A ternary CdS@Au-g-C3N4 heterojunction-based photoelectrochemical immunosensor for prostate specific antigen detection using graphene oxide-CuS as tags for signal amplification

Multipath collaboration-based signal amplification on Z-scheme In2O3/g-C3N4 heterojunction photoelectrode for sensitive photoelectrochemical immunoassay

The ideal photoelectrode and efficient signaling strategy are pivotal to achieve sensitive photoelectrochemical (PEC) analysis. Here, a multipath collaborative signal amplification-based PEC immunosensor was constructed for the ultrasensitive detection of cytokeratin 19 fragment 21-1. Specifically, the photoelectrode fabricated by Z-scheme In2O3/g-C3N4 heterojunction showed enhanced photocurrent intensity in response to visible light. Meanwhile, the signal probe, horseradish peroxidase functionalized dopamine-melanin nanosphere@Au nanoparticles (HRP-Dpa-melanin NS@AuNPs), were introduced into the system. When the target exists, the signal probe can induce multiple quenching of the photocurrent due to the competition of light absorption, steric hindrance and HRP-mediated biocatalytic precipitation, which effectively inhibit light, electron donor, and electron access to the photoelectrode. The fabricated immunosensor exhibits a wide linear range from 1.0 × 10-3 - 1.0 × 102 ng mL-1 with the detection limit of 0.35 pg mL-1 (S/N = 3) for cytokeratin 19 fragment 21-1 detection. The study enhances sensitivity for PEC detection by utilizing the superior Z-scheme heterojunction photoelectrode, providing a valuable method that combines multiple signal pathways for a synergistic effect in bioanalysis.

Photoelectrochemical biosensors: Prospects of graphite carbon nitride-based sensors in prostate-specific antigen diagnosis

Prostate cancer (PC) is very common in old age and causes many deaths. Early diagnosis and monitoring of the progress of the disease and the effectiveness of PC treatment are critical. On the other hand, choosing a specific biomarker for PCs is essential. Prostate-specific antigen (PSA) is a specific biomarker secreted in the prostate epithelial cells, which increases in cancer cells. Between all employed sensing mechanism, electrochemical sensors based on nanomaterials have created many hopes. Meanwhile, graphite carbon nitride (g-C3N4) is interested in developing photoelectrochemical sensors due to its large surface area, stability, easy modification, and good photoelectronic properties. In this review, electrochemical sensors based on nanocomposites containing g-C3N4 have been investigated in PSA detection. After providing an overview of the characteristics of g-C3N4 and cancer biomarkers, it reviews the strategies and mechanisms involved in identifying PSA. Different approaches to photoelectrochemistry, impedimetric immunosensors, photocatalysis, and luminescence have been used in diagnostic mechanisms. Then, challenges and prospects for electrochemical sensors based on nanocomposites containing g-C3N4 in PSA detection have been analyzed. The recent review generally opens an efficient view in PSA diagnosis and the application of g-C3N4-based electrochemical sensors in personalized medicine diagnosis and treatment.

Can nanotechnology and genomics innovations trigger agricultural revolution and sustainable development?

At the dawn of new millennium, policy makers and researchers focused on sustainable agricultural growth, aiming for food security and enhanced food quality. Several emerging scientific innovations hold the promise to meet the future challenges. Nanotechnology presents a promising avenue to tackle the diverse challenges in agriculture. By leveraging nanomaterials, including nano fertilizers, pesticides, and sensors, it provides targeted delivery methods, enhancing efficacy in both crop production and protection. This integration of nanotechnology with agriculture introduces innovations like disease diagnostics, improved nutrient uptake in plants, and advanced delivery systems for agrochemicals. These precision-based approaches not only optimize resource utilization but also reduce environmental impact, aligning well with sustainability objectives. Concurrently, genetic innovations, including genome editing and advanced breeding techniques, enable the development of crops with improved yield, resilience, and nutritional content. The emergence of precision gene-editing technologies, exemplified by CRISPR/Cas9, can transform the realm of genetic modification and enabled precise manipulation of plant genomes while avoiding the incorporation of external DNAs. Integration of nanotechnology and genetic innovations in agriculture presents a transformative approach. Leveraging nanoparticles for targeted genetic modifications, nanosensors for early plant health monitoring, and precision nanomaterials for controlled delivery of inputs offers a sustainable pathway towards enhanced crop productivity, resource efficiency, and food safety throughout the agricultural lifecycle. This comprehensive review outlines the pivotal role of nanotechnology in precision agriculture, emphasizing soil health improvement, stress resilience against biotic and abiotic factors, environmental sustainability, and genetic engineering.

Dual-mode biosensor using Tb-Cu MOF@Au nanoenzyme to effectively quench the photocurrent of Bi2O3/Bi2S3/AgBiS2 heterojunction and emit fluorescence for neuron-specific enolases detection

A novel dual-mode biosensor was constructed for the ultrasensitive detection of neuron-specific enolase (NSE), utilizing Tb-Cu MOF@Au nanozyme as the signal label to effectively quench the photoelectrochemical (PEC) signals of Bi2O3/Bi2S3/AgBiS2 composites and initiate fluorescent (FL) signals. First, Bi2O3/Bi2S3/AgBiS2 heterojunction with excellent photoelectric activity was selected as the substrate material to provide a stable photocurrent. The well-matched energy levels significantly enhanced the separation and transfer of photogenerated carriers. Second, a strategy of consuming ascorbic acid (AA) by Tb-Cu MOF@Au nanozyme was introduced to improve the sensitivity of the PEC/FL biosensor. Tb-Cu MOF@Au not only could catalyze the oxidation of AA, but the steric effect further reduced the contact of AA with the substrate. More importantly, in the presence of H2O2, a significant fluorescence was produced from Tb3+ sensitized by the oxidation products of AA. Based on the above strategies, a highly stable and sensitive dual-mode biosensor was proposed for accurate NSE determination. Third, the developed dual-mode biosensor demonstrated excellent performance in detecting NSE. In this study, the PEC method demonstrated a wide detection range from 0.00005 to 200 ng/mL with a low detection limit of 20 fg/mL. The FL method exhibited a linear range from 0.001 to 200 ng/mL with a detection limit of 0.65 pg/mL. The designed biosensor showed potential practical implications in the accurate detection of disease markers.

Ternary electrochemiluminescence quenching effects of CuFe2O4@PDA-MB towards self-enhanced Ru(dcbpy)32+ functionalized 2D metal-organic layer and application in carcinoembryonic antigen immunosensing

BACKGROUND

Carcinoembryonic antigen (CEA) is a significant glycosylated protein, and the unusual expression of CEA in human serum is used as a tumor marker in the clinical diagnosis of many cancers. Although scientists have reported many ways to detect CEA in recent years, such as electrochemistry, photoelectrochemistry, and fluorescence, their operation is complex and sensitivity is average. Therefore, finding a convenient method to accurately detect CEA is significance for the prevention of malignant tumors. With high sensitivity, quick reaction, and low background, electrochemiluminescence (ECL) has emerged as an essential method for the detection of tumor markers in blood.

RESULTS

In this work, a "signal on-off" ECL immunosensor for sensitive analysis of CEA ground on the ternary extinction effects of CuFe2O4@PDA-MB towards a self-enhanced Ru(dcbpy)32+ functionalized metal-organic layer [(Hf)MOL-Ru-PEI-Pd] was prepared. The high ECL efficiency of (Hf)MOL-Ru-PEI-Pd originated from the dual intramolecular self-catalysis, including intramolecular co-reaction between polyethylenimine (PEI) and Ru(dcbpy)32+. At the same time, loading Pd NPs onto (Hf)MOL-Ru-PEI could not only improve the electron transfer ability of (Hf)MOL-Ru-PEI, but also provide more active sites for the reaction of Ru(dcbpy)32+ and PEI. In the presence of CEA, CuFe2O4@PDA-MB-Ab2 efficiently quenches the excited states of (Hf)MOL-Ru-PEI-Pd by PDA, Cu2+, and methylene blue (MB) via energy and electron transfer, leading to an ECL signal decrease. Under optimal conditions, the proposed CEA sensing strategy showed satisfactory properties ranging from 0.1 pg mL-1 to 100 ng mL-1 with a detection limit of 20 fg mL-1.

SIGNIFICANCE

The (Hf)MOL-Ru-PEI-Pd and CuFe2O4@PDA-MB were prepared in this work might open up innovative directions to synthesize luminescence-functionalized MOLs and effective quencher. Besides, the ECL quenching mechanism of Ru(dcbpy)32+ by MB was successfully explained by the inner filter effect (ECL-IFE). At last, the proposed immunosensor exhibits excellent repeatability, stability, and selectivity, and may provide an attractive way for CEA and other disease markers determination.

SERS-Temperature Dual-Mode T-type Lateral Flow Strip for Accurate Detection of Free and Total Prostate-Specific Antigens in Blood

Accurate point-of-care (POC) analysis of cancer markers is the essence in the comprehensive early screening and treatment of cancer. Dual-mode synchronous detection is one of the effective approaches to reduce the probability of false negatives or false positives. As a result, this can greatly improve the accuracy of diagnosis. In this work, a surface-enhanced Raman scattering (SERS)-temperature dual-mode T-type lateral flow strip was fabricated to direct and simultaneous POC detection of total and free prostate-specific antigens (t-PSA and f-PSA) in blood. With the advantage of high stability of T-type lateral flow strip and simultaneous acquirement of assay results for t-PSA and f:t PSA ratio, the proposed method has high accuracy in the diagnosis of prostate cancer, especially in the diagnostic gray zone between 4.0 and 10.0 ng/mL. The SERS-temperature dual-signal has a good linear correlation with either f-PSA or t-PSA. To evaluate the clinical diagnostic performance of the proposed method, spiked human serum samples and the whole blood sample were analyzed. The assay results showed good recovery, and compared with traditional electrochemiluminescence immunoassay (ECLIA) method (t-PSA: 43.151; f/t ratio: 0.08), the results obtained by the proposed method were similar (t-PSA: 40.15 (SERS), 36.21 (temperature); f/t ratio: 0.08 (SERS), 0.08 (temperature), but the detection time (15 min) and cost ($0.05) had been greatly reduced. Therefore, the proposed SERS-temperature synchronous dual-mode T-type lateral flow strip has a strong application potential in the field of accurate large-scale diagnostics of prostate cancer on-site by simultaneous POC detection of t-PSA and f-PSA in blood.

Plasmonic-driven charge separation through combining Ag nanoparticles (Ag NPs) to form a double Z-scheme heterostructure in WO3/BiOCl/g-C3N4 for the photocatalytic degradation of antibiotics

Integrating a heterojunction system with the impact of surface plasmon resonance (SPR) is an executable and innovative tactic for photocatalyst amelioration. Ag nanoparticle (Ag NP)-modified WO3/BiOCl/g-C3N4 (WB-CN) was favorably fabricated through in situ photo deposition assembly to form double heterojunctions (A-WBCN). The degradation performance of A-WBCN is better than that of pure g-C3N4 (CN) and WO3/BiOCl (WB), it can degrade more than 90% of OFLX within 20 minutes, due to Ag NPs performing as a bridge for electron mediators, apart from the implications of SPR in A-WBCN. The results of UV diffuse reflectance spectroscopy indicate that loading with Ag NPs can expand the light absorption range of WB-CN to near-infrared. The photoluminescence spectra and transient photocurrent spectra indicate that Ag NP loading significantly improves the separation efficiency of photogenerated carriers. Density functional theory (DFT) simulation results show that the introduction of Ag NPs can change the direction of carrier movement, resulting in bending of the energy bands of WB and CN, improving the redox ability of A-WBCN, and improving its photocatalytic efficiency. In addition, the intermediate products of OFLX was determined by HPLC-MS analysis. The spin electron resonance (ESR) results indicate that ˙O2- and ˙OH are the main active species in photocatalytic degradation. This work furnishes a fresh idea for upgrading photocatalytic performance and advancing electron transfer.

A photoelectrochemical immunosensing platform for ultrasensitive detection of alpha-fetoprotein based on a signal amplification strategy

For the first time, a PEC immunosensor based on a signal amplification strategy is successfully constructed to quantitatively detect alpha-fetoprotein in serum sample. Three favorable factors explain the ultra-high sensitivity of this method. Firstly, compared with pure BiPO₄, the BiPO₄/BiOBr heterojunction has a narrower band gap, which expands the light absorption range and enables the light energy to be fully utilized. Secondly, the separation of photogenerated electrons and hole pairs during PEC detection is due to the efficient matching of energy levels among BiPO₄, BiOBr and CdS, inhibiting the recombination of photogenerated electrons, which improves the performance of PEC immunosensor. Thirdly, due to the presence of CdS, the light absorption capability of the sensor is enhanced, more electron-hole pairs are generated, and the photocurrent signal is increase. Under the optimal conditions, the PEC immunosensor shows a wide linear range of 0.001-1000 ng/mL for AFP and a low detection limit of 0.82 pg/mL. The PEC immunosensor developed in this experiment has excellent reproducibility, stability and high sensitivity, and also achieves satisfactory results in the analysis of human serum samples, establishing a new analytical method for biomarker detection.

2D carbon materials based photoelectrochemical biosensors for detection of cancer antigens

Cancer is a leading cause of death globally and early diagnosis is of paramount importance for identifying appropriate treatment pathways to improve cancer patient survival. However, conventional methods for cancer detection such as biopsy, CT scan, magnetic resonance imaging, endoscopy, X-ray and ultrasound are limited and not efficient for early cancer detection. Advancements in molecular technology have enabled the identification of various cancer biomarkers for diagnosis and prognosis of the deadly disease. The detection of these biomarkers can be done by biosensors. Biosensors are less time consuming compared to conventional methods and has the potential to detect cancer at an earlier stage. Compared to conventional biosensors, photoelectrochemical (PEC) biosensors have improved selectivity and sensitivity and is a suitable tool for detecting cancer agents. Recently, 2D carbon materials have gained interest as a PEC sensing platform due to their high surface area and ease of surface modifications for improved electrical transfer and attachment of biorecognition elements. This review will focus on the development of 2D carbon nanomaterials as electrode platform in PEC biosensors for the detection of cancer biomarkers. The working principles, biorecognition strategies and key parameters that influence the performance of the biosensors will be critically discussed. In addition, the potential application of PEC biosensor in clinical settings will also be explored, providing insights into the future perspective and challenges of exploiting PEC biosensors for cancer diagnosis.

Potential of nanobiosensor in sustainable agriculture: the state-of-art

A rapid surge in world population leads to an increase in worldwide demand for agricultural products. Nanotechnology and its applications in agriculture have appeared as a boon to civilization with enormous potential in transforming conventional farming practices into redefined farming activities. Low-cost portable nanobiosensors are the most effective diagnostic tool for the rapid on-site assessment of plant and soil health including plant biotic and abiotic stress level, nutritional status, presence of hazardous chemicals in soil, etc. to maintain proper farming and crop productivity. Nanobiosensors detect physiological signals and convert them into standardized detectable signals. In order to achieve a reliable sensing analysis, nanoparticles can aid in signal amplification and sensor sensitivity by lowering the detection limit. The high selectivity and sensitivity of nanobiosensors enable early detection and management of targeted abnormalities. This study identifies the types of nanobiosensors according to the target application in agriculture sector.

Ultrathin Covalent Organic Framework Nanosheets/Ti3C2Tx-Based Photoelectrochemical Biosensor for Efficient Detection of Prostate-Specific Antigen

Designable and ultrathin covalent organic framework nanosheets (CONs) with good photoelectric activity are promising candidates for the construction of photoelectrochemical (PEC) biosensors for the detection of low-abundance biological substrates. However, achieving highly sensitive PEC properties by using emerging covalent organic framework nanosheets (CONs) remains a great challenge due to the polymeric nature and poor photoelectric activity of CONs. Herein, we report for the first time the preparation of novel composites and their PEC sensing properties by electrostatic self-assembly of ultrathin CONs (called TTPA-CONs) with Ti₃C₂T_x. The prepared TTPA-CONs/Ti₃C₂T_x composites can be used as photocathodes for PEC detection of prostate-specific antigen (PSA) with high sensitivity, low detection limit, and good stability. This work not only expands the application of CONs but also opens new avenues for the development of efficient PEC sensing platforms.

Photoelectrochemical sandwich immunoassay of CYFRA21-1 based on In2O3/WO3 type-II heterojunction and CdS quantum dots-polydopamine nanospheres labeling

Using an In₂O₃/WO₃ type-II heterojunction modified fluorine-doped tin oxide (FTO) electrode as the photoanode and CdS quantum dots (QDs)-polydopamine nanospheres (PDA NSs) as the secondary antibody (Ab₂) label, the photoelectrochemistry (PEC) sandwich immunosensing of the lung cancer marker CYFRA21-1 was studied. WO₃ nanoplates were prepared by a hydrothermal method, In₂O₃ nanoporous spheres were prepared by a hydrothermal method followed by calcination, and the In₂O₃/WO₃ type-II heterojunction with high PEC activity was prepared by ultrasonic mixing and cast-coating. PDA NSs with a high surface area can be loaded with abundant Ab₂ molecules and many CdS QDs with an energy level well matched with the heterojunction, so the photocurrent signal can be amplified by the formation of a sandwich immunostructure. Through the simulation experiments of photoelectrode-modified chitosan films of varying thickness, the effective transport distance of photogenerated charges is preliminarily discussed. Under the optimized conditions, the photocurrent was linear with the common logarithm of CYFRA21-1 concentration from 100 fg mL^-1 to 50 ng mL^-1, with a limit of detection of 56 fg mL^-1 (S/N = 3). The immunoassay of CYFRA21-1 in human serum samples gave satisfactory recovery results.

Recent advances in electron manipulation of nanomaterials for photoelectrochemical biosensors

This feature article discusses the recent advances and strategies of building photoelectrochemical (PEC) biosensors from the perspective of regulating the electron transfer of nanomaterials.

Biosensing strategies for diagnosis of prostate specific antigen

Almost from the time of its discovery, the prostate specific antigen (PSA) has been one of the most accurate and most extensively studied indicators of prostate cancer (PC). Because of advancements in biosensing systems and technology, PSA analysis methods have been substantially updated and enhanced as compared to their first instances. With the development of techniques in biosensor technology, the number of PSA biosensors that can be used in the biomedical sector is increasing year by year. Many different recognition elements and transducers have been used in the development of biosensor systems that exhibit high sensitivity, selectivity, and specificity. Here in this review, we provide a current overview of the different approaches to PSA detection.

A label-free photoelectrochemical immunosensor for prostate specific antigen detection based on Ag2S sensitized Ag/AgBr/BiOBr heterojunction by in-situ growth method

Prostate cancer is one of the most common cancers in the world, and its early detection is vital to saving the lives of patients. In this research, a novel label-free photoelectrochemical immunosensor was designed for sensitive detection of prostate specific antigen (PSA). Ag₂S sensitized on Ag/AgBr/BiOBr heterojunction could effectively inhibit photogenic holes recombination and improve photocurrent response and sensitivity. Ascorbic acid was an effective electron donor, which can effectively eliminate photo-generated holes. The photocurrent reduced linearly with the logarithm of PSA concentration ranged from 0.001 to 50 ng·mL^-1 and the limit of detection was 0.25 pg·mL^-1. The designed sensor had the advantages of wide linear range, good stability, high reproducibility, and good selectivity. This study not only provided a method for efficient and sensitive detection of PSA, but also provided valuable reference ideas for the detection of other tumor markers.

Construction of a PCN/Fe2O3/CdS double Z-type heterojunction photocatalyst and its application in the oxidative coupling reaction of benzylamine

In this work, a PCN/Fe2O3/CdS ternary heterojuction photocatalyst was constructed by introducing an appropriate amount of ferric oxide (Fe2O3) and cadmium sulfide (CdS) onto porous carbon nitride (PCN), denoted as PCN/Fe2O3/CdS. In the presence of PCN/Fe2O3/CdS, the turnover frequency value and selectivity of the oxidative coupling reaction of benzylamine were 6740 μmol g-1 h-1 and 99.4%, respectively. The excellent catalytic performance of the PCN/Fe2O3/CdS photocatalyst is attributed to fully exposed active sites due to the porous structure of PCN, improved light utilization efficiency by introduction of Fe2O3 and CdS, and increased mobility of e--h+ pairs by construction of a ternary heterostructure, and was proved by the analysis of its structural and optical properties. According to the substrate scope study and Hammett diagram analysis, the rate determining step of the benzylamine self-coupling reaction photocatalyzed by PCN/Fe2O3/CdS was the condensation of imine and benzylamine into N-benzylidenebenzylamine. The results of the free radical quenching experiment and electron spin resonance tests showed that h+ played a major role in the photoreaction process, followed by ˙O2- and ˙OH. After four photocatalytic reaction cycles, the catalytic performance of the PCN/Fe2O3/CdS heterojunction composite material remained good. Finally, combined with the free radical trapping experiment and energy band structure analysis, a possible double Z-type reaction mechanism was proposed.

Enhanced photoactivity of ZnPc@WS2 heterojunction by CuBi2O4 and its application for photoelectrochemical detection of 5-formyl-2'-deoxycytidine

The endogenous epigenetic marker 5-formylcytosine (5 fC) is introduced by 5-methylcytosine (5 mC) oxidation under action of enzyme oxidation, and plays an important role in many life activities. Since the content of 5 fC in mammalian tissues and cells is very low, it is necessary to exploit a sensitive and specific detection method to further understand the function of 5 fC. In this work, a sensitively and selectively photoelectrochemical (PEC) biosensor was developed for 5-formyl-2'-deoxycytidine (5fdC) detection. CuBi₂O₄/ZnPc@WS₂ was used as photoactive material, where the formed ternary heterojunction structure greatly enhanced the PEC response and increased the detection sensitivity. Positively charged polyethyleneimine (PEI) was employed as 5fdC recognition and capture unit, where the amine group on PEI specifically reacted with aldehyde group of 5fdC to form stable amide bond. 4-Carboxyphenylboronic acid (4-CPBA) was adopted as crosslinker for 5fdC and amino functionalized CuBi₂O₄ based on the covalent interaction between 1,3-diol bond on 5fdC and boric acid structure on 4-CPBA, and the covalent interaction between -COOH on 4-CPBA and -NH₂ on amino functionalized CuBi₂O₄. On the basis of the positive synergistic effect of ZnPc and CuBi₂O₄ on improving the photoelectric performance of WS₂, the separation of photo-generated electron-hole pairs in semiconductors were promoted, and the examination range was expanded from 0.1 to 500 nM, and the detection limit was 0.0483 nM (3σ). Based on the unique covalent reaction between -NH₂ and -CHO, the PEC biosensor has excellent detection sensitivity, and can even separate 5fdC from 5-methylcytosine deoxyribonucleoside and 5-hydroxymethylcytosine deoxyribonucleoside. The effect of antibiotics and heavy metals on the 5fdC content in wheat tissue genome has also been further investigated using this sensor.

Label-free photoelectrochemical immunosensor for aflatoxin B1 detection based on the Z-scheme heterojunction of g-C3N4/Au/WO3

Aflatoxin B1 (AFB1) is the most toxic mycotoxin, is widely found in foods and animal feeds, and can pose a serious threat to our lives. A label-free photoelectrochemical (PEC) immunosensor was fabricated for the sensitive detection of AFB1. A Z-scheme heterojunction of gold nanoparticles (Au NPs) loaded on graphitic carbon nitride sheet and tungsten trioxide sphere composite (g-C₃N₄/Au/WO₃) acted as the highly sensitive platform. The g-C₃N₄/Au/WO₃ is capable, not only of immobilizing antibodies via Au NPs, but also enhancing the separation of electron-hole pairs due to its good energy band matching efficiency. The mechanism of photo-generated electron/hole transfer on g-C₃N₄/Au/WO₃ was explored using scavengers to eliminate active components. On this basis, an electron transfer pathway for the immunosensor was deduced. The PEC immunosensor displayed a linear concentration range from 1.0 pg mL^-1 to 100 ng mL^-1 and a low detection limit of 0.33 pg mL^-1 (S/N = 3) for AFB1. Good reproducibility, stability, and specificity provide a solid foundation for the practical application of this immunosensor.

Application of electrochemical methods for the detection of abiotic stress biomarkers in plants

Abiotic stress is the main cause of low productivity in plants. Therefore, it is important to detect stress and respond to it in a timely manner to avoid irreversible damage to plant productivity and health. The application of traditional methods in agriculture is limited by expensive equipment and cumbersome sample processing. More effective detection methods are urgently needed due to the trace amounts and low stabilities of plant biomarkers. Electrochemical detection methods have the unique advantages of high accuracy, a low detection limit, fast response and easy integration with systems. In this review, the application of three types of electrochemical methods to phytohormone assessment is highlighted including direct electrochemical, immunoelectrochemical, and photoelectrochemical methods. Research on electrochemical methods for detecting abiotic stress biomarkers, including various phytohormones, is also summarized with examples. To date, the detection limit of exogenous plant hormones can reach pg/mL or even lower. Nevertheless, more efforts need to be made to develop a portable instrument for in situ online detection if electrochemical sensors are to be applied to the detection of the endogenous hormones or the physiological state of plants. Additionally, plant-wearable sensors that can be directly attached to or implanted into plants for continuous, noninvasive and real-time monitoring are emphasized. Finally, rational summaries of the considered methods and present challenges and future prospects in the field of abiotic stress detection-based electrochemical biosensors are thoroughly discussed.