RNAi-mediated knockdown of papilin gene affects the egg hatching in Nilaparvata lugens.

BACKGROUND: The brown planthopper (BPH), Nilaparvata lugens, is one of the most destructive pests of rice. Owing to the rapid adaptation of BPH to many pesticides and resistant varieties, identifying putative gene targets for developing RNA interference (RNAi)-based pest management strategies has received much attention for this pest. The glucoprotein papilin is the most abundant component in the basement membranes of many organisms, and its function is closely linked to development. RESULTS: In this study, we identified a papilin homologous gene in BPH (NlPpn). Quantitative Real-time PCR analysis showed that the transcript of NlPpn was highly accumulated in the egg stage. RNAi of NlPpn in newly emerged BPH females caused nonhatching phenotypes of their eggs, which may be a consequence of the maldevelopment of their embryos. Moreover, the transcriptomic analysis identified 583 differentially expressed genes between eggs from the dsGFP- and dsNlPpn-treated insects. Among them, the 'structural constituent of cuticle' cluster ranked first among the top 15 enriched GO terms. Consistently, ultrastructural analysis unveiled that dsNlPpn-treated eggs displayed a discrete and distorted serosal endocuticle lamellar structure. Furthermore, the hatchability of BPH eggs was also successfully reduced by the topical application of NlPpn-dsRNA-layered double hydroxide nanosheets onto the adults. CONCLUSION: Our findings demonstrate that NlPpn is essential to maintaining the regular structure of the serosal cuticle and the embryonic development in BPH, indicating NlPpn could be a potential target for pest control during the egg stage. © 2024 Society of Chemical Industry.

Immune checkpoint inhibitors: breakthroughs in cancer treatment.

Over the past two decades, immunotherapies have increasingly been considered as first-line treatments for most cancers. One such treatment is immune checkpoint blockade (ICB), which has demonstrated promising results against various solid tumors in clinical trials. Monoclonal antibodies (mAbs) are currently available as immune checkpoint inhibitors (ICIs). These ICIs target specific immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Clinical trial results strongly support the feasibility of this immunotherapeutic approach. However, a substantial proportion of patients with cancer develop resistance or tolerance to treatment, owing to tumor immune evasion mechanisms that counteract the host immune response. Consequently, substantial research focus has been aimed at identifying additional ICIs or synergistic inhibitory receptors to enhance the effectiveness of anti-PD-1, anti-programmed cell death ligand 1 (anti-PD-L1), and anti-CTLA-4 treatments. Recently, several immune checkpoint molecular targets have been identified, such as T cell immunoreceptor with Ig and ITIM domains (TIGIT), mucin domain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B and T lymphocyte attenuator (BTLA), and signal-regulatory protein α (SIRPα). Functional mAbs targeting these molecules are under development. CTLA-4, PD-1/PD-L1, and other recently discovered immune checkpoint proteins with distinct structures are at the forefront of research. This review discusses these structures, as well as clinical progress in mAbs targeting these immune checkpoint molecules and their potential applications.

Functional characterization of three novel dense granule proteins in Neospora caninum using the CRISPR-Cas9 system.

Neospora caninum is an obligate intracellular parasite that infects a wide range of mammalian species, and particularly causes abortions in cattle and nervous system dysfunction in dogs. Dense granule proteins (GRAs) are thought to play an important role in the mediation of host-parasite interactions and facilitating parasitism. However, a large number of potential GRAs remain uncharacterized, and the functions of most of the identified GRAs have not been elucidated. Previously, we screened a large number GRAs including NcGRA27 and NcGRA61 using the proximity-dependent biotin identification (BioID) technique. Here, we identified a novel GRA protein NcGRA85 and used C-terminal endogenous gene tagging to determine its localization at the parasitophorous vacuole (PV) in the tachyzoite. We successfully disrupted three gra genes (NcGRA27, NcGRA61 and NcGRA85) of N. caninum NC1 strain using CRISPR-Cas9-mediated homologous recombination and phenotyped the single knockout strain. The NcGRA61 and NcGRA85 genes were not essential for parasite replication and growth in vitro and for virulence during infection of mice, as observed by replication assays, plaque assays and in vitro virulence assays in mice. Deletion of the NcGRA27 gene in the NC1 strain reduced the in vitro replication and growth of the parasite, as well as the pathogenicity of the NC1 strain in mice. In summary, our findings provide a basis for in-depth studies of N. caninum pathogenesis and demonstrate the importance of NcGRA27 in parasite growth and virulence, most likely a new virulence factor of N. caninum.

Recognition of 3D Images by Fusing Fractional-Order Chebyshev Moments and Deep Neural Networks.

In order to achieve efficient recognition of 3D images and reduce the complexity of network parameters, we proposed a novel 3D image recognition method combining deep neural networks with fractional-order Chebyshev moments. Firstly, the fractional-order Chebyshev moment (FrCM) unit, consisting of Chebyshev moments and the three-term recurrence relation method, is calculated separately using successive integrals. Next, moment invariants based on fractional order and Chebyshev moments are utilized to achieve invariants for image scaling, rotation, and translation. This design aims to enhance computational efficiency. Finally, the fused network embedding the FrCM unit (FrCMs-DNNs) extracts depth features to analyze the effectiveness from the aspects of parameter quantity, computing resources, and identification capability. Meanwhile, the Princeton Shape Benchmark dataset and medical images dataset are used for experimental validation. Compared with other deep neural networks, FrCMs-DNNs has the highest accuracy in image recognition and classification. We used two evaluation indices, mean square error (MSE) and peak signal-to-noise ratio (PSNR), to measure the reconstruction quality of FrCMs after 3D image reconstruction. The accuracy of the FrCMs-DNNs model in 3D object recognition was assessed through an ablation experiment, considering the four evaluation indices of accuracy, precision, recall rate, and F1-score.

Phytochemical Profiling and Biological Activities of Pericarps and Seeds Reveal the Controversy on "Enucleation" or "Nucleus-Retaining" of Cornus officinalis Fruits.

The fruits of Cornus officinalis are used not only as a popular health food to tonify the liver and kidney, but also as staple materials to treat dementia and other age-related diseases. The pharmacological function of C. officinalis fruits with or without seeds is controversial for treating some symptoms in a few herbal prescriptions. However, the related metabolite and pharmacological information between its pericarps and seeds are largely deficient. Here, comparative metabolomics analysis between C. officinalis pericarps and seeds were conducted using an ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, and therapeutic effects were also evaluated using several in vitro bioactivity arrays (antioxidant activity, α-glucosidase and cholinesterase inhibitory activities, and cell inhibitory properties). A total of 499 secondary metabolites were identified. Thereinto, 77 metabolites were determined as key differential metabolites between C. officinalis pericarps and seeds, and the flavonoid biosynthesis pathway was identified as the most significantly different pathway. Further, 47 metabolites were determined as potential bioactive constituents. In summary, C. officinalis seeds, which demonstrated higher contents in total phenolics, stronger in vitro antioxidant activities, better α-glucosidase and butyrylcholinesterase inhibitory activities, and stronger anticancer activities, exhibited considerable potential for food and health fields. This work provided insight into the metabolites and bioactivities of C. officinalis pericarps and seeds, contributing to their precise development and utilization.

Highly Selective and Portable Fluorescence Turn-On Detection of Sc3+ in Ore and Water Based on Strong Lewis Acid-Base Coordination.

Detecting scandium (Sc) with high selectivity and sensitivity is a challenging task due to its chemical similarity to other rare earth ions. Our findings show that the fluorescence of the complex fluorescent indicator calcein (CL) is quenched under acidic conditions (pH = 2), and Sc3+ strongly inhibits this process. The results demonstrate that CL forms multimers and precipitates out of the solution under acidic conditions, while Sc3+ causes a significant decrease in the scattering intensity of the solution. Additional experiments revealed that the strong Lewis acid nature of Sc3+ complexes with the carboxyl groups of CL leads to increased dispersion of CL even under acidic conditions, thus enhancing its absorption and fluorescence. The complexation ratio of Sc3+ and CL was investigated through spectral titrations and theoretical calculations. The interaction between Sc3+ and CL is the strongest among rare earth and common metal ions due to the smallest ionic radius, resulting in high selectivity. The fluorescence turn-on strategy had a linear range of 0.04 to 2.25 µM under optimal conditions, with a detection limit of 20 nM for Sc3+. The combination of 3D printing and a smartphone program allows for portable on-site analysis of Sc3+. Mineral and water samples were used to demonstrate the potential of this strategy for the rapid, selective, and sensitive analysis of low levels of Sc3+.

Distribution of H2S in the 10103 excavation working face of the Baozigou coal mine.

Based on the production conditions of the 10103 excavation working face of the Baozigou coal mine, this paper analyzes the potential sources of H2S and the expected emission concentrations of H2S in the working face. Considering the previous engineering practice for controlling H2S disasters in coal mine working faces, numerical simulations were conducted to investigate air flow and H2S migration and diffusion in the tunnel in the excavation working face. The migration and distribution of H2S in the coal seam mining face were studied, and the effects of outlet wind speed, duct location, and duct diameter on the H2S concentration distribution were explored. The higher the outlet wind speed, the more conducive to the emission of H2S gas, but too high a wind speed will be detrimental to the concentrated extraction and purification absorption of H2S; the closer the outlet position of the air duct is to the end of the working surface, the lower the H2S concentration in the vortex area at the corner; the air duct If the diameter is too small, the harmful gases released from hard-to-break coal cannot be entrained and taken away. When the diameter of the air duct is too large, the entrainment volume during the jet process will be expanded. To verify the field distribution of H2S concentration at the bottom, middle, and top of the boring machine, a CD4-type portable H2S instrument was used to analyze the distribution of H2S near the excavation working face.

Portable purge and trap-microplasma optical emission spectrometric device for field detection of iodine in water.

Iodine is essential for human growth and can enter the body through food, water, and air. Analyzing its presence in the environment is crucial for ensuring healthy human development. However, current large-scale instruments have limitations in the field analysis of iodine. Herein, a miniaturized purge and trap point discharge microplasma optical emission spectrometric (P&T-µPD-OES) device was developed for the field analysis of iodine in water. Volatile iodine molecules were produced from total inorganic iodine (TII) through a basic redox reaction under acidic conditions, then the purge and trap module effectively separated and preconcentrated iodine molecules. The iodine molecules were subsequently atomized and excited by the integrated point discharge microplasma and an iodine atomic emission line at 206.24 nm was monitored by the spectrometer. Under optimal conditions, this proposed method had a detection limit of 16.2 µg L-1 for iodine and a precision better than 4.8%. Besides, the accuracy of the portable device was validated by successful analysis of surface and groundwater samples and a comparison of the mass spectrometry method. This proposed portable, low-power device is expected to support rapid access to iodine levels and distribution in water.

Research on the dust-control technology of a double-wall attached-ring air curtain on an excavation face.

On the basis of the jet theory of airflow fields and the gas-solid two-phase flow theory, we studied the law of dust migration in a simulated dusting space. We used the control variable method and numerical simulation software to explore the airflow field and dust concentration distribution on the working surface of the dusting under different inlet wind speeds and different attached blades of the double-walled annular air curtain. We determined the speed of the inlet of the annular air curtain to be 30 m/s. When the angle of the attached blade was 30°, the dust concentration of the driver and other workers was controlled below 100 mg/m3, which produced the best dust control effect is the best. Using real data, we built a similar test platform to test the airflow field and dust concentration. Through data measurement and analysis, we proved that a dust control system with a double-wall attached-ring air curtain formed a circulating airflow field that could shield dust and effectively reduce dust concentration in the simulated space. The dust removal efficiency of total dust and exhaled dust reached 98.5% and 97.5%, respectively. We compared the test data and simulation results and concluded that the double-wall attached-ring air curtain could effectively ensure the safety of mine production and provide a better underground working environment for operators.

Arsenic field test kits based on solid-phase fluorescence filter effect induced by silver nanoparticle formation.

Millions of people worldwide are affected by naturally occurring arsenic in groundwater. The development of a low-cost, highly sensitive, portable assay for rapid field detection of arsenic in water is important to identify areas for safe wells and to help prioritize testing. Herein, a novel paper-based fluorescence assay was developed for the on-site analysis of arsenic, which was constructed by the solid-phase fluorescence filter effect (SPFFE) of AsH3-induced the generation of silver nanoparticles (AgNPs) toward carbon dots. The proposed SPFFE-based assay achieves a low arsenic detection limit of 0.36 µg/L due to the efficient reduction of Ag+ by AsH3 and the high molar extinction coefficient of AgNPs. In conjunction with a smartphone and an integrated sample processing and sensing platform, field-sensitive detection of arsenic could be achieved. The accuracy of the portable assay was validated by successfully analyzing surface and groundwater samples, with no significant difference from the results obtained through mass spectrometry. Compared to other methods for arsenic analysis, this developed system offers excellent sensitivity, portability, and low cost. It holds promising potential for on-site analysis of arsenic in groundwater to identify safe well locations and quickly obtain output from the global map of groundwater arsenic.

Safety and feasibility of anti-CD19 CAR T cells expressing inducible IL-7 and CCL19 in patients with relapsed or refractory large B-cell lymphoma.

Although CD19-specific chimeric antigen receptor (CAR) T cells are curative for patients with relapsed or refractory large B-cell lymphoma (R/R LBCL), disease relapse with tumor antigen-positive remains a challenge. Cytokine/chemokine-expressing CAR-T cells could overcome a suppressive milieu, but the clinical safety and efficacy of this CAR-T therapy remain unclear. Here we report the preclinical development of CD19-specific CAR-T cells capable of expressing interleukin (IL)-7 and chemokine (C-C motif) ligand (CCL)-19 upon CD19 engagement (referred to as 7 × 19 CAR-T cells) and results from a phase 1 and expansion phase trial of 7 × 19 CAR-T cell therapy in patients with R/R LBCL (NCT03258047). In dose-escalation phase, there were no dose-limiting toxicities observed. 39 patients with R/R LBCL received 7 × 19 CAR-T with doses ranged from 0.5 × 106-4.0 × 106 cells per kg body weight. Grade 3 cytokine release syndrome occurred in 5 (12.8%) patients and ≥ grade 3 neurotoxicity in 4 (10.3%) patients. The overall response rate at 3 months post-single infusion was 79.5% (complete remission, 56.4%; partial response, 23.1%). With a median follow-up of 32 months, the median progression-free survival was 13 months, and median overall survival was not reached, with an estimated rate of 53.8% (95% CI, 40.3% to 72.0%) at two years. Together, these long-term follow-up data from the multicenter clinical study suggest that 7 × 19 CAR-T cells can induce durable responses with a median overall survival of greater than 2 years, and have a manageable safety profile in patients with R/R LBCL.

2D TiS2-Nanosheet-Coated Concave Gold Arrays with Triple-Coupled Resonances as Sensitive SERS Substrates.

Herein, a hybrid substrate for surface-enhanced Raman scattering (SERS) is fabricated, which couples localized surface plasmon resonance (LSPR), charge transfer (CT) resonance, and molecular resonance. Exfoliated 2D TiS2 nanosheets with semimetallic properties accelerate the CT with the tested analytes, inducing a remarkable chemical mechanism enhancement. In addition, the LSPR effect is coupled with a concave gold array located underneath the thin TiS2 nanosheet, providing a strong electromagnetic enhancement. The concave gold array is prepared by etching silicone nanospheres assembled on larger polystyrene nanospheres, followed by depositing a gold layer. The LSPR intensity near the gold layer can be adjusted by changing the layer thickness to couple the molecular and CT resonances, in order to maximize the SERS enhancement. The best SERS performance is recorded on TiS2-nanosheet-coated plasmonic substrates, with a detectable methylene blue concentration down to 10-13 m and an enhancement factor of 2.1 × 109 and this concentration is several orders of magnitude lower than that of the TiS2 nanosheet (10-11 m) and plasmonic substrates (10-9 m). The present hybrid substrate with triple-coupled resonance further shows significant advantages in the label-free monitoring of curcumin (a widely applied drug for treating multiple cancers and inflammations) in serum and urine.

Land Carrying Capacity in China: A Perspective on Food Nutritional Demand.

The sustainable and stable population support capacity of a country or region is of great concern. This study proposes a new method for evaluating the land carrying capacity (LCC) based on food nutrition demand and establishes a clear link between nutritional health and land. We delved into the evolving dynamics of food consumption and production structures in China between 1990 and 2020, with a focus on the spatial variations among its 31 provinces. The objectives of this study were to assess the status of LCC, identify the critical nutritional factors constraining LCC enhancement, and propose differentiated pathways for improving LCC. The results showed that: (1) There has been a steady increase in the annual consumption of animal-based products, while plant-based product consumption has declined. (2) Overall, food supply capacity has expanded, displaying an "east high, west low" trend, resulting in an imbalanced food supply level. (3) The LCC for energy and carbohydrates exhibited continuous fluctuating growth but displayed a declining trend after 2018. (4) The pressure on land carrying capacity has shifted from a state of "surplus" to "abundant surplus," signifying a safe food system level. However, significant spatial variations persist, leading to shortages and surpluses. Therefore, this work suggests that addressing these disparities requires the optimization of food consumption structures and increasing the supply of animal-based foods. This approach leverages regional advantages and reduces disparities in regional LCCs. This study provides a valuable reference for ensuring food security in response to unprecedented global changes in sustainable development.

Portable and Rapid Fluorescence Turn-On Detection of Total Pepsin in Saliva Based on Strong Electrostatic Interactions.

Salivary pepsin has been proposed as a promising diagnostic marker for gastroesophageal reflux disease (GERD). However, the activity of human pepsin is strongly influenced by pH, and the acidic condition (pH ∼ 2) is optimal, which is a contradiction for the pepsin detection kit based on its catalytic activity. Thus, its accurate quantification in saliva (neutral pH) by readily rapid tools with simplicity and low cost is still challenging. Herein, a convenient fluorescence assay has been developed for the rapid detection of pepsin at neutral pH based on its electrostatic interaction with SYBR Green (SG) rather than the bioactivity. At neutral pH, the positively charged SG fluorophore can be effectively adsorbed by the negatively charged pepsin due to the low isoelectric point (pI) and large molecular size of pepsin. Thus, the molecular rotation of SG is limited, and its fluorescence intensity is significantly increased. The strategy was further confirmed to have the same fluorescence response as that of normally active and inactivated pepsin. Due to the unique pI of pepsin, the fluorescence strategy is highly selective for pepsin compared to other proteins. On the basis of this strategy, a smartphone-based fluorescence capture device integrated with a programmed Python program was fabricated for both color recognition and the accurate detection of pepsin within 3 min. Under the optimal conditions, this turn-on sensor allowed for the on-site analysis of pepsin with a detection limit of 0.2 µg/mL. Moreover, this strategy was successfully used to assess salivary pepsin to aid in the noninvasive diagnosis of GERD.

Molecular Simulation of Coal Molecular Diffusion Properties in Chicheng Coal Mine.

In order to study the importance of the diffusion mechanism of CH4 and CO2 in coal for the development of coalbed methane, the aim of this paper is to reveal the influence mechanism of pressure, temperature, water content and other factors on the molecular diffusion behavior of gas at the molecular level. In this paper, non-sticky coal in Chicheng Coal Mine is taken as the research object. Based on the molecular dynamics method (MD) and Monte Carlo (GCMC) method, the diffusion characteristics and microscopic mechanism of CH4 and CO2 in coal under different pressures (100 kPa-10 MPa), temperatures (293.15-313.15 K) and water contents (1-5%) were analyzed in order to lay a theoretical foundation for revealing the diffusion characteristics of CBM in coal, and provide technical support for further improving CBM extraction. The results show that high temperature is conducive to gas diffusion, while high pressure and water are not conducive to gas diffusion in the coal macromolecular model.

Mycobacterium tuberculosis Mce2D protein blocks M1 polarization in macrophages by inhibiting the ERK signaling pathway.

Macrophages play a pivotal role in controlling Mycobacterium infection, and the pathogen thrives in the event of immune evasion and immunosuppression of macrophages. Mammalian cell entry proteins (Mce) are required for Mycobacterium tuberculosis (M. tb) growth and the host cell's initial phagocytosis and cytokine response. Mce2D protein is one of a family of proteins that infect M. tb; however, the function and mechanism of action remain unclear. In this study, we constructed the Mce2D knockout strain using Mycobacterium smegmatis to study the function of Mce2D in the infection of macrophages. The results indicated that compared to the knockout strain, the release of proinflammatory cytokines (TNF-α and IL-1ß) reduced when WT strain infected the macrophages. Moreover, Mce2D boosted the metabolism of oxidized fatty acids, increased the energy supply of TCA, and lowered the glycolysis of glucose in macrophages after bacterial infection, all of which prevented the polarization of macrophages to M1, which was driven by the fact that Mce2D blocked ERK2 phosphorylation by interacting with ERK2 through its DEF motif. This, in turn, promoted nuclear translocation of HIF-1α, allowing signal accumulation, which increased the HIF-1α transcription levels. Finally, the mouse infection experiment showed that Mce2D caused blockage of M1 polarization of alveolar macrophages, resulting in reduced bactericidal activity and antigen presentation, weakening Th1 cell-mediated immune response and helping bacteria escape the immune system. Our results reveal that Mce2D causes immune escape by blocking M1 polarization in macrophages, providing potential targets for the rational design of therapies against M. tb infection.

Point-of-Care Platform Based on Solid-Phase Fluorescence Filter Effect for Urinary Iodine Testing in Children and Pregnant Women.

Iodine is an essential element that is used to make thyroid hormones. However, people usually ignore their iodine nutrition level, thus leading to a series of thyroid diseases, particularly in areas where medical resources are scarce. Thus, development of a portable, economical, and simple method for the detection of urinary iodine is of significant importance. Herein, a solid-phase fluorescence filter effect (SPFFE) induced by iodine was used to develop an SPFFE-based point-of-care testing (POCT) platform for the detection of urinary iodine by coupling with headspace sample introduction. This method can not only alleviate the matrix interference that occurred in the conventional inner filter effect (IFE) but also achieve high sensitivity. Furthermore, the urinary iodine (UI) POCT platform was developed through the integration of a sample pretreatment and fluorescence readout. This whole system costs less than US $20 and provides accurate temperature control and a portable fluorescence reading within 15-20 min. Compared to the traditional IFE-based assay, the SPFFE-based POCT platform allows the selective detection of iodine as low as 10 nM and has a linear range of 0.05-4 µM. In addition, it provides notable visualization from blue-violet to orange-red in the presence of iodine, which tends to indicate the iodine nutritional status of the human body. Eventually, the clinical applicability and feasibility of the UIPOCT platform as an early diagnostic test kit were confirmed by determining the iodine in urine samples from children and pregnant women.

Vinylene-Linked Emissive Covalent Organic Frameworks for White-Light-Emitting Diodes.

Covalent organic frameworks (COFs) have gained considerable attention due to their highly conjugated π-skeletons, rendering them promising candidates for the design of light-emitting materials. In this study, we present two vinylene-linked COFs, namely, VL-COF-1 and VL-COF-2, which were synthesized through the Knoevenagel condensation of 2,4,6-trimethyl-1,3,5-triazine with terephthalaldehyde or 4,4'-biphenyldicarboxaldehyde. Both VL-COF-1 and VL-COF-2 exhibited excellent chemical and thermal stability. The presence of vinylene linkages between the constituent building blocks in these COFs resulted in broad excitation and emission properties. Remarkably, the designed VL-COFs demonstrated bright emission, fast fluorescence decay, and high stability, making them highly attractive for optoelectronic applications. To assess the potential of these VL-COFs in practical devices, we fabricated white-light-emitting diodes (WLEDs) coated with VL-COF-1 and VL-COF-2. Notably, the WLEDs coated with VL-COF-1 achieved high-quality white light emission, closely approximating standard white light. The promising performance of VL-COF-coated WLEDs suggests the feasibility of utilizing COF materials for stable and efficient lighting applications.

Paper-assisted ratiometric fluorescent sensors for on-site sensing of sulfide based on the target-induced inner filter effect.

Dissolved sulfide tends to species transformation and loss upon leaving the matrix, thus the development of a practical on-site determination of sulfide is crucial for environmental monitoring and human health. In this work, a novel paper-based ratiometric fluorescence sensor was developed for the field analysis of sulfide, which system was constructed by the inner filter effect (IFE) of CdS quantum dots (QDs) toward carbon dots (C-dots). Instead of an aqueous phase system, the conversion of sulfide to its hydride would induce the in-situ formation of CdS QDs on the paper, which acted as an energy acceptor to quench the emission of C-dots, leading to a variation of ratiometric fluorescence from blue to yellow with the increasing concentration of sulfide. Moreover, we proposed a smartphone-based fluorescence capture device integrated with a programmed Python program, accomplishing both color recognition and accurate detection of sulfide. Under the optimal condition, this ratiometric fluorescence sensor allowed for the on-site analysis of sulfide with a limit of detection of 0.05 µM. The accuracy of the sensor was validated via the successful field analysis of environmental water samples with satisfactory recoveries. Compared to other fluorescence methods used for sulfide analysis, this developed system retains the advantages of label-free, low-cost, ease of operation, and miniaturization, showing great potential for the measurement of sulfide on-site, as well as environmental monitoring.