Talanta最新文献

Envenomation accidents are usually diagnosed at the hospital through signs and symptoms assessment such as short breath, dizziness and vomiting, numbness, swilling, bruising, or bleeding around the affected site. However, this traditional method provides inaccurate diagnosis given the interface between snakebites and scorpion stings symptoms. Therefore, early determination of bites/stings source would help healthcare professionals select the suitable treatment for patients, thus improving envenomation management. In this study, we developed an innovative multiplexing platform based on dual immunosensors for the simultaneous determination of snake and scorpion venoms using a label-free electrochemical platform. The dual immunosensor was fabricated on graphene/gold nanoparticle modified screen-printed electrodes. The electrodes were first modified with two chemical linkers (cysteamine/phenylene diisothiocyanate) to facilitate the immobilization of the antibodies (antivenoms) through covalent binding. The proposed immunosensor was tested with different venoms that specific to six snake species and two scorpion species. The detection was undergone by monitoring the reduction peak current variation after the venom binding using square wave voltammetry, in presence of ferro/ferricyanide redox system. The dual immunosensor enabled a sensitive and selective simultaneous detection of the snake and scorpion species venoms within wide linear ranges in the limits of detection ranging from 0.057 to 0.027 μg/mL. The applicability of the venoms immunosensor has also been evaluated for the detection of snake and scorpion venoms in human serum samples showing high recovery percentages. These achievements show the great potential of our multiplexing approach for the early detection of snake or scorpion envenomation.

Directly detecting biomarkers in liquid biopsy for diagnosis and personalized treatment plays a crucial role in managing cancer relapse and increasing survival rates. Typically, the standard analysis of circulating tumour DNA requires lengthy isolation, extraction, and amplification steps, leading to sample contamination, longer turnaround time and higher assay costs. Surface plasmon resonance is an emerging and promising technology for rapid and real-time dynamic biomarker monitoring in liquid biopsy. Here, we propose a new SPR imaging biosensing approach to detect tumour DNA circulating in the blood of colorectal cancer patients by exploiting the unique properties of superparamagnetic particles. Micrometer beads functionalized with a biotinylated oligonucleotide can directly capture DNA target sequences bearing single-nucleotide variations of KRAS oncogene in human blood plasma. Mutated and wild-type peptide nucleic acid probes immobilized on an SPR gold surface recognize complementary and non-complementary DNA targets by discriminating a single nucleotide mismatch. The new assay allows for detecting p.G13D mutated DNA in buffer and spiked human plasma at attomolar level (down to 300 copies mL^-1) with minimal sample manipulation and in just a few microliters. The assay was validated using plasma samples from colorectal cancer patients and healthy donors, by discriminating mutated DNA circulating in patients and wild-type DNA found in healthy blood donors. This feature underscores the potential of the liquid biopsy assay as a valuable tool for the diagnosis and monitoring of cancer.

Flavonoid glycosides are formed by dehydration condensation of aglycones and sugar molecules. Therefore, discrimination of flavonoid glycosides from their corresponding aglycones is a challenging task because they contain the same aglycone part in their molecular structures. Herein, boric acid-functional Eu(III)-organic framework (BA-Eu-MOF) was applied to discriminate flavonoid glycosides including baicalin (Bai), wogonoside (Wog), rutin (Rut), puerarin (Pue), quercitrin (Que) and astragalin (Ast) from their corresponding aglycones for the first time. Besides as organic ligand to sensitize the luminescence of Eu³⁺ through "antenna" effect, 5-boronobenzene-1,3 dicarboxylic acid provided recognition site for flavonoid glycosides. Infrared, fluorescence, UV-vis, and mass spectra were used to investigate the recognition reaction between BA-Eu-MOF and flavonoid glycosides. The data indicated that the cis-diols of flavonoid glycosides from sugars covalently bonded to boric acid group to form cyclic boronic esters, which quenched the fluorescence of BA-Eu-MOF at 620 nm through decreasing the intersystem efficiency, inner filter effect and photoelectron transfer. In contrast, aglycones could not alter the fluorescence of BA-Eu-MOF because of no covalent bond between them. This probe exhibited high sensitivity towards flavonoid glycosides with the low detection limits of 3.3 nM, 3.5 nM, 33 nM, 56 nM, 5.1 nM and 5.5 nM for Bai, Que, Wog, Ast, Pue and Rut, respectively. The unique recognition ability of boric acid group enables selective and sensitive detection of flavonoid glycosides without the interference of their corresponding aglycones.

Levels of CA125 are strongly associated with cervical, pancreatic, bowel and breast cancer. However, the common CA125 detection method has the disadvantages of poor repeatability, high cost, easy to be disturbed and poor stability. In this work, a COF based electrochemical immunosensor was developed for the rapid, sensitive and stable detection of CA125. The COF_Dha-Tab synthesized by 2,5-dihydroxyp-phenyldiformaldehyde (Dha) and 1,3,5-tris(4-aminophenyl)benzene (Tab) can better absorb primary antibody (Ab₁) of CA125 after epoxidation, and the COF_DAAQ-TFP synthesized by 2,6-diaminoanthraquinone (DAAQ) and 2,4,6-triformylphloroglucinol (TFP) was modified with AuNPs, which can not only improve the electrochemical performance but also provide a platform for loading secondary antibody (Ab₂). CA125 can be specifically recognized and captured by EP-COF_Dha-Tab adsorbed to Ab₁, which can further bind the signal probe AuNPs@COF_DAAQ-TFP/Ab₂. The signal response of the electroactive molecule COF_DAAQ-TFP is positively correlated with the concentration of CA125 to achieve the quantitative detection of CA125.The sensor exhibited a low detection limit of 0.0067 U/mL and a linear range from 0.01 to 100 U/mL. This work presents a novel approach utilizing electroactive COFs as signal probes for the sensitive and quantitative detection of carbohydrate antigens.

Macrocyclic polymer materials exhibit excellent selectivity and adsorption performance in pollutant adsorption due to unique host-guest recognition. Herein, three kinds of calixarene polymers (C4P, C6P and C8P) were synthesized through Sonogashira reaction, and were characterized through ¹H NMR, FT-IR, SEM, and TEM. The water contact angle experiments revealed that three kinds of calixarene polymers were highly hydrophobic, and they all exhibited high enrichment efficiency for weak polar chloro-substituted benzene compounds (chlorobenzene, o-chlorotoluene, p-dichlorobenzene and o-dichlorobenzene) and BTEX (benzene, toluene, ethylbenzene and xylenes). Surprisingly, three types of calixarene polymers also showed satisfactory enrichment performance for polar nitrobenzene compounds (NBCs). Among them, C8P showed the most outstanding enrichment factors for NBCs (825-1913), which was about 2-7 times better than those of the commercial fibers. Using C8P as coating fiber, a sensitive analytical method was further developed based on solid phase microextraction (SPME), coupled with gas chromatography-mass spectrometry (GC-MS). The established analytical method demonstrated low detection limits (0.06-5.08 ng L^-1), a wide linear range (0.5-1000 ng L^-1), and good repeatability. The established method was further applied to the quantification of NBCs in environmental water samples, verifying its feasibility.

Miniaturized optical emission spectrometric (OES) devices based on various microplasma excitation sources provide a reliable tool for in-situ elemental analysis. The key to improving analytical performance is enhancing the excitation capability of the microplasma source in these devices. Here, dielectric barrier discharge (DBD) and point discharge (PD) technologies are combined to construct an enhanced dual-stage excitation source (called DBD-PD), which improves the overall excitation efficiency and OES signal sensitivity. Specifically, DBD serves as a pre-excitation source in a narrow discharge chamber, significantly reducing energy consumption during breakdown discharge gas, while improving the excitation capability of subsequent PD microplasma. The microplasma parameter characteristics were calculated, and the microplasma state during the excitation process was imaged using a fast-gated intensified charge-coupled device (ICCD) camera, revealing the enhancement mechanism of the DBD-PD excitation source. Compared to other microplasma excitation sources such as DBD, PD and PD-DBD, DBD-PD increased Se and As signal intensity by up to 16.0 and 11.6 times, respectively. Under the optimal conditions, the detection limits of Se and As reached 0.8 and 0.2 μg L^-1, respectively, and the relative standard deviations (RSDs) were less than 5%. The analysis of certified reference materials (GBW07601a and GBW10023) and actual water samples verified the reliability and practicability of the proposed method. This analysis strategy not only offers significant leap in field performance of miniaturized OES devices but also holds extensive potential for broader applications in elemental analysis.

Constrained by detecting techniques, patients with acute promyelocytic leukemia (APL) are often confronted with minimal residual disease (MRD) and a high risk of relapse. Thus, a pragmatic and robust method for MRD monitoring is urgently needed. Herein, a novel split-type electrochemical sensor (E-sensor) was developed by integrating nucleic acid sequence-based amplification (NASBA) with enzyme-linked magnetic microbeads (MMBs) for ultra-sensitive detection of the PML/RARα transcript. In this system, NASBA facilitated efficient amplification under isothermal conditions, generating a large amount of RNA amplicons, which mediated the quick binding between horseradish peroxidase (HRP) and MMBs. The separately HRP-linked MMBs were subsequently transferred onto the surface of magnetic glass carbon electrode, producing a remarkably strong electrochemical signal in the presence of the HRP substrate. The proposed split-type E-sensor could detect the PML/RARα transcript with a high sensitivity (a limit detection of 100 aM), a high specificity (single base discrimination) as well as a high stability (a relative standard deviation of 8.3 % for 10 fM target RNA and 6.0 % for 100 fM target RNA). Finally, it could achieve both direct detection of serum cell-free RNA and specific intracellular RNA detection. Owing to its isothermal characteristics, robustness, and suitability for point-of-care testing, this method offers a powerful tool for the early diagnosis of APL and the monitoring of MRD, which holds a great significance for facilitating treatment response assessment and making treatment decisions.

Precise detection of ultralow-level antibiotics, such as picomole, in aqueous environments is significant for human health, however, it presents a great challenge to the adsorption capacity and electrocatalytic ability of sensing materials. Here, we used a one-step hydrothermal method to in situ grow spindle-like CoFe-based metal-organic frameworks (MOFs) with a size of about 50 nm in the region of hydrophilic MXene-loading hydrophobic carbon paper. By combining MOFs with abundant adsorption sites and MXene with high conductivity, the problems of adsorption and electrons transfer of ultralow-level antibiotics have been solved, and achieving precise detection of picomole-level antibiotics. As a result, the CoFe-MOFs/MXene/HCP sensing electrode exhibits the ultralow limit of detection with 33 pM and a wide detection range with 0.1 nm-2.0 mM for chloramphenicol (CAP) detection, as well as the designed sensor has excellent anti-interference, reproducibility, and stability. Importantly, the prepared sensing electrode exhibits reliable analytical results for CAP in real water samples, such as bottled water, milk, and urine, indicating that the prepared sensors have a great potential for application in the analysis of antibiotics in real samples.

Research on metasurface sensors with high sensitivity, strong specificity, good biocompatibility and strong integration is the key to promote the application of terahertz waves in the field of biomedical detection. However, traditional metallic terahertz metasurfaces have shortcomings such as poor biocompatibility and large ohmic loss in the terahertz frequency band, impeding their further application and integration in the field of biosensing detection. Here, we overcome this challenge by proposing a high-performance terahertz metasurface based on gold nanoparticles and single-walled carbon nanotubes composite film. Compared with metal materials, carbon nanotubes not only have better biocompatibility, which can reduce the potential adverse reactions between metasurfaces and biological samples, but also have strong tunability in electrical and optical properties. Experimentally, we reveal a method to adjust the dielectric properties of single-walled carbon nanotube films by doping with gold nanoparticles. Leveraging this mechanism, we designed and prepared a single-walled carbon nanotube terahertz metasurface composed of periodically arranged asymmetric open resonant rings. Compared with pure single-walled carbon nanotube films, this device based on a composite single-walled carbon nanotube films have better localized electromagnetic field enhancement characteristics. Through integration with microfluidic channels, this metasurface sensor can achieve direct detection of SAA proteins in solution environments at the fM level. In addition, the device also exhibits a detection sensitivity of 41 GHz/fM. This work has not only made significant progress in the design and function of new high-sensitivity carbon-based terahertz metasurfaces, but also laid the foundation for its application in liquid environment detection of trace biological samples.

Cancer biomarkers have been facing some issues such as poor accuracy and low sensitivity in the early diagnosis of tumors. Utilizing biotin-labelled peptide as a mass tag (MT), this work proposes a high-throughput biosensing strategy for matrix-assisted laser desorption/ionization-time of flight mass spectrometric (MALDI-TOF-MS) immunoassay of multiple lung cancer biomarkers. Due to little required dosage, satisfied stability, high sensitivity and accuracy, this method can achieve off-site centralized signal detection after on-site sample incubation. The proposed approach has been successfully applied for the detection of carcinoembryonic antigen (CEA), carbohydrate antigen199 (CA199), carbohydrate antigen 125 (CA125) and cytokeratin-19-fragment (CY211) in serum samples from various stages of non-small cell lung cancer. Based on the analysis of multiple parameters and pathological results, significant differences in biomarkers are found in serum samples of lung cancer patients at different stages. More importantly, the analysis of multiple tumor biomarkers can improve the accuracy and sensitivity of early diagnosis. Therefore, the multiple immunoassay based on MALDI-TOF MS exhibits exceptional performance in terms of high throughput, little sample dosage, stability and sensitivity.