A sensitive ratiometric fluorescence probe with a large spectral shift for sensing and imaging of palladium.

Palladium (Pd) is an important heavy metal with excellent catalytic properties and widely used in organic chemistry and the pharmaceutical industry. Efficient and convenient analytical techniques for Pd are urgently needed due to the hazardous effects of Pd on the environment and human health. Herein, we have developed five new ratiometric probes for the selective detection of Pd0 based on the Pd-catalyzed Tsuji-Trost reaction. Among them, the F-substituted probe PF-Pd showed the largest spectral shift (148 nm) and the most sensitive response (detection limit 2.11 nM). PF-Pd was employed to determine Pd0 in tap water or lake water samples, which presented satisfactory accuracy and precision. In addition, profiting from its distinct colorimetric response, visual detection of Pd0 was performed on PF-Pd loaded test strips or in field soil samples. Furthermore, fluorescence imaging of living 4T1 cells demonstrated that PF-Pd is suitable for imaging of intracellular Pd0. The good analytical performance of PF-Pd may enable it to be widely used in the convenient, rapid, sensitive and selective detection of Pd0 in environmental or biological analysis.

A simple and sensitive electrochemical sensor for the detection of peptidase activity.

In this work, a simple and sensitive electrochemical sensor was proposed for the detection of ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity. Firstly, the BACE1 specific peptide was modified onto the Au electrode to graft a single-strand DNA with polycytosine DNA sequence (dC12) via amide bonding between peptide and dC12. Because the dC12 is abundant in phosphate groups, thus it can react with molybdate to form redox molybdophosphate, which can generate electrochemical current. Using BACE1 as a model peptidase, the proposed sensor shows a linear response range from 1 to 15 U/mL and limit of detection down to 0.05 U/mL. The sensor displays good performance for the BACE1 activity detection in human serum samples, which may have potential applications in the clinical diagnostics of Alzheimer's disease.

A "signal-on" photoelectrochemical sensor for human epidermal growth factor receptor 2 detection based on Y6/CdS organic-inorganic heterojunction.

A "signal-on" photoelectrochemical (PEC) immunosensor was successfully constructed for determination of human epidermal growth factor receptor 2 (HER2) based on organic-inorganic heterojunction Y6/CdS as photoactive material. Compared with single organic semiconductor, Y6, Y6/CdS exhibited higher photoelectric conversion efficiency due to the formation of heterojunction. In the presence of HER2, sandwich immune structure was formed between HER2 aptamer and anti-HER2 antibody (Ab) by specific recognition. The polydopamine (PDA) nanoparticles were used for signal amplification to enhance photocurrent intensity as PDA can act as electron donor to eliminate holes and promote electron-hole pairs separation. The developed PEC sensor displayed a wide detection range of 5-1000 pg mL-1 and a low detection limit of 2.2 pg mL-1 for HER2 (S/N = 3). The sensor was successfully used for the detection of HER2 in serum with recoveries between 94.8 and 104% and relative standard deviations (RSDs) in the range of 1.2-4.3%. Furthermore, the designed immunosensor possessed good stability, selectivity, and reproducibility, which can find potential clinical applications for disease diagnosis. A "signal-on" photoelectrochemical sensor was reported for human epidermal growth factor receptor 2 detection based on Y6/CdS organic-inorganic heterojunction.

Photoelectrochemical assay for the detection of circulating tumor cells based on aptamer-Ag2S nanocrystals for signal amplification.

In this work, we developed a photoelectrochemical assay for circulating tumor cells (CTCs) detection based on hexagonal carbon-nitrogen tubes (HCNT) as visible light-sensitive materials. The MCF-7 cell was selected as the model CTC and was captured through specific recognition between epithelial cell adhesion molecules (EpCAM) on the cell surface and anti-EpCAM antibodies. Anti-EpCAM antibody-modified magnetic nanoparticles were used to enrich and separate MCF-7 cells from samples. The detection signal was amplified by Ag2S nanocrystals, which can compete with HCNTs for absorbing visible light, leading to a decrease of photocurrent intensity. The linear range of the assay for MCF-7 cells is from 10 to 5000 cells mL-1, with a detection limit of 3 cells mL-1 (S/D = 3). The assay has good selectivity for MCF-7 detection over HeLa cells. The assay was successfully applied for the detection of MCF-7 in human whole blood, which indicates the potential for clinical application.

Gold nanocluster-europium(III) ratiometric fluorescence assay for dipicolinic acid.

A ratiometric fluorescence assay was designed for determination of dipicolinic acid (DPA), a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis. The dual-channel fluorescence probe integrates two fluorescent materials, Eu3+ ion and gold nanocluster (Au NC). The Au NC is used as a reference channel to measure background noise and the Eu3+ ion as the DPA-specific response signal channel. The probe was prepared through simply combing bovine serum albumin (BSA)-scaffolded Eu3+ ion and Au NCs. When excited at 530 nm, in the presence of DPA, the fluorescence signals of Eu3+ ion at 595, 617, and 695 nm increased significantly while the 650 nm signal of Au NC reference remained relatively constant. This fluorescence probe has good photo-stability and also displays good selectivity and high sensitivity for DPA with a low detection limit of 0.8 µM. The linear range of the ratiometric probe for DPA is 1-50 µM. For determination of DPA released during the germination of Bacillus subtilis spores, the detection results were in agreement with measurements by conventional calorimetry assay. The method may have potential for measuring the level of contamination and germination by spores. Graphical Abstract Dual-channel fluorescence biosensor was designed to detect dipicolinic acid, a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis.

Photoelectrochemical detection of human epidermal growth factor receptor 2 (HER2) based on Co3O4-ascorbic acid oxidase as multiple signal amplifier.

A sensitive photoelectrochemical (PEC) sensor based on hexagonal carbon nitride tubes (HCNT) as photoactive material was prepared for the detection of human epidermal growth factor receptor 2 (HER2). Magnetic Fe3O4 nanospheres (MNs) modified with anti-HER2 antibodies were employed for highly efficient capture of HER2 from serum sample, and Co3O4 nanoparticles (Co3O4 NPs) modified with ascorbic acid oxidase (AAO) as well as HER2 aptamer were used for signal amplification. When the aptamer-Co3O4-AAO probe was captured onto the electrode surface through the specific binding of the aptamer with HER2, the photocurrent intensity decreased. This was because Co3O4 NPs competed with HCNT for consumption of the excitation energy. As a consequence AAO catalyzed the oxidation of the electron donor (AA), and the aptamer-Co3O4-AAO probe increased the steric hindrance at the electrode surface, leading to significant photocurrent intensity decrease, thus realizing multiple signal amplification. Based on this signal amplification strategy, at 0 V (vs Ag/AgCl), the PEC sensor shows a wide linear response ranging from 1 pg mL-1 to 1 ng mL-1 with a low detection limit of 0.026 pg mL-1 for HER2. Importantly, the prepared PEC sensor was applied for detection of HER2 in human serum samples with recoveries between 98.8 and 101%. Sensitive photoelectrochemical sensor based on Co3O4 nanoparticles modified with ascorbic acid oxidase for signal amplification is reported.

In Situ Incorporation of Fluorophores in Zeolitic Imidazolate Framework-8 (ZIF-8) for Ratio-Dependent Detecting a Biomarker of Anthrax Spores.

Monitoring and early warning of spores germination is of great significance in avoiding their potential pathogenicity. Thus, effective monitoring of markers during spore germination is of great value. A ratio-dependent fluorescent probe based on in situ incorporation of fluorophores in a metal-organic framework (MOF) was designed to monitor a main component of bacterial spores, 2,6-pyridinedicarboxylic acid (DPA), with high sensitivity and specificity. The fluorescence of CdS quantum dots loaded on zeolitic imidazolate framework-8 (ZIF-8) nanocrystals is initially quenched by europium ions. The europium ions, however, can be seized by DPA, leading to restoring the fluorescence of quantum dots. Simultaneously, the fluorescence of another dye molecule, rhodamine 6G, loaded on the ZIF-8 is not affected by DPA and can serve as a stable internal fluorescence reference signal. On this basis, a ratio-dependent fluorescence method for rapid detection of DPA was established. The linear calibration ranged from 0.1 to 150 µM with a detection limit of 67 nM, which is much lower than the amount of DPA (60 µM) released by the contagious number of spores needed to cause anthrax. This analysis platform exhibits good anti-interference ability for monitoring spore germination. The practicable application of the method was verified by monitoring and imaging the release of DPA in the course of spore germination.

Aptamer-based photoelectrochemical assay for the determination of MCF-7.

In this work, an aptamer-based photoelectrochemical (PEC) assay is reported for the determination of MCF-7 breast cancer cells using hexagonal carbon nitride tubes (HCNTs) as photoactive material. The aptamer immobilized on the HCNT surface can specifically bind with mucin 1 protein (MUC1) that is overexpressed on the surface of MCF-7 cell. Thus, the PEC assay has high specificity for the determination of MCF-7. The determination of MCF-7 is due to the binding of MCF-7 onto HCNT that suppressed the photocurrent intensity. The PEC assay displays good performances for MCF-7 determination with a linear range from 1 × 102 to 1 × 105 cell mL-1 and limit of detection down to 17 cells mL-1. Meanwhile, the PEC assay can distinguish MCF-7 from normal cells in blood samples, which may have potential applications in cancer diagnostics and therapeutics.

Gold nanoparticle-modified black phosphorus nanosheets with improved stability for detection of circulating tumor cells.

Gold nanoparticle (AuNP)-anchored BP nanosheets were synthesized through in situ growth of AuNPs onto BP. Due to the strong chelating ability of P or phosphorus oxides with AuNPs, the stability of BP is improved. As proof-of-concept demonstration of the functionalized BP, electrochemical detection of circulating tumor cells (CTCs) based on BP@AuNPs@aptamer as a probe combined with immunomagnetic separation is reported. The aptamer can specifically bind with CTCs, while the phosphorus oxides including phosphite ion and phosphate ion (PxOy species) on BP and aptamer can react with molybdate to generate an electrochemical current, leading to dual signal amplification. The biosensor is applied to MCF-7 cell detection and displays good analytical performance with a detection limit of 2 cell mL-1. Furthermore, the practicality of this biosensor was validated through sensitive determination of MCF-7 cells in human blood. Therefore, the reported biosensor could be applied to detect other biomarkers, offering an ultrasensitive strategy for clinical diagnostics. Graphical abstract Electrochemical detection of circulating tumor cells based on gold nanoparticle-modified black phosphorus nanosheets is reported.

The clinical study of fast-track rehabilitation nursing in the perioperative period of therapeutic laparoscopy of colon cancer patients.

OBJECTIVE: To explore the clinical application of fast-track rehabilitation nursing in the perioperative period of therapeutic laparoscopy of colon cancer patients. METHODS: Patients with colorectal cancers who were hospitalized in the Department of Oncology and General Surgery of The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University from August 2016 to December 2018 were selected as the research subjects of the study. All the research subjects were divided into the study group 1(n=29), the study group 2(n=29) and the control group (n=24). The control group received routine nursing during the perioperative period, and the research group 1 and 2 received rapid rehabilitation nursing during the perioperative period. Postoperative comparison was made between the two groups on the differences in the time of the first time out of bed, the time of the first anal exhaust, and the time of the first feeding. The differences of pain control in each group after nursing care were evaluated by the pain scale, and the degree of satisfaction of each group was evaluated by the satisfaction scale. RESULTS: In terms of the basic information of patients, the experimental results had indicated no significant statistical difference among the study group 1, the study group 2, and the control group (P>0.05). By analysing the postoperative physical condition indicators of patients, the time of first off-bed activity, the time of first anal exhaust, and the first time of food intake of patients in the observation group 1 and the observation group 2 were significantly different (P<0.05) as compared with the control group. Besides that, the postoperative pain scale and pain satisfaction of patients were observed, in which the difference in pain scales at each 6h, 12h, 24h, and 48h after the surgeries were statistically significant (P<0.05). In terms of the satisfaction of pain control or pain relief, the differences were statistically significant (P<0.05). CONCLUSIONS: Therefore, it was concluded that the fast-track rehabilitation nursing could promote the treatment of colon cancer patients. Despite the deficiencies of the experimental processes, the study has provided the good results on fast-track rehabilitation nursing with a reliable theoretical basis.

Photoelectrochemical detection of breast cancer biomarker based on hexagonal carbon nitride tubes.

Photoelectrochemical (PEC) sensor for sensitive detection of breast cancer biomarker human epidermal growth factor receptor 2 (HER2) utilizing hexagonal carbon nitride tubes (HCNT) as photoactive material is reported. The detection is based on suppression of the PEC current intensity of the sensor. HCNT were synthesized via a facile hydrothermal method with large specific surface area and low electron-hole recombination. Au nanoparticles (AuNPs) were deposited onto the surface of the HCNT, which enhanced the photocurrent intensity of the HCNT by one time. For HER2 detection, peptide specific to HER2 was immobilized on the AuNPs surface for capturing HER2 molecules. The following binding of HER2 with HER2 aptamer and the reaction of phosphate groups on aptamer with molybdate can form molybdophosphate precipitate, which sticks to the surface of HCNT and impedes electron transport. Thus, photocurrent intensity of the sensor was suppressed. Under optimal conditions, the linear relationship between the PEC intensity and the logarithm of HER2 concentration was from 0.5 to 1 ng mL-1 with low limit of detection (LOD) of 0.08 pg mL-1. Furthermore, the PEC sensor also displayed capability for detecting HER2 in human serum samples. This PEC sensor signal detection strategy can be easily adapted to other PEC sensors involving DNA and find wide applications. Graphical abstract.

C3N4 nanosheet-supported Prussian Blue nanoparticles as a peroxidase mimic: colorimetric enzymatic determination of lactate.

Prussian Blue nanoparticles were deposited on g-C3N4 nanosheets. The resulting nanocomposite possesses peroxidase-like (POx) activity and can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine at room temperature in the presence of H2O2. This leads to formation of a blue product with an absorption maximum at 650 nm. The formation of the Prussian Blue nanoparticles on the g-C3N4 nanosheets, and the POx-like activity of the composite were characterized in detail. The POx mimic was used for determination of L-lactic acid via detection of H2O2 that is produced by the enzyme lactate oxidase (LOx). The assay has a linear range that extends from 5 to 100 µM, and the detection limit is 2.2 µM. The method was successfully applied to the determination of L-lactic acid in spiked human serum. Graphical abstract Ultra-small Prussian Blue (PB) nanoparticles were used to modify g-C3N4 nanosheets, and their peroxidase-like activity was explored for detection of L-lactic acid. LOx represent L-lactate oxidase, and TMB represents 3,3',5,5'-tetramethylbenzidine.

A porous carbon nitride modified with cobalt phosphide as an efficient visible-light harvesting nanocomposite for photoelectrochemical enzymatic sensing of glucose.

A porous carbon nitride (PCN) modified with cobalt phosphides (CoP) was synthesized. In this nanocomposite, the CoP (in different weight fractions) serves (a) as the electron acceptor to accelerate the photoinduced charge separation, and (b) as the photosensitizer to increase the photoelectrochemical (PEC) response to visible light. Dissolved oxygen acts as the electron acceptor to generate PEC current. If glucose oxidase (GOx) catalyzes the oxidation of glucose, dissolved oxygen is consumed. This leads to the suppression of photocurrent. The photocathode biosensor has a linear response in the 0.05 to 0.7 mM glucose concentration range and a 1.1 µM limit of detection. Graphical abstractSchematic of a photoelectrochemical glucose biosensor based on the use of cobalt phosphide-modified porous carbon nitrides. PCN: porous carbon nitride; CoP: cobalt phosphide.

Porous Ni3N nanosheet array as a catalyst for nonenzymatic amperometric determination of glucose.

A glassy carbon electrode was modified with an array of porous Ni3N nanosheets (Ni3N NA) and studied for its use in non-enzymatic electrochemical detection of glucose. The morphology and structure of the Ni3N NA were characterized by scanning electron microscopy and X-ray diffraction. Electrochemical studies demonstrated that the Ni3N NA acts as an efficient catalyst for the electro-oxidation of glucose at pH 13, best at a working voltage of 0.55 V (vs. Ag/AgCl). Figures of merit include (a) high sensitivity (39 µA·mM-1·cm-2), (b) a low limit of detection (0.48 µM), and (c) a linear range that extends from 2 µM to 7.5 mM. The sensor was applied to the determination of glucose levels in human serum, and satisfactory results were obtained. Graphical abstract Nonenzymatic electrochemical glucose sensor based on porous Ni3N nanosheet array. The arrow indicates the successive addition of glucose standard solutions.

Self-Assembled DNA Generated Electric Current Biosensor for HER2 Analysis.

We have developed a new DNA self-assembly amplification technology that generates electric current for electrochemical biosensing. The new technology was used for detection of human epidermal growth factor receptor 2 (HER2). In our technology, an aptamer was utilized both as a ligand for recognition and as a signal generating reporter. The aptasensor is based on a sandwich format and a DNA primer on a HER2 aptamer initiates auxiliary DNA self-assembled on the electrode to form a long one-dimensional DNA. The resulting DNA is then reacted with molybdate to generate electrochemical current. The sensitivity of the aptasensor with DNA self-assembly was greater than that of the aptasensor without DNA self-assembly due to the extended length of the DNA strand. Aptasensor analysis of HER2 in serum of breast cancer patients and healthy individuals is highly correlated (R2 = 0.9924) with ELISA measurements, with a p value of 1.37 × 10-7. The analysis of HER2 in serum (confirmed by ELISA) suggests that HER2 levels in breast cancer patients are much higher than healthy individuals. For HER2 positive patients, the levels are higher than those of HER2 negative patients. After surgery, there is a drop of HER2 levels in serum, suggesting potential clinical applications of the new self-assembled DNA electric current generating biosensor. Unlike proteins, DNA is easily amplifiable. The DNA signal amplification method presented here enables effective current generation, which can find wide range of biomedical applications for protein detection.

Comprehensive monitoring of mitochondrial viscosity variation during different cell death processes by a NIR mitochondria-targeting fluorescence probe.

Cell death is a fundamental feature of multicellular organisms, in which mitochondria play crucial roles. Therefore, revealing and monitoring the microenvironment of mitochondria are significant to investigate cell death process. Herein, the mitochondrial viscosity variation behaviors of a series of different cell death processes were monitored with a NIR mitochondria-targeting fluorescence probe FLV. FLV was designed based on a rotatable flavylocyanine fluorophore that presented selective and sensitive NIR fluorescence enhancement response with the increase of environmental viscosity. Fluorescence imaging experiments of living cells incubated with nystatin or under different temperature indicated that FLV was capable of imaging the change of mitochondrial viscosity. Finally, FLV was applied for monitoring the mitochondrial viscosity variation during different cell death processes. It was found that there were obvious mitochondrial viscosity increases during apoptosis, necrosis and autophagy; however, no detectable mitochondrial viscosity variation was observed in ferroptosis process incubated with ferroptosis inducer erastin or RSL3 for 6 h. These results demonstrated that FLV is a viable tool for monitoring the mitochondrial viscosity variation and is likely to be used in the diagnosis of the mitochondrial viscosity-associated cell processes and diseases.

The Effect of Reading Leaflets During the Observation Period After Vaccination on Knowledge of COVID-19 and Vaccines Among Chinese Small Town Residents: A Randomized Controlled Trial.

Background: Public health education is essential for epidemic prevention and control in the post-COVID-19 era. This randomized controlled trial (RCT) aims to evaluate the effect of reading leaflets during the observation period after vaccination on knowledge of COVID-19 disease and vaccines in Chinese small town residents and to provide suggestions for public health education. Methods: Residents were recruited during the observation period after getting vaccinated against COVID-19 in Xidian and were randomly divided into an education group and a control group. The education group was asked to complete the questionnaire after reading a leaflet, whereas the control group directly completed the questionnaire. The questionnaire comprised two sections on COVID-19 knowledge and vaccine knowledge, and the scores were used to assess the resident's knowledge. Results: A total of 142 participants in the education group and 154 participants in the control group were enrolled. The rates of correct knowledge in the education group and the control group were 90.7 and 83.1%, respectively. The scores of the two sections and the aggregate knowledge score of the education group were significantly higher than those of the control group (P < 0.001). The rates of correct responses to questions on clinical manifestations and transmission routes of COVID-19 and indications and contraindications of vaccines significantly increased after reading the leaflets (P < 0.05). Knowledge of different groups of genders, ages, marital statuses, education levels and occupations all improved (P < 0.05), and the 18-29-year-old and never-married group revealed a higher growth rate of correct responses. Conclusion: Chinese small town residents have a median level of knowledge regarding COVID-19 disease and vaccines. Reading leaflets during the observation period after vaccination effectively improved their knowledge. This low-cost and efficient health education approach can be widely applied.

Knowledge, Attitudes, and Practices toward COVID-19 and Vaccines among Chinese Small-Town Residents: A Cross-sectional Study.

China has basically controlled the COVID-19 epidemic as a result of widespread vaccination and other containment strategies, despite localized outbreaks, as of September 2021. This study investigates the knowledge, attitudes, and practices (KAP) of COVID-19 and COVID-19 vaccines among Chinese small-town residents to provide suggestions for public health policy. Residents who were vaccinated against COVID-19 were asked to complete a paper questionnaire on KAP in Xidian, Zhejiang. The knowledge questionnaire consisted of 12 questions regarding COVID-19 and 12 questions regarding COVID-19 vaccines. Attitude and practice evaluation included agreement on the eventual control of COVID-19 and having recently worn a mask outside. Of 405 survey responders, 52.3% were male, 71.4% had middle school education or less, and 59.0% engaged in physical labor as an occupation. The correct answer rates of the COVID-19 section and the vaccine section were 79.2% and 71.7%, respectively. Age groups of 18 to 29 years and > 50 years, occupations of physical labor and unemployment, and primary school education and less were associated with lower knowledge scores. The majority of participants (91.6%) believed that COVID-19 will eventually be controlled, whereas women, students, and patients with chronic held relatively negative attitudes toward epidemic control. Most participants (87.4%) wore masks outside recently. In conclusion, Chinese small-town residents have a medium level of knowledge regarding COVID-19 and vaccines, hold positive attitudes, and have appropriate practices. Health education should be provided to the target populations to enrich their knowledge of COVID-19 and vaccines, and to improve their attitudes toward epidemic control.

Liver test abnormalities in asymptomatic and mild COVID-19 patients and their association with viral shedding time.

BACKGROUND: Asymptomatic infections and mild symptoms are common in patients infected with the Omicron variant, and data on liver test abnormalities are rare. AIM: To evaluated the clinical characteristics of asymptomatic and mild coronavirus disease 2019 (COVID-19) patients with abnormal liver test results. METHODS: This retrospective study included 661 laboratory-confirmed asymptomatic and mild COVID-19 patients who were treated in two makeshift hospitals in Ningbo from April 5, 2022 to April 29, 2022. Clinical information and viral shedding time were collected, and univariate and multivariate logistic regression models were performed in statistical analyses. RESULTS: Of the 661 patients, 83 (12.6%) had liver test abnormalities, and 6 (0.9%) had liver injuries. Abnormal liver tests revealed a reliable correlation with a history of liver disease (P < 0.001) and a potential correlation with male sex and obesity (P < 0.05). Elevated alanine aminotransferase was reliably associated with obesity (P < 0.05) and a history of liver disease (P < 0.001). Elevated aspartate transaminase (AST) was reliably correlated with a history of liver disease (P < 0.001), and potentially correlated with age over 30 years (P < 0.05). There was a reliable correlation between AST ≥ 2× the upper limit of normal and a longer viral shedding time, especially in mild cases. CONCLUSION: Obesity and a history of liver disease are risk factors for liver test abnormalities. Being male and an older age are potential risk factors. Attention should be given to liver tests in asymptomatic and mild COVID-19 patients, which has crucial clinical significance for evaluating the viral shedding time.

An "on-off-super on" photoelectrochemical sensor based on quenching by Cu-induced surface exciton trapping and signal amplification of copper sulfide/porous carbon nitride heterojunction.

In this work, we report an "on-off-super on" photoelectrochemical sensor for probing hydrogen sulfide due to its toxicity in water environment by using porous carbon nitride as photoelectric transducers. Synthesized by an alkaline-assisted hydrothermal method, the porous carbon nitride photoanode exhibited a remarkable photocurrent on the initial "on" state. Cu2+ immobilized on the surfaces of porous carbon nitride could significantly decrease the charge transfer efficiency and quench the photoelectrochemical signal in the "off" state. In addition, the introduction of S2- ions could eliminate the influence of Cu-induced surface exciton trapping and amplify the photoelectrochemical signal due to the formation of carbon nitride/copper sulfide heterojunction, thus leading to the achievement of the ''super on'' state and subsequently detection of hydrogen sulfide. More importantly, this photoelectrochemical sensor shows the excellent performance for probing hydrogen sulfide in terms of stability, selectivity, sensitivity and fabrication cost. Enabled by a unique "on-off-super on" strategy, it could serve as a reference for developing the new class of photoelectrochemical sensor.