MAPK4 facilitates angiogenesis by inhibiting the ERK pathway in non-small cell lung cancer.

Background: Angiogenesis plays an important role in the occurrence and development of non-small cell lung cancer (NSCLC). The atypical mitogen-activated protein kinase 4 (MAPK4) has been shown to be involved in the pathogenesis of various diseases. However, the potential role of MAPK4 in the tumor angiogenesis of NSCLC remains unclear. Methods: Adult male C57BL/6 wild-type mice were randomly divided into the control group and p-siMAPK4 intervention group, respectively. The cell proliferation was analyzed with flow cytometry and immunofluorescence staining. The vascular density in tumor mass was analyzed by immunofluorescence staining. The expressions of MAPK4 and related signaling molecules were detected by western blot analysis and immunofluorescence staining, and so on. Results: We found that the expression of MAPK4, which was dominantly expressed in local endothelial cells (ECs), was correlated with tumor angiogenesis of NSCLC. Furthermore, MAPK4 silencing inhibited the proliferation and migration abilities of human umbilical vein ECs (HUVECs). Global gene analysis showed that MAPK4 silencing altered the expression of multiple genes related to cell cycle and angiogenesis pathways, and that MAPK4 silencing increased transduction of the extracellular regulated protein kinases 1/2 (ERK1/2) pathway but not Akt and c-Jun n-terminal kinase pathways. Further analysis showed that MAPK4 silencing inhibited the proliferation and migration abilities of HUVECs cultured in tumor cell supernatant, which was accompanied with increased transduction of the ERK1/2 pathway. Clinical data analysis suggested that the higher expression of MAPK4 and CD34 were associated with poor prognosis of patients with NSCLC. Targeted silencing of MAPK4 in ECs using small interfering RNA driven by the CD34 promoter effectively inhibited tumor angiogenesis and growth of NSCLC in vivo. Conclusion: Our results reveal that MAPK4 plays an important role in the angiogenesis and development of NSCLC. MAPK4 may thus represent a new target for NSCLC.

Synthesis of 1,2,4,5-tetra-substituted benzenes via copper-catalyzed dimerization of γ,δ-unsaturated ketones.

An efficient cyclization for the synthesis of 1,2,4,5-tetra-substituted benzenes via copper catalyzed dimerization of γ,δ-unsaturated ketones has been described. This one-pot procedure employs the γ,δ-unsaturated ketones as the sole substrate with multiple C-C bond formation. This protocol features broad substrate scope and provides a facile and robust method to construct polysubstituted benzene derivatives under mild conditions.

The Epidemiological Characteristics and Spatiotemporal Clustering of Measles - China, 2005-2022.

Introduction: In recent years, the incidence of measles in China has consistently remained below 1 per 100,000 population, yet the disease has not been eliminated. This study aims to comprehensively analyze the epidemiological characteristics of measles from 2005 to 2022, identify high-risk populations and areas, and propose targeted interventions. Methods: We utilized data from the China Disease Prevention and Control Information System for our comprehensive analysis. Spatial autocorrelation was employed to examine the spatial clustering of measles, while spatiotemporal scanning analysis was used to detect spatiotemporal clustering to describe measles epidemiology during the study period. Results: Between 2005 and 2022, 732,218 measles cases were reported in China. Overall, the incidence of measles exhibited a downward trend, particularly during the periods of 2008-2011 and 2015-2022. In 2022, the incidence rate reached its historical low at 0.039 per 100,000 population. Measles predominantly affects young children. Since 2017, global spatial clustering has diminished, although hotspot areas persist in the western provinces. Spatial-temporal scanning identified a high-incidence cluster from 2005 to 2008, comprising 15 provinces in the western, central, and northern regions of China. Conversely, from 2016 to 2022, a low-incidence cluster was detected in the southern and central provinces. Conclusions: China has made significant progress in measles prevention and control. The recent low incidence and absence of substantial spatiotemporal clustering indicate that China is nearing measles elimination. However, there is a continuing need to enhance prevention and control efforts among very young children and in historic incidence hotspots in western provinces. Additionally, improving the diagnosis of vaccine-associated rash illnesses is essential.

Epidemiological Insights into Autoimmune Bullous Diseases in China: A Comprehensive Analysis.

OBJECTIVE: This study aims to conduct an extensive analysis of autoimmune bullous diseases, particularly pemphigus vulgaris and bullous pemphigoid, in Shanghai, China, from 2016 to 2023. It seeks to understand the demographic profiles, comorbidities, mortality rates, risk factors, and socioeconomic impacts associated with autoimmune bullous disease. METHODS: A cross-sectional study design was employed, enrolling 1,072 patients. Diagnostic measures included clinical manifestations, histopathology, direct immunofluorescence, and serologic tests. The study also involved a detailed socioeconomic analysis and evaluation of occupational risks. RESULTS: The findings highlight a significant occupational risk in industries requiring enhanced safety measures, with a notable prevalence of autoimmune bullous disease among workers in these sectors. A considerable portion of the patients were from low-income backgrounds with limited literacy, indicating the economic burden of autoimmune bullous disease. A key discovery of the study is the potential pathological link between autoimmune bullous disease and interstitial lung disease. CONCLUSION: This research, one of the first comprehensive studies on autoimmune bullous disease in China, underscores the need for targeted healthcare strategies and further investigation into autoimmune bullous disease, particularly its relationship with interstitial lung disease.

Epigenetics: Mechanisms, potential roles, and therapeutic strategies in cancer progression.

Mutations or abnormal expression of oncogenes and tumor suppressor genes are known to cause cancer. Recent studies have shown that epigenetic modifications are key drivers of cancer development and progression. Nevertheless, the mechanistic role of epigenetic dysregulation in the tumor microenvironment is not fully understood. Here, we reviewed the role of epigenetic modifications of cancer cells and non-cancer cells in the tumor microenvironment and recent research advances in cancer epigenetic drugs. In addition, we discussed the great potential of epigenetic combination therapies in the clinical treatment of cancer. However, there are still some challenges in the field of cancer epigenetics, such as epigenetic tumor heterogeneity, epigenetic drug heterogeneity, and crosstalk between epigenetics, proteomics, metabolomics, and other omics, which may be the focus and difficulty of cancer treatment in the future. In conclusion, epigenetic modifications in the tumor microenvironment are essential for future epigenetic drug development and the comprehensive treatment of cancer. Epigenetic combination therapy may be a novel strategy for the future clinical treatment of cancer.

The prognostic value of pretreatment 18F-FDG PET-CT parameters with peripheral blood markers in patients with de novo metastatic nasopharyngeal carcinoma.

BACKGROUND AND PURPOSE: To develop and validate a prognostic nomogram based on pretreatment 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET-CT)radiomics parameters and peripheral blood markers for risk stratification in patients with de novo metastatic nasopharyngeal carcinoma (dmNPC). MATERIALS AND METHODS: A total of 558 patients with dmNPC were retrospectively enrolled between 2011 and 2019. Eligible patients were randomly divided into training and validation cohorts (7:3 ratio). A Cox regression model was used to identify prognostic factors for overall survival (OS). The predictive accuracy and discriminative ability of the prognostic nomogram were determined using the concordance index (C-index) and calibration curve. RESULTS: Independent factors derived from multivariable analysis of the training cohort to predict death were lactate dehydrogenase levels, pretreatment Epstein-Barr virus DNA, total lesion glycolysis of locoregional lesions, number of metastatic lesions, and age, all of which were assembled into a nomogram with (nomogram B) or without PET-CT parameters (nomogram A). The C-index of nomogram B for predicting death was 0.70, which was significantly higher than the C-index values for nomogram A. Patients were then stratified into low- and high-risk groups based on the scores calculated using nomogram B for OS. The median OS was significantly higher in the low-risk group than in the high-risk group (69.60 months [95 % CI: 58.50-108.66] vs. 21.40 months [95 % CI: 19.20-23.90]; p＜0.01). All the results were confirmed in the validation cohort. CONCLUSION: The proposed nomogram including PET-CT parameters yielded accurate prognostic predictions for patients with dmNPC, enabling effective risk stratification for these patients.

Supramolecular Exchange Reaction in the Cavity of Naphthalene diimides Extended-Pillar[6]arene.

A new naphthalene diimides extended-pillar[6]arene 1 with a large cavity and rich host-guest complexation properties was synthesized in high yield. It can not only form 1:2 complexes with large size polycyclic aromatic hydrocarbons but also form 1:1:1 ternary complex with perylene and 2,7-diazapyrenium. Moreover, the supramolecular exchange reaction from a 1:2 host-guest complex 1•(G3)2 formed by 1 and perylene to a 1:1:1 ternary complex 1•G3•G5 formed by 1 with perylene and 2,7-diazapyrenium salt was also investigated by 1H NMR experiments as well as theoretically calculations.

Inducing One-Step Dehydrogenation of Magnesium Borohydride via Confinement in Robust Dodecahedral Nitrogen-Doped Porous Carbon Scaffold.

A dodecahedral activated N-doped porous carbon scaffold is synthesized and used for the nanoconfinement of Mg(BH4)2. The optimized mesoporous scaffold possesses an accumulated pore width of 2.65 nm, high specific surface area (3955.9 m2 g-1), and large pore volume (2.15 cm3 g-1), providing ample space for the confinement of Mg(BH4)2 particles and numerous surface active sites for interactions with the same. The confined Mg(BH4)2 system features a dehydrogenation onset temperature of 81.5 °C, an extremely high capacity of 10.2 wt% H2, and an almost single-step dehydrogenation profile. Moreover, the system exhibits superior capacity retention of 82.7% after 20 cycles at a moderate temperature of 250 °C. Precise activation control enables a transformation from microporous carbon materials to mesoporous ones, and hence the efficient nanoconfinement of Mg(BH4)2 and realization of one-step dehydrogenation. The evolution of borohydride intermediates is systematically revealed throughout the cycling process. Density functional theory calculations demonstrate defective N heteroatoms within the scaffold are vital in reducing the strength of B─H bonds, and the N-doped carbon can facilitate decomposition of the irreversible MgB12H12 intermediate. This study opens up new avenues for designing robust carbon scaffolds doped with heteroatoms and analyzing intermediate evolution in nanoconfined Mg-based borohydride systems.

Low risk of hepatitis B virus reactivation in membranous nephropathy patients with resolved infection undergoing rituximab-based regimens without antiviral prophylaxis.

INTRODUCTION: Patients with resolved hepatitis B virus infection undergoing rituximab are at risk of hepatitis B virus reactivation without antiviral prophylaxis. However, the risk in such patients treated with rituximab-based regimens for membranous nephropathy is not clear. We evaluated the risk of hepatitis B virus reactivation in membranous nephropathy patients with resolved infection undergoing rituximab-based regimens without antiviral prophylaxis. METHODS: Clinical data of 51 membranous nephropathy patients with resolved hepatitis B virus infection undergoing rituximab-based regimens without antiviral prophylaxis were retrospectively analyzed. Among these, 21 patients were followed for more than 1 year after rituximab discontinuation. The clinical data collected aimed to assess patients' responses and the risk of hepatitis B virus reactivation during and after rituximab treatment. RESULTS: 30/51 (58.8 %) patients reached complete or partial remission at 12 months. None of the patients experienced HBsAg seroreversion during rituximab treatment. Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase and total bilirubin levels, as well as the numbers of patients who exceeded the upper limits of normal for alkaline phosphatase and prothrombin time, did not show any statistically significant difference during rituximab-based therapy. Neither did the anti-HBs level, the number of patients with protective anti-HBs titers exceeding 10 U/L, nor the levels of CD19+ B cells, CD4+ T cells, CD8+ T cells, and natural killer cells. Among the 21 patients followed for 12 (ranging from 12 to 19) months after rituximab discontinuation, no hepatitis B virus reactivation was observed. The mean anti-HBs level and the number of patients with anti-HBs titers over 10 U/L did not show any statistically significant difference during the extended follow-up of 33 patient-years. Neither did the CD4+ T cell, CD8+ T cell, nor the natural killer cell counts. One patient presented with an ALT level that exceeded the baseline value by three times and reached above 100 U/L, accompanied by elevations in AST, GGT, and ALP levels. Meanwhile, the anti-HBs titer was 816.09 U/L, and HBsAg was negative. CONCLUSION: The administration of rituximab-based regimens in membranous nephropathy patients with hepatitis B virus resolved infection leads to a low risk of hepatitis B virus reactivation without antiviral prophylaxis. Patient's immune status, drug combination, rituximab strategy should be fully evaluated when considering antiviral prophylaxis therapy.

Microbiome Metabolomic Analysis of the Anxiolytic Effect of Baihe Dihuang Decoction in a Rat Model of Chronic Restraint Stress.

Purpose: The Baihe Dihuang decoction (BDD) is a representative traditional Chinese medicinal formula that has been used to treat anxiety disorders for thousands of years. This study aimed to reveal mechanisms of anxiolytic effects of BDD with multidimensional omics. Methods: First, 28-day chronic restraint stress (CRS) was used to create a rat model of anxiety, and the open field test and elevated plus maze were used to assess anxiety-like behavior. Enzyme-linked immunosorbent assay (ELISA), hematoxylin-eosin staining, and immunofluorescence staining were used to evaluate inflammatory response. Besides, 16S rRNA gene sequencing assessed fecal microbiota composition and differential microbiota. Non-targeted metabolomics analysis of feces was performed to determine fecal biomarkers, and targeted metabolomics was used to observe the levels of hippocampus neurotransmitters. Finally, Pearson correlation analysis was used to examine relationships among gut microbiota, fecal metabolites, and neurotransmitters. Results: BDD significantly improved anxiety-like behaviors in CRS-induced rats and effectively ameliorated hippocampal neuronal damage and abnormal activation of hippocampal microglia. It also had a profound effect on the diversity of microbiota, as evidenced by significant changes in the abundance of 10 potential microbial biomarkers at the genus level. Additionally, BDD led to significant alterations in 18 fecal metabolites and 12 hippocampal neurotransmitters, with the majority of the metabolites implicated in amino acid metabolism pathways such as D-glutamine and D-glutamate, alanine, arginine and proline, and tryptophan metabolism. Furthermore, Pearson analysis showed a strong link among gut microbiota, metabolites, and neurotransmitters during anxiety and BDD treatment. Conclusion: BDD can effectively improve anxiety-like behaviors by regulating the gut-brain axis, including gut microbiota and metabolite modification, suppression of hippocampal neuronal inflammation, and regulation of neurotransmitters.

Effect of applying carbodiimide combined with a two-step self-etch adhesive durability.

BACKGROUND: This study investigated the effect of carbodiimide (EDC) combined with Clearfil SE self-etch adhesive on the shear bond strength (SBS), crosslinking degree, denaturation temperature, and enzyme activity of dentin in vitro. MATERIALS AND METHODS: Collected human sound third molars were randomly divided into different groups with or without EDC treatment (0.01-1 M). The specimens (n = 16)were stored for 24 h (immediate) or 12 months (aging) before testing the SBS. Fine dentin powder was obtained and treated with the same solutions. Then the crosslinking degree, denaturation temperature (Td), and enzyme activity were tested. Statistical analysis was performed using a one-way analysis of variance (ANOVA) to compare the differences of data between groups (α = 0.05). RESULTS: There was a significant drop in immediate SBS and more adhesive fracture of 1.0 M EDC group, while there were no significant differences among the other groups. SEM showed a homogeneous interface under all treatments. After 12 months of aging, the SBS significantly decreased. Less decreases of SBS in the 0.3 and 0.5 M groups were found. Due to thermal and enzymatical properties consideration, the 0.3 and 0.5 M treatments also showed higher cross-link degree and Td with lower enzyme activity. CONCLUSION: 0.3 and 0.5 M EDC may be favorable for delaying the aging of self-etch bond strength for 12 months. But it is still needed thoroughly study.

Endocannabinoid Hydrolase Inhibitors: Potential Novel Anxiolytic Drugs.

Over the past decade, the idea of targeting the endocannabinoid system to treat anxiety disorders has received increasing attention. Previous studies focused more on developing cannabinoid receptor agonists or supplementing exogenous cannabinoids, which are prone to various adverse effects due to their strong pharmacological activity and poor receptor selectivity, limiting their application in clinical research. Endocannabinoid hydrolase inhibitors are considered to be the most promising development strategies for the treatment of anxiety disorders. More recent efforts have emphasized that inhibition of two major endogenous cannabinoid hydrolases, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), indirectly activates cannabinoid receptors by increasing endogenous cannabinoid levels in the synaptic gap, circumventing receptor desensitization resulting from direct enhancement of endogenous cannabinoid signaling. In this review, we comprehensively summarize the anxiolytic effects of MAGL and FAAH inhibitors and their potential pharmacological mechanisms, highlight reported novel inhibitors or natural products, and provide an outlook on future directions in this field.

Reconstruction of the extensor tendon on the dorsal pedis with a chimeric skin-aponeurosis flap from the groin region.

BACKGROUND: Complex defects involving the extensor tendon on the dorsal pedis have been reconstructed using multiple procedures. Skin coverage and tendon transfers have also been performed. This study aimed to present our experience using a chimeric skin-aponeurosis flap for one-stage reconstruction of composite soft-tissue defects on the dorsal pedis. METHODS: Between May 2017 and September 2020, 12 patients with these defects received total treatment using a chimeric groin flap. Based on the superficial circumflex iliac vessels, the skin paddle resurfaced the cutaneous defect, and the vascularised external oblique aponeurosis was rolled to form a tendon-like structure to simultaneously replace the absent segment of the extensor tendons. A suitable "Y" bifurcation was dissected to enlarge the vessel diameter. Single-stage reconstruction was performed using a set of vascular anastomoses at the recipient site. RESULTS: Flap survival was achieved without significant complications. The hammertoe deformity was completely removed. The average dimension of the skin paddle was 8.0 × 13.0 cm (range, 6.5 × 11.0-10.0 × 14.0 cm), and the mean size of the aponeurosis was 8.0 × 4.0 cm (range, 6.0 × 3.0-10.0 × 5.0 cm). At the last follow-up visit, no morbidity was observed at the donor site. Natural shapes and walking functions were successfully achieved with a protective sensation. CONCLUSION: The chimeric groin flap with sheets of external oblique aponeurosis is a great candidate for one-stage reconstruction of composite soft tissue loss on the dorsal pedis. This approach provides cosmetic coverage, allowing faster wound healing and reduced tendon adhesions.

Antinociceptive role of the thalamic dopamine D3 receptor in descending modulation of intramuscular formalin-induced muscle nociception in a rat model of Parkinson's disease.

Pain in Parkinson's disease (PD) has been validated as one of the major non-motor dysfunctions affecting the quality of life and subsequent rehabilitation. In the present study, we investigated the role of the dopamine D3 receptor in the thalamic mediodorsal (MD) and ventromedial (VM) nuclei mediated descending control of nociception and intramuscular (i.m.) 2.5% formalin-induced persistent muscle nociception. Paw withdrawal reflexes were measured in naive rats and rats subjected to PD induced by unilateral microinjection of 6 µg 6-OHDA into the rat striatum. Formalin-induced muscle nociception in phase 1, inter-phase, and phase 2 was significantly greater in PD rats compared to naive and vehicle-treated rats (P < 0.001). PD rats exhibited bilaterally mechanical hyperalgesia and heat hypoalgesia in formalin-induced muscle nociception. Microinjection of SK609, a dopamine D3 receptor agonist, at various doses (2.5-7.5 nmol/0.5 µl) into the thalamic VM nucleus dose-dependently prolonged heat-evoked paw withdrawal latencies in both naive and PD rats. Administration of SK609 to either the MD or VM nuclei had no effect on noxious mechanically evoked paw withdrawal reflexes. Pre-treatment of the thalamic MD nucleus with SK609 significantly attenuated formalin-induced nociception, and reversed mechanical hyperalgesia, but not heat hypoalgesia. Pre-treatment of the thalamic VM nucleus with SK609 inhibited formalin-induced nociception in the late phase of phase 2 (30-75 min) and heat hypoalgesia, but not mechanical hyperalgesia (P < 0.05). It is suggested that the dopamine D3 receptors in the thalamus play an antinociceptive role in the descending modulation of nociception. Activation of D3 receptors within the thalamic MD and VM nuclei attenuates descending facilitation and enhances descending inhibition in rats during PD.

Two polyketide synthase genes VpPKS10 and VpPKS33 regulated by VpLaeA are essential to the virulence of Valsa pyri.

Valsa pyri, the causal agent of pear canker disease, typically induces cankers on the bark of infected trees and even leads to tree mortality. Secondary metabolites (SMs) produced by pathogenic fungi play a crucial role in the pathogenic process. In this study, secondary metabolic regulator VpLaeA was identified in V. pyri. VpLaeA was found to strongly affect the pathogenicity, fruiting body formation and toxicity of SMs of V. pyri. Additionally, VpLaeA was also found to be required for the response of V. pyri to some abiotic stresses. Transcriptome data analysis revealed that many of differentially expressed genes were involved in the secondary metabolite biosynthesis (SMB). Among them, about one third of SMB core genes were regulated by VpLaeA at different periods. Seven differentially expressed SMB core genes (VpPKS9, VpPKS10, VpPKS33, VpNRPS6, VpNRPS7, VpNRPS16, and VpNRPS17) were selected for knockout. Two modular polyketide synthase (PKS) genes (VpPKS10 and VpPKS33), which were closely related to the virulence of V. pyri from the above seven genes were identified. Notably, VpPKS10 and VpPKS33 also affected the production of fruiting body of V. pyri, but didn't participate in the resistance of V. pyri to abiotic stresses. Overall, this study demonstrates the multifaceted biological functions of VpLaeA in V. pyri, and identifies two toxicity-associated PKS genes in Valsa species fungi for the first time.

Combined analysis of metabolomics and 16S rRNA sequencing for ankylosing spondylitis patients before and after secukinumab therapy.

OBJECTIVE: Alterations in gut microbiota have been implicated in the pathogenesis of ankylosing spondylitis (AS), but the underlying mechanisms remain elusive. This study aims to investigate changes in gut microbiota and metabolites in individuals with AS before and after treatment with secukinumab, to identify the biological characteristics specific to AS patients and investigate the potential biomarkers, for optimizing therapeutic strategies more effectively. METHODS: Fecal microbiome data were collected from 30 AS patients before and after secukinumab therapy and compared with data from 40 healthy controls (HC). Additionally, we analyzed the metabolic profile of both groups from plasma. RESULTS: Findings indicated that the treatment-induced changes in the composition of several crucial bacterial groups, including Megamonas, Prevotella_9, Faecalibacterium, Roseburia, Bacteroides, and Agathobacter. Post-treatment, these groups exhibited a distribution more akin to that of the healthy populations compared with their pretreatment status. We identified three gut microbial taxa, namely Prevotellaceae_bacterium_Marseille_P2831, Prevotella_buccae, and Elusimicrobiota, as potential biomarkers for diagnosing individuals at a higher risk of developing AS and assessing disease outcomes. Plasma metabolomics analysis revealed 479 distinct metabolites and highlighted three disrupted metabolic pathways. Integration of microbiome and metabolomics datasets demonstrated a significant degree of correlation, underscoring the impact of the microbiome on metabolic activity. CONCLUSION: Secukinumab can restore the balance of the gut microbiome and metabolites in AS patients, rendering them more similar to those found in the healthy population. The analysis of microbiome and metabolomics data have unveiled some candidate biomarkers capable of evaluating treatment efficacy.

Multimodal optoacoustic imaging: methods and contrast materials.

Optoacoustic (OA) imaging offers powerful capabilities for interrogating biological tissues with rich optical absorption contrast while maintaining high spatial resolution for deep tissue observations. The spectrally distinct absorption of visible and near-infrared photons by endogenous tissue chromophores facilitates extraction of diverse anatomic, functional, molecular, and metabolic information from living tissues across various scales, from organelles and cells to whole organs and organisms. The primarily blood-related contrast and limited penetration depth of OA imaging have fostered the development of multimodal approaches to fully exploit the unique advantages and complementarity of the method. We review the recent hybridization efforts, including multimodal combinations of OA with ultrasound, fluorescence, optical coherence tomography, Raman scattering microscopy and magnetic resonance imaging as well as ionizing methods, such as X-ray computed tomography, single-photon-emission computed tomography and positron emission tomography. Considering that most molecules absorb light across a broad range of the electromagnetic spectrum, the OA interrogations can be extended to a large number of exogenously administered small molecules, particulate agents, and genetically encoded labels. This unique property further makes contrast moieties used in other imaging modalities amenable for OA sensing.

An integrated smartphone-based electrochemical detection system for highly sensitive and on-site detection of chemical oxygen demand by copper-cobalt bimetallic oxide-modified electrode.

A portable and integrated electrochemical detection system has been constructed for on-site and real-time detection of chemical oxygen demand (COD). The system mainly consists of four parts: (i) sensing electrode with a copper-cobalt bimetallic oxide (CuCoOx)-modified screen-printed electrode; (ii) an integrated electrochemical detector for the conversion, amplification, and transmission of weak signals; (iii) a smartphone installed with a self-developed Android application (APP) for issuing commands, receiving, and displaying detection results; and (iv) a 3D-printed microfluidic cell for the continuous input of water samples. Benefiting from the superior catalytic capability of CuCoOx, the developed system shows a high detection sensitivity with 0.335 µA/(mg/L) and a low detection limit of 5.957 mg/L for COD determination and possessing high anti-interference ability to chloride ions. Moreover, this system presents good consistency with the traditional dichromate method in COD detection of actual water samples. Due to the advantages of cost effectiveness, portability, and point-of-care testing, the system shows great potential for water quality monitoring, especially in resource-limited remote areas.