A versatile CuCo@PDA nanozyme-based aptamer-mediated lateral flow assay for highly sensitive, on-site and dual-readout detection of Aflatoxin B1.

Mycotoxin contaminations in food and environment seriously harms human health. Constructing sensitive and point-of-test early-warning tools for mycotoxin determination is in high demand. In this study, a CuCo@PDA nanozyme-based aptamer-mediated lateral flow assay (Apt-LFA) has been elaborately designed for on-site and sensitive determination of mycotoxin Aflatoxin B1 (AFB1). Benefiting from the rich functional groups and excellent peroxidase-like activity, the CuCo@PDA with original dark color can be conjugated with the specific recognition probe (i.e., aptamer), generating colorimetric signal on the test lines of Apt-LFA via a competitive sensing strategy. The signal can further be amplified in-situ by catalytic chromogenic reaction. Therefore, a visual and dual-readout detection of AFB1 has been realized. The developed Apt-LFA provides a flexible detection mode for qualitative and quantitative analysis of AFB1 by naked-eyes observation or smartphone readout. The smartphone-based LFA platform shows a reliable and ultrasensitive determination of AFB1 with the limit of detection (LOD) of 2.2 pg/mL. The recoveries in the real samples are in the range of 95.11-113.77% with coefficients of variations less than 9.84%. This study provides a new approach to realize point-of-test and sensitive detection of mycotoxins in food and environment using nanozyme-based Apt-LFAs.

Hollow NiCo@C Nanozyme-Embedded Paper-Based Colorimetric Aptasensor for Highly Sensitive Antibiotic Detection on a Smartphone Platform.

Antibiotic residues in the environment and in foods pose a serious threat to ecosystems and human health. Developing sensitive and on-site detection methods is therefore in high demand. In this work, a portable paper-based colorimetric sensor with a smartphone platform with an ultrahigh sensitivity has been designed for on-site and quantitative analysis of antibiotic residues based on aptamer-regulated nanozyme activity. The developed excellent peroxidase-like nanozymes, carbon-protected NiCo bimetal oxides with a unique hollow nanocage structure (NiCo@C HCs), could effectively catalyze the oxidation of chromogenic substrates by H2O2. Once bound to a specific aptamer, the enzyme-mimicking activity of NiCo@C HCs is obviously inhibited as a result of the masking of active sites but could be restored via the target-aptamer recognition. Herein, the aptamer-modified NiCo@C HCs are embedded on paper pieces to construct paper-based biochips for visual detection. Meanwhile, a smartphone platform is integrated for the signal readout. Using enrofloxacin (ENR) as an analyte model, the proposed paper-based analysis platform shows a reliable and sensitive detection of ENR with an ultralow detection limit of 0.029 ng/mL. The platform also works well in various real samples. This analysis method is facile in design, showing a great application potential for on-site and mass screening of antibiotic residues in the environment and in foods.

Multifunctional MnCo@C yolk-shell nanozymes with smartphone platform for rapid colorimetric analysis of total antioxidant capacity and phenolic compounds.

Accurate on-site analysis of food quality, environmental pollutants, and disease biomarkers is of great significance for safeguarding public health. In this work, based on the novel nanozymes, MnCo oxides@carbon yolk-shell nanocages (MnCo@C NCs), a portable colorimetric sensor with smartphone platform has been developed for rapid, on-site and quantitative analysis of total antioxidant capacity (TAC) and phenolic compounds. The MnCo@C NCs are synthesized via one-step calcination of polydopamine-coated MnCo Prussian blue analogs (MnCo-PBA@PDA). The PDA-derived carbon shell is found to be able to protect the nanocages from collapsing, thus increasing their specific surface areas and porosity. Benefiting from the unique structure and multivalent MnCo bimetallic oxides, the MnCo@C NCs perform outstanding catalytic performance and multiple enzyme-mimicking activities including oxidase, laccase and catalase. Hence, a multifunctional application platform integrated smartphone has been constructed for rapid and sensitive colorimetric detection of three model analytes (i.e., ascorbic acid (AA), 2,4-dichlorophenol (2,4-DP), and epinephrine) with extremely low detection limits of 0.29 µM, 0.76 µM, and 0.70 µM, respectively. This sensor device is successfully applied in TAC analysis in vegetables, fruits, and beverages, as well as epinephrine determination in human serum samples. This work provides new insights into designing multifunctional nanozymes to advance the instant detection technology in the field of food supervision, environment monitoring, and human health.

Single-atom Ru loaded on layered double hydroxide catalyzes peroxymonosulfate for effective E. coli inactivation via a non-radical pathway: Efficiency and mechanism.

The Fenton-like processes are considered to be one of the most promising strategies for inactivating bacteria due to their capacity to produce reactive oxygen species (ROS). Herein, a catalytic system for efficient inactivation of Escherichia coli (E. coli) was developed by anchoring single-atom Ru on layered double hydroxides (LDH). The Ru/NiFe-LDH catalyst showed excellent performance in activating peroxymonosulfate (PMS) to inactivate E. coli. Under the combined action of the ultra-low concentrations of Ru/NiFe-LDH (40 mg/L) and PMS (5 mg/L), 7 log E. coli can be totally inactivated within 90 s. This was attributed to the combined effect of single-atom Ru adsorption to E. coli and the ROS produced in situ. Mechanism studies indicated that the 1O2 with electrophilic properties was the key active species responsible for the rapid inactivation of E. coli. The E. coli inactivation process suggested that the ROS produced first attacked the outer membrane of the cell, then the antioxidant enzymes in the cell were induced, the macromolecule substances were released and mineralized, eventually leading to irreversible cell death. This work firstly loads monoatomic Ru on LDH for bacterial inactivation, providing a feasible method for rapid inactivation of E. coli.

The effects of biochar on antibiotic resistance genes (ARGs) removal during different environmental governance processes: A review.

Antibiotic resistance genes (ARGs) pollution has been considered as one of the most significant emerging environmental and health challenges in the 21st century, many efforts have been paid to control the proliferation and dissemination of ARGs in the environment. Among them, the biochar performs a positive effect in reducing the abundance of ARGs during different environmental governance processes and has shown great application prospects in controlling the ARGs. Although there are increasing studies on employing biochar to control ARGs, there is still a lack of review paper on this hotspot. In this review, firstly, the applications of biochar to control ARGs in different environmental governance processes were summarized. Secondly, the processes and mechanisms of ARGs removal promoted by biochar were proposed and discussed. Then, the effects of biochar properties on ARGs removal were highlighted. Finally, the future prospects and challenges of using biochar to control ARGs were proposed. It is hoped that this review could provide some new guidance for the further research of this field.

A novel electrocatalytic system with high reactive chlorine species utilization capacity to degrade tetracycline in marine aquaculture wastewater.

The problems of high salinity and coexistence of antibiotics in mariculture wastewater pose a great challenge to the traditional wastewater treatment technology. Herein, an electrocatalytic system based on cathodes to sustain reactive chlorine species (RCS) in a high chlorine environment was proposed. The results show that the content of RCS is affected by cathodes. The electrocatalytic system with FeNi/NF as cathode has the largest RCS retention capacity when compared with other cathode systems (carbon felt, nickel foam, copper foam, stainless steel, and nickel-iron foam). This is related to FeNi/NF's higher hydrogen production activity, which inhibits the reduction reaction of RCS. Furthermore, the degradation of tetracycline by the proposed FeNi/NF system maintained long-term effective performance across 20 cycles. Thus, the application of high chlorine resistance electrocatalysis system provides a possibility for practical electrocatalysis treatment of mariculture wastewater.

Enhanced electro-oxidation performance of FeCoLDH to organic pollutants using hydrophilic structure.

Iron-cobalt layered double hydroxides (FeCoLDH) showed superior oxygen evolution reaction (OER) performance, but the sluggish water adsorption and dissociation dynamics restrict its capacity to degrade organic pollutants by electro-oxidation. Herein, enhanced electro-oxidation performance of FeCoLDH with hydrophilic structure was designed and exhibited efficient removal efficiency of tetracycline. Theoretical calculation and characterization results consistently elucidated that the electronic structure of FeCoLDH is optimized by doping phosphorus and depositing copper nanodots (NDs). In addition, the obtained Cu NDs/P-FeCoLDH shows higher degradation ability of tetracycline in all-pH conditions than pristine FeCoLDH. That's because it owns smaller barrier with 0.6 eV to generate hydroxyl radicals (•OH) than pristine FeCoLDH. Furthermore, it can effectively degrade organic pollutants in seawater, river water and pharmaceutical wastewater samples. This work provides novel and rational electrode materials for electro-oxidation system with practical application potential, which could offer new insights into the fundamental understanding of electrochemistry.

Tailoring biochar for persulfate-based environmental catalysis: Impact of biomass feedstocks.

Biochar, a carbonaceous material with engineering potential, has gained attention as an efficient catalyst in persulfate-based advanced oxidation processes (PS-AOPs). Although biomass feedstocks are known as a critical factor for the performance of biochar, the relationship between the catalytic efficiency/mechanism and the types of biomass feedstocks is still unclear. Thus, according to recent advances in experimental and theoretical researches, this paper provides a systematic review of the properties of biochar, and the relationship between catalytic performance in PS-AOPs and biomass feedstocks, where the differences in physicochemical properties (surface properties, pore structure, etc.) and activation path of different sourced biochars, are introduced. In addition, how the tailoring of biochar (such as heteroatomic doping and co-pyrolysis of biomass) affects its activation efficiency and mechanism in PS-AOPs is summarized. Finally, the suitable application scenarios or systems of different sourced biochars, appropriate methods to improve the catalytic performance of different types of biochar and the prospects and challenges for the development of biochar in PS-AOPs are proposed.

Highly efficient catalytic hydrogenation of nitrophenols by sewage sludge derived biochar.

Finding a low cost and effective alternative to noble metal based catalyst has long been concerned in wastewater treatment and organic transformation. This work developed a highly efficient sewage sludge-based catalyst via a simple one-step pyrolysis method, and for the first time, applied it in the catalytic reduction of nitrophenols. Due to the higher content of graphitic nitrogen, abundant defect sites and low electron transfer resistance, sewage sludge derived biochar obtained at 800 °C (SSBC-800) exhibits the best catalytic performance, with the reaction rate of 0.48 min-1 and turnover frequency for 4-nitrophenol calculated to be 1.25 × 10-4 mmol•mg-1 min-1, which is comparable to or even superior than some reported noble metal-based catalyst. Moreover, SSBC-800 showed good recyclability of 90% 4-nitrophenol removal within 8 min after 4 runs, and maintained high catalytic activity in reduction of other substituent nitrophenols, such as 2-nitrophenol (0.54 min-1), 3-nitrophenol (0.61 min-1) and 2,4-dinitrophenol (0.18 min-1), and in real water samples, indicating its practical applicability. The electron paramagnetic resonance spectra and electrochemical characterization demonstrate that SSBC-800 accelerates the dissociation of BH4- to form active hydrogen, which is the main species responsible for 4-nitrophenol reduction, while electron transfer reaction involving the surface bound hydride derived from the intimate contact between BH4- and SSBC-800 plays an important role in this process. This research not only provides a novel valorization pathway for sewage sludge, but also sheds new light on further designing of carbon-based catalyst for nitrophenol reduction.

Exploring the role of Fe species from biochar-iron composites in the removal and long-term immobilization of SeO42- against competing oxyanions.

Carbothermal reduction is a convenient and cost-effective method to produce biochar (BC) supported iron-based nano-particles (INP) for oxyanion contaminants removal. However, considering the possible desorption of the target oxyanion during change of the surrounding environment, the detailed removal mechanisms remain unclear and the long-term efficiency of different INPs cannot be predicted. In this study, different BC/Fe composites were synthesized by controlling the pyrolysis temperatures (500-800 °C). BC/Fe3O4 composite synthesized at 500 °C (BC/Fe500) possessed the strongest surface acidity thus with the best SeO42- removal performance, and BC/Fe0/Fe3O4 composite synthesized at 650 °C (BC/Fe650) possessed the best reducing ability toward SeO42-. Through the co-removal experiments (SeO42- and common competing oxyanions co-existed) and the investigation of Se stability loaded on BC/Fe composites, the removal of SeO42- by BC/Fe500 through highly reversible adsorption could not achieve long-term immobilization of Se, making it an appropriate adsorbent for pre-treatment only, while the efficient reduction of SeO42- to Se0 by BC/Fe650 could largely improve its long-term stability. This study supplies a possible strategy for Se immobilization against common competing oxyanions.

The reduction of nitrobenzene by extracellular electron transfer facilitated by Fe-bearing biochar derived from sewage sludge.

In this work, the incorporation of Fe-bearing sludge-derived biochar greatly enhanced both biotic and abiotic reduction of nitrobenzene (NB) to aniline, which was attributed to the concomitant microbial dissimilatory iron reduction. Biogenic Fe(II) produced by Geobacter sulfurreducens dominated the anaerobic reduction of NB following the pseudo-first-order kinetic. Besides, the increase of pyrolysis temperature from 600 to 900 ℃ to generate biochar resulted in an accelerated removal rate of NB in Geobacter-biochar combined system. The morphology and structural characterization of biochar with G. sulfurreducens confirmed the formation of conductive bacteria-biochar aggregates. Electrochemical measurements suggested the presence of graphitized domains and quinone-like moieties in biochar as redox-active centers, which might play an important role in accelerating electron transfer for microbial dissimilatory iron reduction and NB degradation. This study provides a feasible way of using Fe-bearing sludge as a valuable feedstock for biochar generation and its application with electrochemically active bacteria for the bioremediation of nitroaromatic compounds-polluted wastewater.

Insight into the key factors in fast adsorption of organic pollutants by hierarchical porous biochar.

Low-cost biochar adsorbent owning great potential for environmental remediation faces a bottleneck in application for its unsatisfied adsorption performance. Compared to the efforts on increasing adsorption capacity, improving adsorption speed which is important for treatment efficiency is often neglected. Herein, a hierarchical porous biochar (HPB) derived from shrimp shell was prepared and exhibited good adsorption capacity (Qm>300 mg/g) and fast adsorptive equilibrium (≤10 min) towards three typical aromatic organics, whose adsorption universality was further proved by two-way ANOVA analysis. Whereafter, model analysis demonstrated that, the adsorptive forms (mono- and multi-layers) on HPB depended on whether the contaminant is charged. Compared to the benzene-ring site of organics, the charged site contributed 5.13 times to adsorption promotion in monolayer but -0.49 times in inhibition for multilayers forms. Simultaneously, functional group sites contributed relatively weak (0.023 to 0.342 times only). Following structural control revealed that, hierarchical pore structure of HPB was the key for the fast adsorption speed, and highly graphitic structure was important for the high adsorption capacity. This study aims to provide an advanced biochar adsorbent, not only in adsorption capacity but also in adsorptive speed, and reveal the relationship between the structure and adsorption performance of biochar.

Egg shell biochar-based green catalysts for the removal of organic pollutants by activating persulfate.

The sulfate radical based advanced oxidation processes (SR-AOPs) has shown great potential in environmental remediation. In recent years, metal-free catalysts have attracted great attention due to their properties of low environmental risk and high catalytic activity. Among them, biochar-based catalysts are widely studied for their low cost by using substance existing in nature as raw material. In this work, egg shell derived biochar (ES-biochar), which was prepared by a simple one-pot pyrolysis method, has been proven to be an effective and innovative catalyst to activate persulfate for aqueous organic pollutant degradation. In addition, ES-biochar showed superior performance in the degradation reaction with removal efficiency of more than 90% in 120 min for 2,4-dichlorophenol (2,4-DCP), which was selected as a representative organic pollutant. Further quenching tests and electron spin resonance spectroscopy demonstrated that both free-radicals and non-radicals pathways were involved in this process, and OH dominated in free-radicals process. More importantly, this work not only proposed a novel biochar material as an efficient persulfate activator, but also provided a value-added reuse approach for egg shell in line with the concept of resource recycling and environmental sustainability.

Analysis of reaction pathways and catalytic sites on metal-free porous biochar for persulfate activation process.

To develop a metal-free biochar with high and inherent catalytic activity towards refractory and highly toxic contaminants in advanced oxidation processes, it is necessary to explore its reaction pathways and responsible catalytic sites. Herein, a metal-free biochar derived from corn cob (CCBC) was prepared and used for reaction pathway analysis during peroxydisulfate (PDS) activation. The pyrolysis temperature played an important role for regulating the biochar structure and properties, and CCBC obtained at 800 °C showed the best adsorption capacity and catalytic activity towards five typical organic pollutants, including 2, 4-dichlorophenol, Tetracycline hydrochloride, Ciprofloxacin, Methyl orange and Rhodamine B, due to its richer pore and defect structure. Further treatment of pharmaceutical wastewater demonstrated the good efficiency and potential of this metal-free catalyst for practical application. Radical (58% contribution) and non-radical (42% contribution) pathways were both found in CCBC/PDS system. More importantly, further redox experiments manifested that the carbon framework (defects, sp2-hybrid carbon, etc.) only made a contribution to the free radical pathway, while the ketone group (CO) of CCBC was proved to be mainly responsible for the non-radical pathway, namely the generation of singlet oxygen (1O2).

Removal of Sb(III) by sulfidated nanoscale zerovalent iron: The mechanism and impact of environmental conditions.

Pollution of Sb(III) in water has caused great concern in recent years. Nanoscale zero-valent iron (nZVI) can detoxify Sb(III) polluted water, but the rapid passivation and low adsorption capacity limit its practical application. Hence, this study provides a new and efficient nanotechnology to remove Sb(III) using the sulfidated nanoscale zero-valent iron (S-nZVI). The S-nZVI exhibits higher Sb(III)-removal efficiency than pristine nZVI under both aerobic and anoxic conditions. The adsorption capacity of Sb(III) by optimized S-nZVI (465.1 mg/g) is 6 times as high as that of the pristine nZVI (83.3 mg/g) under aerobic conditions. The results indicate that Sb(III) and Sb(V) can be immobilized on the surface of S-nZVI by forming Fe-S-Sb precipitates. Moreover, characterization results demonstrate that the existence of S2- can not only activate H2O2 to produce hydroxyl radical, but also accelerate the cycle of Fe3+/Fe2+ to improve the efficiency of Fenton reaction. Therefore, S-nZVI can produce more hydroxyl radicals to oxidize Sb (III) to Sb (V) and results in 2.3-fold higher oxidation rate of Sb(III) compared to pristine nZVI. The formed FeS layer on the S-nZVI surface can also improve the release ability of Fe2+ and accelerate the formation of nZVI corrosion products. S-nZVI thus holds great potential to be applied in antimony removal.

Tuning Electron Density Endows Fe1-xCoxP with Exceptional Capability of Electrooxidation of Organic Pollutants.

The good performance of base metal catalysts for the electrooxidation of organic pollutants has attracted great attention. However, base metal phosphides for electrooxidation are seldom studied owing to the sluggish water adsorption and dissociation dynamics, which will hinder the production of the sorbed hydroxyl radicals (M(•OH)) and thus inhibit the electrooxidation of organic pollutants. Herein, we proposed a universal strategy to improve the electrooxidation capability of metal phosphides by modulating the surface electron densities. The electron interactions between cobalt (Co) and phosphorus (P) are modulated after iron doping, resulting in more positively charged Co and more negatively charged P, which can promote the adsorption and activation of water molecules and produce large quantities of M(•OH). Meanwhile, the experimental results show that the iron-modulated Fe0.53Co0.47P nanosheet arrays exhibit higher removal efficiency of tetracycline than the boron-doped diamond and Pt anode at low current intensity. Based on experimental results and density functional theory + U calculations (DFT + U), it is found that Fe0.53Co0.47P has lower barrier (0.45 eV) to form the sorbed hydroxyl radicals (M(•OH)) and higher overpotential to produce O2 than its counterparts, suggesting that Fe0.53Co0.47P can produce more M(•OH) instead of O2. The above results highlighted the feasibility of these base metal phosphides for electrooxidation for advanced water purification.

Ultrathin PtNi nanozyme based self-powered photoelectrochemical aptasensor for ultrasensitive chloramphenicol detection.

Nanozymes have gained increasing attention in the field of biosensing. Rationally designed nanozymes with excellent catalytic activity are accessible to substitute natural enzymes. Herein, a novel self-powered photoelectrochemical (PEC) aptasensor was constructed for ultrasensitive detection of chloramphenicol (CAP) based on ultrathin PtNi nanowires (NWs) as nanozyme and benzene-ring doped g-C3N4 (BR-CN) as the photoactive material. The prepared 1-nm-thick PtNi nanozyme acted as a peroxidase, possessing higher catalytic activity than natural horseradish peroxidase (HRP) and other Pt-based mimic enzymes. Through the biotin-streptavidin specific interaction, streptavidin modified PtNi nanozyme was introduced into the dual-stranded DNA (dsDNA) formed by complementary DNA and biotinylated CAP aptamer. The PtNi nanozyme catalyzed 4-chloro-1-naphthol (4-CN) oxidation to generate insoluble precipitation on the electrode surface, resulting in an obvious photocurrent reduction. In the presence of CAP, the CAP aptamer was released from the electrode due to strong affinity with CAP, causing the decrease of catalytic precipitation and consequently the generation of a high photocurrent signal. On the basis of PtNi nanozyme signal amplification, the developed self-powered PEC aptasensor showed a wide linear range of 0.1 pM-100 nM with an ultralow detection limit of 26 fM for the determination of CAP. This work provides a feasible strategy for the design of high-activity nanozyme and self-powered PEC biosensor to achieve the ultrasensitive detection of target analyte.

Carbon-based magnetic nanocomposite as catalyst for persulfate activation: a critical review.

The activation of persulfate to produce active radicals has been attracting wide attention in environmental remediation fields. Among various catalysts, non-metal carbocatalysts and carbon-based composites have shown attractive prospects given that they are environmental-friendly, highly efficient, abundant, and diverse. In this paper, the use of carbon-based magnetic nanocomposites as catalysts for persulfate activation was reviewed and discussed. The preparation methods of carbon-based magnetic nanocomposites were first briefly summarized. Subsequently, the use of activated carbon, carbon nanotubes, graphene oxide, biochar, and nanodiamond-based magnetic composites to activate persulfate was discussed, respectively. A synergetic effect between carbon materials and magnetic nanoparticles facilitated the activation process because of the increased electron transfer capacity, good dispersity of magnetic nanoparticles, and good repeatability and separability. Both radical and non-radical pathways were detected in the activation processes, but the specific mechanisms were greatly influenced by the components of the catalyst and solution conditions. And fundamental studies were needed to clarify the inner mechanisms of the process. In the end, strategies for enhancing the catalytic performances of carbon-based magnetic nanocomposites were suggested. It is expected that this review will provide some inspirations for developing highly efficient and green catalyst, as well as sulfate radical-based advanced oxidation technology for the remediation water environment.

Enhanced photoelectric conversion efficiency: A novel h-BN based self-powered photoelectrochemical aptasensor for ultrasensitive detection of diazinon.

This work presents a novel hexagonal boron nitride (h-BN) based self-powered photoelectrochemical (PEC) aptasensor for ultrasensitive detection of diazinon (DZN) with excellent photoelectric conversion efficiency. It was the first time that h-BN based materials were applied to PEC aptasensor, in which the construction of Z-scheme heterojunction of h-BN and graphitic carbon nitride (CN) via doping sulfur into h-BN was innovatively proposed. Meanwhile, Au nanoparticles (AuNPs) were utilized for the surface plasmon resonance (SPR) effect and the formation of new recombination centers. The charge transfer mechanism was expounded and verified by the electron spin resonance (ESR) spin-trap technique. The proposed PEC aptasensor for determination of DZN exhibited a wide linear range from 0.01 to 10000 nM and a low detection limit of 6.8 pM with superb selectivity and remarkable stability. Moreover, the constructed PEC aptasensor performed well with excellent recoveries in three different real samples. This work illustrated that PEC aptasensor is a promising alternative to conventional analytical technologies for the detection of DZN and other organophosphorus (OP) pesticides. The designing ideas of the proposed h-BN based material can provide a foothold for the innovative construction of photoactive materials for PEC bioanalysis.

Highly sensitive detection of microcystin-LR under visible light using a self-powered photoelectrochemical aptasensor based on a CoO/Au/g-C3N4 Z-scheme heterojunction.

Based on the unique photoelectrochemical properties of a CoO/Au/g-C3N4 Z-scheme heterojunction, a self-powered photoelectrochemical (PEC) aptasensor was constructed for the detection of microcystin-leucine arginine (MC-LR). Z-scheme heterojunctions can promote the separation of a photo-induced electron-hole pair, and the surface plasmonic resonance (SPR) of Au nanoparticles can significantly enhance the adsorption of visible light. Importantly, MC-LR molecules were captured by aptamers initially immobilized on the modified electrode due to their high affinity, and then oxidized by the photogenerated holes, which caused an amplified photocurrent signal, allowing the quantitative analysis of MC-LR by measuring the photocurrent intensity change. This PEC MC-LR aptasensor showed high sensitivity and selectivity within a wide linear response range from 0.1 pM to 10 nM and a detection limit of 0.01 pM. The application of this sensor in the analysis of lake water samples provided accurate results with a relative standard deviation (RSD) of 2.6%-4.2%.