reducing the food intake and improving lipid metabolism, which could reduce lipid synthesis and increase lipid ß-oxidation. Coarse tea powder significantly decreased the abundance of Dubosiella and increased the abundances of the Lachnospiraceae_NK4A136 group and Coriobacteriaceae_UCG-002. Our findings provide a theoretical reference for the comprehensive utilization of tea powder.

A visual and reversible nanoprobe for rapid and on-site determination of hexavalent chromium and lysine based on dual-emission carbon quantum dots coupled with smartphone.

A straightforward, largely instrument-free, smartphone-based analytical strategy for hexavalent chromium and lysine (Lys) on-site detection via exploitation of dual-emission carbon quantum dots (DECQDs) has been demonstrated. DECQDs show dual-emission peaks at 439 and 630 nm with the excitation at 375 nm. As a dual-mode detection probe, the fluorescence and ultraviolet adsorption spectra of DECQDs vary with hexavalent chromium concentrations. Most importantly, Lys can restore the fluorescence of the hexavalent chromium added DECQD nanoprobe and change the color of the probe under natural light. At the same time, based on the participation of smartphones, the prepared DECQD probes favor the establishment of visual smart sensors that can also be used for the in-situ detection of targets. The on-site quantitative analysis exhibited a linear range of 5.3-320 µM with a detection limit of 1.6 µM towards Cr(VI) and the differentiation of Lys variation from 1 to 75 mM with a detection limit of 0.3 mM. The probe has been applied for the first time to enable vision-based colorimetric in complex samples such as water, milk and egg. The recoveries of Cr(VI) and Lys in real samples were between 90 and 104%, and the relative standard deviation (RSD) was as low as 0.4%. This work offers new perspectives for fundamental understanding and new design of functional luminescent materials that are applicable for food-safety and rapid and intelligent inspection. A straightforward, large instrument-free, smartphone-based analytical strategy with dual-emission carbon quantum dots was developed for hexavalent chromium and Lys on-site detection via fluorescent and colorimetric twofold readout measure.

Facile preparation of uniform-sized covalent organic framework nanoflowers as versatile sample-pretreatment platforms for sensitive and specific determination of hazardous substances.

Covalent-organic frameworks (COFs) have lately received extensive interest for their outstanding performance, especially to adsorption of hazards, while easy-preparation of uniform-sized COFs hold a great challenge. This research presented a simple synthesis method of flower-shaped COF (nanoflower) with strong hydrophobic surface at room temperature. Taking advantage of its easy-prepared and uniform-sized features, we proposed a versatile and efficient sample-pretreatment platform by employing the nanoflower COF for affinity adsorption of various hydrophobic biotoxins and further surface imprinting for selective enrichment of specific biotoxin (COF@MIP), respectively. The COF@MIP was integrating COF with molecular imprinting technique to achieve selective identification of sterigmatocystin (ST) with high specificity and sensitivity. They both exhibited well reusability, preserving 81% of initial activity after being used for six cycles. The as-prepared materials coupled with offline solid phase extraction (SPE) and high performance liquid chromatography (HPLC) were successfully applied to five common cereals with good recoveries in the range of 70.3-100.7%. Moreover, the principle of versatile sample pretreatment and detection platform based on the facile-prepared and uniform-sized COF nanoflower would be easily extended to other hazards. It provided a prospective approach for the pretreatment and determination of hazardous substances with low level in complex sample matrix.

Effects of Air Frying on French Fries: The Indication Role of Physicochemical Properties on the Formation of Maillard Hazards, and the Changes of Starch Digestibility.

This study focused on the formation of Maillard hazards in air fried fries, highlighting the correlation between the resultant physical properties of the fries and the formation of Maillard hazards. In the meantime, the effects of air frying on the in vitro starch digestibility of fries were explored. Potato strips were fried at various temperatures (180-200°C) and time (12-24 min). Results indicated that the extent of browning, hardness, and the contents of Maillard hazards (acrylamide, 5-hydroxymethylfurfural, methylglyoxal, and glyoxal) all increased steadily with air frying temperature and time. Moisture content were negatively correlated (p < 0.001) with Maillard hazards content and physicochemical properties except for L* with the correlation coefficients range from -0.53 to 0.94, and positively correlated with L* value with correlation coefficient was 0.91, hence, reducing the Maillard hazard exposure while maintaining the desired product quality can be achieved by controlling the moisture content of the air fried French fries. Compared with deep frying (180°C-6 min), air frying decreased acrylamide and 5-hydroxymethylfurfural content with the maximum reduction rate were 47.31 and 57.04%, respectively. In addition, the in vitro digestion results suggested that air frying resulted in higher levels of slowly digestible starch (48.54-58.42%) and lower levels of resistant starch (20.08-29.34%) as compared to those from deep frying (45.59 ± 4.89 and 35.22 ± 0.65%, respectively), which might contribute to more balanced blood sugar levels after consumption. Based on the above results, it was concluded that air frying can reduce the formation of food hazards and was relatively healthier.

Current Advances in Structure-Function Relationships and Dose-Dependent Effects of Human Milk Oligosaccharides.

HMOs (human milk oligosaccharides) are the third most important nutrient in breast milk. As complex glycans, HMOs play an important role in regulating neonatal intestinal immunity, resisting viral and bacterial infections, displaying anti-inflammatory characteristics, and promoting brain development. Although there have been some previous reports of HMOs, a detailed literature review summarizing the structure-activity relationships and dose-dependent effects of HMOs is lacking. Hence, after introducing the structures and synthetic pathways of HMOs, this review summarizes and categorizes identified structure-function relationships of HMOs. Differential mechanisms of different structural HMOs utilization by microorganisms are summarized. This review also emphasizes the recent advances in the interactions between different health benefits and the variance of dosage effect based on in vitro cell tests, animal experiments, and human intervention studies. The potential relationships between the chemical structure, the dosage selection, and the physiological properties of HMOs as functional foods are vital for further understanding of HMOs and their future applications.

Integration of Metal-Organic Frameworks with Bi-Nanoprobes as Dual-Emissive Ratiometric Sensors for Fast and Highly Sensitive Determination of Food Hazards.

Functional nanoprobes which detect specific food hazards quickly and simply are still in high demand in the field of food-safety inspection research. In the present work, a dual-emission metal-organic framework-based ratiometric fluorescence probe was integrated to detect Cu2+ and Pb2+ with rapidness and ease. Specifically, quantum dots (QDs) and carbon quantum dots (CQDs) were successfully embedded into zeolitic imidazolate framework-67 (ZIF-67) to function as a novel ratiometric fluorescent sensing composite. The ratiometric fluorescence signal of CQDs/QDs@ZIF-67 was significantly aligned with the concentration of metal ions to give an extremely low detection limit of 0.3324 nM. The highly sensitive and selective CQDs/QDs@ZIF-67 composite showed potential for the rapid and cost-effective detection of two metal ions.

Hollow-Structured Microporous Organic Networks Adsorbents Enabled Specific and Sensitive Identification and Determination of Aflatoxins.

Aflatoxin (AFT) contamination, commonly in foods and grains with extremely low content while high toxicity, has caused serious economic and health problems worldwide. Now researchers are making an effort to develop nanomaterials with remarkable adsorption capacity for the identification, determination and regulation of AFT. Herein, we constructed a novel hollow-structured microporous organic networks (HMONs) material. On the basis of Fe3O4@MOF@MON, hydrofluoric acid (HF) was introduced to remove the transferable metal organic framework (MOF) to give hollow MON structures. Compared to the original Fe3O4@MOF@MON, HMON showed improved surface area and typical hollow cavities, thus increasing the adsorption capacity. More importantly, AFT is a hydrophobic substance, and our constructed HMON had a higher water contact angle, greatly enhancing the adsorption affinity. From that, the solid phase extraction (SPE-HPLC) method developed based on HMONs was applied to analyze four kinds of actual samples, with satisfied recoveries of 85-98%. This work provided a specific and sensitive method for the identification and determination of AFT in the food matrix and demonstrated the great potential of HMONs in the field of the identification and control of mycotoxins.

2'-Fucosyllactose Ameliorates Oxidative Stress Damage in d-Galactose-Induced Aging Mice by Regulating Gut Microbiota and AMPK/SIRT1/FOXO1 Pathway.

The imbalance of reactive oxygen species is the main cause in aging, accompanied by oxidative stress. As the most abundant in human milk oligosaccharides (HMOs), 2'-Fucosyllactose (2'-FL) has been confirmed to have great properties in immunity regulation and anti-inflammatory. The research on 2'-FL is focused on infants currently, while there is no related report of 2'-FL for the elderly. A d-galactose-induced accelerated aging model was established to explore the protective effect of 2'-FL on the intestines and brain in mice. In this study, 2'-FL significantly reduced oxidative stress damage and inflammation in the intestines of aging mice, potentially by regulating the sirtuin1 (SIRT1)-related and nuclear factor E2-related factor 2 (Nrf2) pathways. In addition, 2'-FL significantly improved the gut mucosal barrier function and increased the content of short-chain fatty acids (SCFAs) in the intestine. The gut microbiota analysis indicated that 2'-FL mainly increased the abundance of probiotics like Akkermansia in aging mice. Moreover, 2'-FL significantly inhibited apoptosis in the brains of aging mice, also increasing the expression of SIRT1. These findings provided a basis for learning the benefits of 2'-FL in the aging process.

Functional Hybrid Micro/Nanoentities Promote Agro-Food Safety Inspection.

The rapid development of nanomaterials has provided a good theoretical basis and technical support to solve the problems of food safety inspection. The combination of functionalized composite nanomaterials and well-known detection methods is gradually applied to detect hazardous substances, such as chemical residues and toxins, in agricultural food products. This review concentrates on the latest agro-food safety inspection techniques and methodologies constructed with the assistance of new hybrid micro/nanoentities, such as molecular imprinting polymers integrated with quantum dots (MIPs@QDs), molecular imprinting polymers integrated with upconversion luminescent nanoparticles (MIPs@UCNPs), upconversion luminescent nanoparticles combined with metal-organic frameworks (UCNPs@MOFs), magnetic metal-organic frameworks (MOFs@Fe3O4), magnetic covalent-organic frameworks (Fe3O4@COFs), covalent-organic frameworks doped with quantum dots (COFs@QDs), nanobody-involved immunoassay for fast inspection, etc. The presented summary and discussion favor a relevant outlook for further integrating various disciplines, like material science, nanotechnology, and analytical methodology, for addressing new challenges that emerge in agro-food research fields.

Construction of pH-Dependent Nanozymes with Oxygen Vacancies as the High-Efficient Reactive Oxygen Species Scavenger for Oral-Administrated Anti-Inflammatory Therapy.

It is of great significance to eliminate excessive reactive oxygen species (ROS) for treating inflammatory bowel disease (IBD). Herein, for the first time, a novel nanozyme NiCo2 O4 @PVP is constructed via a step-by-step strategy. Noticeably, the existence of oxygen vacancy in the NiCo2 O4 @PVP is helpful for capturing oxygenated compounds, while both redox couples of Co3+ /Co2+ and Ni3+ /Ni2+ will offer richer catalytic sites. As expected, the obtained NiCo2 O4 @PVP exhibits pH-dependent multiple mimic enzymatic activities. Benefiting from the introduction of polyvinylpyrrolidone (PVP), the NiCo2 O4 @PVP possesses good physiological stability and excellent biosafety in stomach and intestines' environment. Meanwhile, the NiCo2 O4 @PVP also presents strong scavenging activities to ROS in vitro, including • O2- , H2 O2 , as well as • OH. Furthermore, a dextran sodium sulfate (DSS)-induced colitis model is established for evaluating the anti-inflammatory activity of NiCo2 O4 @PVP in vivo. Based on the size-mediated and charge-mediated mechanisms, the nanozyme can pass through the digestive tract and target the inflamed site for oral-administrated anti-inflammatory therapy. More interestingly, compared with the model group, the expression levels of inflammatory factors (e.g., Interleukin- 6 (IL-6), Interleukin- 1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS)) in colon of mice show a significant decrease after nanozyme intervention, thereby inhibiting the development of IBD. In short, current work provides an alternative therapy for patients suffering from IBD.

Infrared Spectroscopy and Anharmonic Vibrational Analysis of (H2O-Krn)+ (n = 1-3): Hemibond Formation of the Water Radical Cation.

The hemibond is a nonclassical covalent bond formed between a radical (cation) and a closed shell molecule. The hemibond formation ability of water has attracted great interest, concerning its role in ionization of water. While many computational studies on the water hemibond have been performed, clear experimental evidence has been hardly reported because the hydrogen bond formation overwhelms the hemibond formation. In the present study, infrared photodissociation spectroscopy is applied to (H2O-Krn)+ (n = 1-3) radical cation clusters. The observed spectra of (H2O-Krn)+ are well reproduced by the anharmonic vibrational simulations based on the hemibonded isomer structures. The firm evidence of the hemibond formation ability of water is revealed.

Newly Constructed NiCo2O4 Derived from ZIF-67 with Dual Mimic Enzyme Properties for Colorimetric Detection of Biomolecules and Metal Ions.

Integration of novel bio-/nanostructures as effective sensing platforms is still of great significance for robust and rapid analysis. Herein, a novel metal-organic framework-derived NiCo2O4 was synthesized via a feasible templating method. Significantly, redox couples of both Ni3+/Ni2+ and Co3+/Co2+ provided richer oxidation-reduction reactions, thereby leading to an enhanced catalytic activity. Furthermore, NiCo2O4 as an enzyme mimic with peroxidase-like activity and oxidase-like activity could oxidize colorless thylbenzidine (TMB) to blue oxTMB in the absence of H2O2. Thus, a sensitive chromogenic sensing platform for detecting Fe2+, thiourea, cysteine (Cys), and epigallocatechin-3-gallate (EGCG) was proposed. The colorimetric detection methods exhibited great features of low limit of detection (LOD) and broad linear range. Owing to the complexation reaction, the chromogenic sensing system of TMB + NiCo2O4 + Cys achieved effective detection of Cu2+ and Mn2+ with the LODs of 0.0022 and 0.0181 mM, respectively. Developed detection methods with wide linear ranges of 0.008-0.1 mM for Cu2+ and 0.08-1 mM for Mn2+ had excellent practical potential. Similarly, the reaction system of TMB + NiCo2O4 + EGCG could achieve the colorimetric detection of Cu2+ and Fe3+. The great chromogenic sensing performance for detecting Cu2+ and Fe3+ with a broad linear range and a low LOD could be also realized.

[Physiological mechanisms and clinical research progress of cupping therapy].

Cupping therapy is an important part of traditional Chinese medicine, and its efficacy has been gradually accepted and confirmed by modern clinical medicine, but its physiological mechanisms have no consensus. In the present paper, we summarized the related mechanisms from results of both domestic and international researches which include 1) blood circulation promotion theory, 2) neurological reflex theory, 3) gate theory of pain, 4) inflammation-immune reaction theory and 5) skin tension increase theory. We also reviewed progresses of clinical researches about application of cupping therapy to cardiovascular diseases, chronic musculoskeletal pain, migraine and other painful symptoms, as well as arthritis which effects involve the above mentioned blood-circulation promotion, tension-increase, gate theory and inflammation-immune reaction, respectively. We believe that the mechanisms of cupping therapy are not independent and should be explored further from different perspectives.

Ratiometric determination of Cr(VI) based on a dual-emission fluorescent nanoprobe using carbon quantum dots and a smartphone app.

A simple dual-colour fluorescent nanoprobe has been designed composed of blue and yellow emission carbon quantum dots (CQDs). This system is inexpensive and easy to operate and was successfully employed for on-site measurements based on a smartphone app. The designed nanoprobe exhibited increased selectivity for Cr(VI), leading to a double stable response of the two CQDs. The dual-emission nanoprobe showed blue-violet fluorescence upon UV irradiation, and the fluorescent emission peaks were located at 418 nm and 552 nm. The blue light emission of CQDs was quenched with increasing Cr(VI) concentration due to the inner filter effect, whereas the yellow light emission was enhanced due to the aggregation-induced emission effect. The different responses of the dual emissions to Cr(VI) resulted in a fluorescent colour variation, thus enabling facile macroscopic visualization. With a smartphone, the change in the fluorescence colour could be observed more apparently than that of a single fluorescence nanoprobe, and the response increased linearly so that the nanoprobe could be applied to instantaneous measurements. Furthermore, the dual-emission nanoprobe was successfully employed for analysing food and water samples. Accurate concentrations were obtained by constructing a calibration plot using a fluorescence spectrometer and a smartphone app; the recoveries were 81.6% to 107.7%, and the relative standard deviation was below 3.6%. Therefore, this smartphone-integrated dual-emission detection system is promising as a new portable method for the on-site measurement of Cr(VI) ions. * Y-CQDs: yellow emission carbon quantum dots. B-CQDs: blue emission carbon quantum dots. B/Y-CQDs: a mixture of B-CQDs and Y-CQDs.