Current Research Status of Azaspiracids.

The presence and impact of toxins have been detected in various regions worldwide ever since the discovery of azaspiracids (AZAs) in 1995. These toxins have had detrimental effects on marine resource utilization, marine environmental protection, and fishery production. Over the course of more than two decades of research and development, scientists from all over the world have conducted comprehensive studies on the in vivo metabolism, in vitro synthesis methods, pathogenic mechanisms, and toxicology of these toxins. This paper aims to provide a systematic introduction to the discovery, distribution, pathogenic mechanism, in vivo biosynthesis, and in vitro artificial synthesis of AZA toxins. Additionally, it will summarize various detection methods employed over the past 20 years, along with their advantages and disadvantages. This effort will contribute to the future development of rapid detection technologies and the invention of detection devices for AZAs in marine environmental samples.

Antihypertensive effect and mechanism of the traditional recipe of medicine food homology (Buyang Huanwu Decoction) in China: Meta analysis and network pharmacological exploration.

Background: Hypertension has become a part of the lives of many people worldwide. With the development, an increasing number of people have begun to control their hypertension through products of medicine food homology, such as Buyang Huanwu Decoction (BYHWD). However, there has been no objective review of the regulation of hypertension by BYHWD. Methods: As of 9 October 2023, this review made a detailed search of nine databases to look for random controlled trials (RCTs) focused on the use of BYHWD for treating hypertension. This was followed by network pharmacological analysis, and molecular docking assessment using AutoDockTools to explore the mode of action. Results: BYHWD was effective in reducing SBP (MD: 0.767; 95 % CI: 0.629, 0.905; p = 0.000), DBP (MD: 0.427; 95 % CI: 0.292, 0.561; p = 0.000), 24h SBP (MD: 0.665; 95 % CI: 0.368, 0.962; p = 0.000), 24h DBP (MD: 0.547; 95 % CI: 0.318, 0.777; p = 0.000), dSBP (MD: 0.625; 95 % CI: 0.395, 0.855; p = 0.000), dDBP (MD: 0.632; 95 % CI: 0.401, 0.862; p = 0.000), nSBP (MD: 0.859; 95 % CI: 0.340, 1.377; p = 0.001), nDBP (MD: 0.704; 95 % CI: 0.297, 1.112; p = 0.001), pv (MD: 1.311; 95 % CI: 0.363, 2.259; p = 0.007) and NIHSS (MD: 1.149; 95 % CI: 0.100, 2.199; p = 0.032), and elevating CER (OR = 2.848; 95 % CI: 1.388, 5.843; p = 0.004). However, BYHWD did not significantly reduce HCY, and there was no significant difference in the incidence of AE. In terms of the mechanism of action, the main active ingredient of BYHWD is quercetin, and the core targets are AKT1, MMP9, and others. Molecular docking also showed that quercetin mainly interacts with the amino acid residue CYS-28 of MMP2. Second, the KEGG analysis showed that BYHWD mainly act on HIF-1, Apelin, and cGMP-PKG signalling pathways, and GO analysis showed that it related to the apical part of the cell, circulatory system processes, and nuclear receptor activity. Conclusion: BYHWD can lowered blood pressure, reduced plasma viscosity, and restored neurological function with good tolerability, and had no significant effect on HCY levels. This study further demonstrated that quercetin is the main active ingredient of BYHWD that acts via the AKT1 and HIF-1 signalling pathways. These results provide new guidance for people's dietary choices by the general public.

Characterization of an ssDNA ligase and its application in aptamer circularization.

Aptamers are widely used in various biomedical areas as novel molecular recognition elements, however, short single-stranded DNA (ssDNA) or RNA oligonucleotides are easily degraded by nucleases in biological fluids. This problem can be solved by circularizing aptamers with circular ligases. Herein, a moderately thermostable ssDNA ligase was expressed and purified. The purified ligase showed good circularization activity for different length substrates and much higher circularization efficiency than T4 RNA ligase 1. Biochemical characterization revealed that the enzyme showed optimal circularization activity at pH 7.5 and 50 ᵒC. Mn2+ and Mg2+ increased enzyme circularization activity, with Mn2+ having higher activity than Mg2+. The optimal concentrations of Mn2+ and ligase were 1.25-2.5 mM and 0.02 nM, respectively. The kinetic parameters Km, Vmax and Kcat of ssDNA ligase were 1.16 µM, 10.71 µM/min, and 10.7 min-1, respectively. The ssDNA ligase efficiency was nucleotide-dependent, and 5'-G and 3'-T were the most ligase-favored terminal nucleotides. In addition, the affinity and stability of the circular aptamer were determined. The affinity constant (KD) was 4.9 µM, and the stability increased compared to its linear form. Molecular docking results showed that the circular aptamer bound to the target via two hydrogen bonds. This study provides a simple and efficient aptamer circularization modification method for improving aptamer stability and expanding its applications.

FAM111B Acts as an Oncogene in Bladder Cancer.

Bladder cancer (BLCA) is a prevalent malignancy of the urinary system, associated with a high recurrence rate and poor prognosis. FAM111B, which encodes a protein containing a trypsin-like cysteine/serine peptidase domain, has been implicated in the progression of various human cancers; however, its involvement in BLCA remains unclear. In this study, we investigated the expression of FAM111B gene in tumor tissues compared to para-tumor tissues using immunohistochemistry and observed a significantly higher FAM111B gene expression in tumor tissues. Furthermore, analysis of clinical characteristics indicated that the increased FAM111B gene expression correlated with lymphatic metastasis and reduced overall survival. To investigate its functional role, we employed FAM111B-knockdown BLCA cell models and performed cell proliferation, wound-healing, transwell, and flow cytometry assays. The results showed that decreased FAM111B gene expression inhibited proliferation and migration but induced apoptosis in BLCA cells. In vivo experiments further validated that FAM111B knockdown suppressed tumor growth. Overall, our findings suggest that FAM111B acts as an oncogene in BLCA, playing a critical role in tumorigenesis, progression, and metastasis of BLCA. In conclusion, we have demonstrated a strong correlation between the expression of FAM111B gene and the development, progression, and metastasis of bladder cancer (BLCA). Thus, FAM111B is an oncogene associated with BLCA and holds promise as a molecular target for future treatment of this cancer.

Prognostic and immunological significance of an M1 macrophage-related gene signature in osteosarcoma.

As the most abundant infiltrating immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) are pivotal in tumor development and treatment. The present investigation endeavors to explore the potential of M1 macrophage-related genes (MRGs) as biomarkers for assessing risk in individuals with osteosarcoma. RNA-sequence data and clinical data were derived from TCGA and GEO databases. The CIBERSORT method was utilized to discern subtypes of tumor-infiltrating immune cells. Identification of MRGs was achieved through Pearson correlation analysis. A prognostic risk model for MRGs was developed using Cox and LASSO regression analyses. A tripartite gene signature comprising CD37, GABRD, and ARHGAP25 was an independent prognostic indicator and was employed to develop a risk score model. The internal and external validation cohort confirmed the results. The area under the ROC curve (AUC) was determined for survival periods of 1 year, three years, and five years, yielding values of 0.746, 0.839, and 0.850, respectively. The C-index of the risk score was found to be superior to clinicopathological factors. GO/KEGG enrichment showed that the differences between high- and low-risk groups were predominantly associated with immune response pathways. Immune-related analysis related to proportions of immune cells, immune function, and expression levels of immune checkpoint genes all showed differences between the high- and low-risk groups. The qRT-PCR and Western blotting results indicate that CD37 expression was markedly higher in MG63 and U2OS cell lines when compared to normal osteoblast hFOB1.19. In U2OS cell line, GABRD expression levels were significantly upregulated. ARHGAP25 expression levels were elevated in both 143B and U2OS cell lines. In summary, utilizing a macrophage genes signature demonstrates efficacy in predicting both the prognosis and therapy response of OS. Additionally, immune analysis confirms a correlation between the risk score and the tumor microenvironment. Our findings, therefore, provide a cogent account for the disparate prognoses observed among patients and furnish a justification for further inquiry into biomarkers and anti-tumor treatment strategies.

A Rapid and Sensitive Aptamer-Based Biosensor for Amnesic Shellfish Toxin Domoic Acid.

With the incidence of harmful algal blooms (HABs) increasing in recent years, the urgent demand for the detection of domoic acid (DA), an amnesic shellfish toxin mainly produced by red tide algae Pseudonitzschia, has aroused increasing attention. Aptamers, a new molecular recognition element, provide clarity in the monitoring of DA. In this study, aptamers of DA were successfully screened by Capture-SELEX. Through identification and truncation optimization, aptamer C1-d with a high affinity (KD value, 109 nM) and high specificity for DA was obtained. The binding mechanism between DA and the aptamer was explored by molecular docking and molecular dynamics (MD) simulation, revealing the critical sites for DA-aptamer interaction. Meanwhile, a BLI-based aptasensor was constructed by C1-d, which displayed a linear range from 0.625 to 10 µM and a LOD of 13.7 nM. This aptasensor exhibited high specificity, good precision and repeatability, and high recovery rates for real samples; the process of detection could be completed in 7 min. This study is the first to identify and investigate the binding mechanism of DA-aptamer interaction and constructed a BLI-based aptasensor for DA, which lays a theoretical foundation for the detection and prevention of DA.

Programmed Aptamer Screening, Characterization, and Rapid Detection for α-Conotoxin MI.

Conotoxins (CTXs) are a variety of mixed polypeptide toxins, among which α-conotoxin MI (CTX-MI) is the most toxic. Serious toxic symptoms, a lack of counteracting drugs, and cumbersome detection processes have made CTX-MI a hidden danger for humans. One of the obstacles to resolving this problem is the absence of specific recognition elements. Aptamers have shown great advantages in the fields of molecule detection, drug development, etc. In this study, we screened and characterized aptamers for CTX-MI through a programmed process. MBMI-01c, the isolated aptamer, showed great affinity, with an affinity constant (KD) of 0.524 µM, and it formed an antiparallel G-quadruplet (GQ) structure for the specific recognition of CTX-MI. Additionally, an aptasensor based on the biolayer interferometry (BLI) platform was developed and displayed high precision, specificity, and repeatability with a limit of detection (LOD) of 0.26 µM. This aptasensor provides a potential tool for the rapid detection of CTX-MI in 10 min. The aptamer can be further developed for the enrichment, detoxification, and biological studies of CTX-MI. Additionally, the programmed process is applicable to screening and characterizing aptamers for other CTXs.

Proteomic Studies of the Mechanism of Cytotoxicity, Induced by Palytoxin on HaCaT Cells.

Palytoxin (PLTX) is a polyether marine toxin isolated from sea anemones. It is one of the most toxic nonprotein substances, causing many people to be poisoned every year and to die in severe cases. Despite its known impact on Na+,K+-ATPase, much still remains unclear about PLTX's mechanism of action. Here, we tested different concentrations of PLTX on HaCaT cells and studied its distributions in cells, its impact on gene expression, and the associated pathways via proteomics combined with bioinformatics tools. We found that PLTX could cause ferroptosis in HaCaT cells, a new type of programmed cell death, by up-regulating the expression of VDAC3, ACSL4 and NCOA4, which lead to the occurrence of ferroptosis. PLTX also acts on the MAPK pathway, which is related to cell apoptosis, proliferation, division and differentiation. Different from its effect on ferroptosis, PLTX down-regulates the expression of ERK, and, as a result, the expressions of MAPK1, MAP2K1 and MAP2K2 are also lower, affecting cell proliferation. The genes from these two mechanisms showed interactions, but we did not find overlap genes between the two. Both ferroptosis and MAPK pathways can be used as anticancer targets, so PLTX may become an anticancer drug with appropriate modification.

[Computer-aided aptamers screening technologies: a review].

The computer information technology that has penetrated into every aspect of our lives, can not only assist the screening of drugs, but also simulate the effect of drugs. At present, computer-aided technologies have been used to screen aptamers, which play an important role in improving the screening efficiency and screening high affinity binding aptamers. This review summarized the screening methods of aptamers through computer-aided sequence evaluation, structural analysis and molecular docking.

Selection, Characterization, and Optimization of DNA Aptamers against Challenging Marine Biotoxin Gymnodimine-A for Biosensing Application.

Gymnodimines (GYMs), belonging to cyclic imines (CIs), are characterized as fast-acting toxins, and may pose potential risks to human health and the aquaculture industry through the contamination of sea food. The existing detection methods of GYMs have certain defects in practice, such as ethical problems or the requirement of complicated equipment. As novel molecular recognition elements, aptamers have been applied in many areas, including the detection of marine biotoxins. However, GYMs are liposoluble molecules with low molecular weight and limited numbers of chemical groups, which are considered as "challenging" targets for aptamers selection. In this study, Capture-SELEX was used as the main strategy in screening aptamers targeting gymnodimine-A (GYM-A), and an aptamer named G48nop, with the highest KD value of 95.30 nM, was successfully obtained by screening and optimization. G48nop showed high specificity towards GYM-A. Based on this, a novel aptasensor based on biolayer interferometry (BLI) technology was established in detecting GYM-A. This aptasensor showed a detection range from 55 to 1400 nM (linear range from 55 to 875 nM) and a limit of detection (LOD) of 6.21 nM. Spiking experiments in real samples indicated the recovery rate of this aptasensor, ranging from 96.65% to 109.67%. This is the first study to report an aptamer with high affinity and specificity for the challenging marine biotoxin GYM-A, and the new established aptasensor may be used as a reliable and efficient tool for the detection and monitoring of GYMs in the future.

A Novel SELEX Based on Immobilizing Libraries Enables Screening of Saxitoxin Aptamers for BLI Aptasensor Applications.

Saxitoxin (STX) is one of the potent marine biotoxins that has high rate of lethality. However, there are no effective treatments at present, and the existing detection methods need to be further explored because of ethical problems or technical limitations. In this work, oligonucleotide aptamers toward STX were screened based on immobilizing libraries on Immobilized Metal-Chelate (IMC), such as Ni-NTA Sepharose, and the IMC-SELEX was conducted by the G-quadruplex library and the random library, respectively. Aptamer 45e (from the G-quadruplex library) and aptamer 75a were obtained after optimization, and aptamer 45e turned out to have a higher affinity toward STX. Furthermore, it was found that the hydrogen bonding and the van der Waals forces (VDW) played major roles in the high efficiency and specificity between STX and 45e by means of molecular docking and dynamics simulation. Based on this, aptamer 45e-1 with the Kd value of 19 nM was obtained by further optimization, which was then used to construct a simple, label-free and real-time optical BLI aptasensor for the detection of STX. This aptasensor showed good reproducibility and stability. In summary, with the advantages of screening aptamers of high efficiency and specificity toward the targets, the proposed IMC-SELEX provides a promising screening strategy for discovering aptamers, which could be used as the potential molecular recognition elements in the fields of biomedicine, food safety and environmental monitoring.

Selection and application of aptamers with high-affinity and high-specificity against dinophysistoxin-1.

Diarrhetic shellfish toxins (DSTs) are marine toxins distributed widely in the world, which pose a major threat to the health of mankind. Dinophysistoxin-1 (DTX-1) has the most potent toxicity in DSTs. However, the current detection methods have ethical problems and technical defects. Further research is needed, to develop a more suitable alternative to the supervision system. In this work, we successfully obtained an aptamer with high affinity and specificity bound to DTX-1 for the first time. After optimization, a core sequence of the aptamer with a higher K D of 64 nM was obtained, while the binding mode of the core sequence and DTX-1 was explored. Based on this aptamer, we developed a biolayer interferometry (BLI) biosensor platform for DTX-1 detection. The aptasensor exhibited a broad detection range from 40 to 600 nM DTX-1 (linear range from 80 to 200 nM), and the low detection limit was 614 pM. Morever, the aptasensor showed good reproducibility and stability, which indicated that this novel aptasensor had broad development prospects for the sensitive and rapid detection of DTX-1.

Measurement of Organ-Specific and Acute-Phase Blood Protein Levels in Early Lyme Disease.

Lyme disease results from infection of humans with the spirochete Borrelia burgdorferi. The first and most common clinical manifestation is the circular, inflamed skin lesion referred to as erythema migrans; later manifestations result from infections of other body sites. Laboratory diagnosis of Lyme disease can be challenging in patients with erythema migrans because of the time delay in the development of specific diagnostic antibodies against Borrelia. Reliable blood biomarkers for the early diagnosis of Lyme disease in patients with erythema migrans are needed. Here, we performed selected reaction monitoring, a targeted mass spectrometry-based approach, to measure selected proteins that (1) are known to be predominantly expressed in one organ (i.e., organ-specific blood proteins) and whose blood concentrations may change as a result of Lyme disease, or (2) are involved in acute immune responses. In a longitudinal cohort of 40 Lyme disease patients and 20 healthy controls, we identified 10 proteins with significantly altered serum levels in patients at the time of diagnosis, and we also developed a 10-protein panel identified through multivariate analysis. In an independent cohort of patients with erythema migrans, six of these proteins, APOA4, C9, CRP, CST6, PGLYRP2, and S100A9, were confirmed to show significantly altered serum levels in patients at time of presentation. Nine of the 10 proteins from the multivariate panel were also verified in the second cohort. These proteins, primarily innate immune response proteins or proteins specific to liver, skin, or white blood cells, may serve as candidate blood biomarkers requiring further validation to aid in the laboratory diagnosis of early Lyme disease.

Three dimensional Pt island-on-Au architectures coupled with graphite carbon nitride nanosheets for effective photo-accelerated methanol electro-oxidation.

Two dimensional (2D) visible-light-activated graphite carbon nitride (CN) nanosheets were used to deposit the traditional electrocatalyst of Pt and Au through a facile one-pot hydrothermal approach. By adjusting different amount of Pt and Au, 3D Pt island-on-Au architectures were formed on the surface of CN nanosheets (Pt-Au/CN). The obtained Pt-Au/CN composite was used for electrocatalytic methanol oxidation reaction (MOR). Comparing with Pt/CN modified electrode, Pt-Au/CN exhibited 13.8 times enhancement on the electrocatalytic activity of MOR. Interestingly, when Pt-Au/CN composite was illuminated with visible light, the current density and stability were continuously enhanced by evaluating of cyclic voltammetry (CV), chronopoenttiometric (CP), chronoamperometry (CA), and electrochemical impedance spectra (EIS). The bimetallic electronic effects of Pt and Au; 3D Pt islands-on-Au architectures; 2D support nanosheet of CN, and the synergistic effect of photo- and electro-catalytic processes resulted in the improved electrocatalytic activity and stability. The present investigations provide a promising future to construct highly efficient electrocatalyst by combining bimetal on semiconductor support and with the assistance of visible light irradiation.

Plasmonic hot electron transfer in anisotropic Pt-Au nanodisks boosts electrochemical reactions in the visible-NIR region.

Anisotropic plasmonic metals have attracted significant attention in enhancing the catalytic performance of catalysts due to their broad light-harnessing capabilities and active hot electrons; however, limited investigations have been dedicated towards improving their electrochemical reaction performance in the visible and near infrared (NIR) regions. Herein, anisotropic Pt-edged Au nanodisks (NDs) were synthesized by controlling the preferential loading of Pt and used as catalysts for plasmon-enhanced electrochemical methanol oxidation reactions (MORs) under visible-NIR light irradiation by, and the light-enhanced electric current over the Pt-edged Au NDs was found to be 3-fold higher than that under dark conditions. Wavelength-dependent electric current over the Pt-edged Au NDs for the MOR in the visible-NIR light region demonstrates that the light-induced enhancement of the electric current is due to surface plasmon resonance (SPR) of the Au NDs. Furthermore, plasmonic hot electron transfer was studied by the single-particle photoluminescence images and spectra of Au NDs and Pt-Au NDs, and the dipole surface plasmon resonance (DSPR) mode was proved to be the main channel for hot electron transfer. During the electrochemical reaction under visible-NIR light irradiation, a plasmonic hot electron is transferred to the electrode, and a "hot hole" is left on the surface, boosting the MOR.

SREBP1, targeted by miR-18a-5p, modulates epithelial-mesenchymal transition in breast cancer via forming a co-repressor complex with Snail and HDAC1/2.

The progression of localized breast cancer to distant metastasis results in a poor prognosis and a high mortality rate. In this study, the contributions of miRNAs to tumor progression and the regulatory mechanisms leading to their expression alterations were investigated. Using highly lung-metastatic sub-lines from parental breast cancer cells, miRNA expression profiling revealed that the miR-17-92 cluster is significantly downregulated and the miR-18a-5p is the most evidently decreased. Ectopic expression and inhibition of miR-18a-5p demonstrated its capacity in suppressing migration and invasion of breast cancer cells. Further research identified sterol regulatory element binding transcription protein 1 (SREBP1), the master transcription factor that controls lipid metabolism, as a candidate target of miR-18a-5p. SREBP1 is overexpressed and strongly associated with worse clinical outcomes in breast cancer. Functionally SREBP1 promotes growth and metastasis of breast cancer both in vitro and in vivo. To unravel the underlying mechanism of SREBP1-mediated metastasis, mRNA profiling and subsequent gene set enrichment analyses (GSEA) were performed and SREBP1 was demonstrated to be significantly associated with epithelial-mesenchymal transition (EMT). Furthermore, SREBP1-mediated repression of E-cadherin was found to be deacetylation dependent and was augmented by recruiting Snail/HDAC1/2 repressor complex. In the light of these data, we propose that reduced expression of miR-18a-5p and concomitant overexpression of SREBP1 lead to induction of EMT states that in turn, promote breast cancer progression and metastasis. Taken together, our study reveals the crucial role of miR-18a-5p and SREBP1 in the EMT and metastasis, thus providing promising drug targets for tailored therapy in the advanced breast cancer setting.

Plasmon enhanced electrocatalytic oxidation of ethanol and organic contaminants on gold/copper iodide composites under visible light irradiation.

In this paper, plasmonic photoelectroncatalyst of gold/copper iodide (Au/CuI) was synthesized and fully characterized. Compared to traditional electrocatalytic procedure under dark condition, the photoelectrocatalytic (PEC) activities of Au/CuI towards ethanol oxidation and organic pollutant degradation were distinctly enhanced under visible light irradiation. The advantages of the PEC process were investigated by photocurrent responses, linear sweep voltammetry, chronoamperometric and chronopotentiometry curves, and electrochemical impedance spectroscopy spectra. Finally, the mechanism of plasmon enhanced PEC performance in ethanol oxidation and organic contaminant degradation under visible light irradiation was proposed. The current studies open a new possibility in the application of ethanol oxidation and organic contaminant degradation by using plasmonic photoelectrocatalysts under visible light irradiation.

Upregulation of miR-520b promotes ovarian cancer growth.

Ovarian cancer is the most common gynecological malignant cancer in female genitalia. Dysregulation or dysfunction of microRNAs (miRs) contribute to cancer development. The role of miR-520b in ovarian cancer remains unclear. The present study investigated the role of miR-520b in ovarian cancer and determined that the expression levels of miR-520b in ovarian cancer tissues and cell lines were upregulated. By contrast, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry revealed that the mRNA and protein expression levels of ring finger protein 216 (RNF216) were downregulated in ovarian cancer, indicating that there was a negative correlation between miR-520b and RNF216. In miR-520b-knockdown cells, downregulation of miR-520b reduced cell proliferation, while upregulation of miR-520b promoted cell proliferation. In addition, RNF216 was predicted by TargetScanHuman and was observed to be targeted by miR-520b. In conclusion, the present data indicated that high expression of miR-520b in ovarian cancer promoted cell growth via RNF216.

CuI as Hole-Transport Channel for Enhancing Photoelectrocatalytic Activity by Constructing CuI/BiOI Heterojunction.

In this paper, CuI, as a typical hole-transport channel, was used to construct a high-performance visible-light-driven CuI/BiOI heterostructure for photoelectrocatalytic applications. The heterostructure combines the broad visible absorption of BiOI and high hole mobility of CuI. Compared to pure BiOI, the CuI/BiOI heterostructure exhibited distinctly enhanced photoelectrocatalytic performance for the oxidation of methanol and organic pollutants under visible-light irradiation. The photogenerated electron-hole pairs of the excited BiOI can be separated efficiently through CuI, in which the CuI acts as a superior hole-transport channel to improve photoelectrocatalytic oxidization of methanol and organic pollutants. The outstanding photoelectrocatalytic activity shows that the p-type CuI works as a promising hole-transport channel to improve the photocatalytic performance of traditional semiconductors.

Enzyme-linked, aptamer-based, competitive biolayer interferometry biosensor for palytoxin.

In this study, we coupled biolayer interferometry (BLI) with competitive binding assay through an enzyme-linked aptamer and developed a real-time, ultra-sensitive, rapid quantitative method for detection of the marine biotoxin palytoxin. Horseradish peroxidase-labeled aptamers were used as biorecognition receptors to competitively bind with palytoxin, which was immobilized on the biosensor surface. The palytoxin: horseradish peroxidase-aptamer complex was then submerged in a 3,3'-diaminobenzidine solution, which resulted in formation of a precipitated polymeric product directly on the biosensor surface and a large change in the optical thickness of the biosensor layer. This change could obviously shift the interference pattern and generate a response profile on the BLI biosensor. The biosensor showed a broad linear range for palytoxin (200-700pg/mL) with a low detection limit (0.04pg/mL). Moreover, the biosensor was applied to the detection of palytoxin in spiked extracts and showed a high degree of selectivity for palytoxin, good reproducibility, and stability. This enzyme-linked, aptamer-based, competitive BLI biosensor offers a promising method for rapid and sensitive detection of palytoxin and other analytes.