Wide Linear Detection Research Articles

MnO2 nanoparticles enhance the activity of the Zr-MOF matrix electrochemical sensor for efficiently identifying ultra-trace tetracycline residues in food.

Anovel nanobiosensor was constructed by in situ locating nanometer MnO2 particles with controllable size and morphology in a Zr-MOF substrate to serve as an electrochemical probe. The synergistic effect of the two components, Zr-MOFs with high specific surface area and compatibility as a carrier for MnO2, resulted in improved electrochemical activity and excellent electrochemical identification performance for the MnO2@Zr-MOF/GCE biosensor. Under optimized experimental conditions and using CV and DPV technology, the biosensor showed a wide linear detection range (2-200μM), a low detection limit (2.577 × 10-8M), a recovery range (106.26-115.01%), and maximum relative standard deviation (5.155) for tetracycline(TC) identification. The recognition mechanism of the sensor was investigated adopting Laviron adsorption theory. The applicability of the sensor was verified through practical measurements. Overall, the MnO2 @Zr-MOF/GCE sensor possesses the advantages of fast analysis speed, high sensitivity, high selectivity, and simple operation, making it suitable for detecting trace amounts of TC in food.

Enhanced Vitamin B12 Detection Using a CxNixOyFeyOx+3 Bimetal-Organic Framework: A Comprehensive Electrochemical Study

The functions of neurons and blood cells are aided by vitamin B12. Serum vitamin B12 levels are picomolar, and their deficiencies may be remedied using vitamin B12 tablets. Consequently, sensitive and selective vitamin B12 detectors that can be used at the point-of-care for food, pharmaceutical, and biological samples are urgently needed. In this study, we present the synthesis and carbonization of a Ni- and Fe-based bimetallic organic framework for the electrochemical sensing of vitamin B12. The crystalline nature and functional groups of the material were analyzed using X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy, and the oxidation states within the framework were determined using X-ray photoelectron analysis. Field-emission scanning electron microscopy revealed a uniform spherical morphology with particle sizes ranging from 2 to 10 nm. Electrochemical analysis was performed to detect vitamin B12 by cyclic voltammetry (CV) on a screen-printed carbon electrode modified with CxNixOyFeyOx+3. CV analysis revealed that the fabricated electrode exhibits excellent redox peaks at approximately 0.0245 and -0.514 V with a low detection limit of 49 nM for vitamin B12 and a wide linear detection range up to 200 µM. Interference studies confirmed the selectivity of the sensor with minimal impact from common biomolecules and inorganic ions. The sensor demonstrated excellent repeatability (RDS = 3.5%), reproducibility, and long-term stability, retaining 94% of its initial current response for over 20 d. The real sample analysis of commercial vitamin B complex tablets demonstrated a recovery rate of 98.59%, highlighting the practical applicability of the sensor in pharmaceutical analysis.

Hierarchical Nanostructured Copper by Dealloying MnCu Alloy Ribbon for High-Performance Glucose Sensing

Electrochemical glucose sensing is vital for biomedical applications, particularly in diabetes management and continuous health monitoring. Among electrochemical sensors, non-enzyme-based sensors offer advantages such as cost-effectiveness, robust anti-interference capabilities, and environmental stability compared to enzyme-based ones. This study focuses on the development of non-enzyme-based glucose sensors utilizing hierarchical nanostructured copper (Cu) electrodes. The electrodes are fabricated by selectively dissolving components from an alloy precursor. Specifically, MnCu alloy ribbons prepared by melt rolling were used due to their favorable properties, and electrochemical dealloying was employed to create nanostructured Cu with high electrocatalytic activity for glucose oxidation. Three-dimensional bicontinuous nanoporous copper with an average pore size of 34 nm~86 nm and an average ligament size range of 45 nm~125 nm can be obtained. The optimized hierarchical nanostructured Cu electrodes exhibited excellent performance, including high sensitivity (0.652 mA·mM⁻1·cm⁻2), a wide linear detection range (0.001 mM to 1.5 mM), a low detection limit (0.73 μM), and a rapid response time. This work demonstrates the potential of nanostructured Cu in the advancement of non-enzyme-based glucose sensors.

An Acid-Resistant Lanthanide Metal-Organic Framework Based on Tetraphenylethylene as an Electrochemical Nitrite Sensor.

Nitrite (NO2-) is attracting increasing attention due to its harmful effect on human health. Thus, it is highly desirable to construct effective electrochemical sensors to detect the presence of NO2-. The majority of electrochemical NO2- detection is focused on alkaline or neutral electrolyte solutions and is rarely reported under acidic conditions. In this work, a tetraphenylethylene (TPE)-based 2D lanthanide metal-organic framework (Ln-MOF), (Me2NH2)[HoIII(tcbpe-F)DMF]•DMF•H2O (1) (tcbpe-F = 4',4‴,4″‴,4″″‴-(ethene-1,1,2,2-tetrayl)tetrakis(3-fluoro-[1,1'-biphenyl]-4-carboxylic acid, DMF = N,N-dimethylformamide)), has been successfully fabricated on carbon paper (CP) by an in situ hydrothermal method. As a NO2- sensor, the fabricated 1 electrode exhibited excellent electrochemical performance in the H2SO4 electrolyte (pH = 1) and offers high sensitivities of 1453.2 and 591.5 μA mM-1 cm-2, with a wide linear detection range of 0.1 μM to 9 M, a low detection limit of 60 nM, excellent specificity even in the presence of various analytes (metal ions, anions, and organic molecules) and real water samples, satisfactory stability, and reproducibility. This is the first report of TPE-based Ln-MOF as a NO2- sensor, and furthermore, a plausible sensing mechanism is confirmed by experiments and theoretical computations.

Novel surfactant-free electro-nanofabricating strategy for highly sensitive and selective colorectal cancer MicroRNA analysis

A label-free nanostructured electrochemical biosensor utilizing graphene quantum dot (GQD) decorated with gold nanoparticles (AuNPs), known as Au-GQD-NS, is presented to colorectal cancer (CRC) biomarker early detection, micro RNA-223 (miR-223). Thiolated DNA probes (Cap-223) are immobilized onto a fabricated and highly conductive nanostructure platform, which improves accessibility and miR-223 recognition. To analyze the nanostructured surface, various sophisticated techniques such as FESEM, EDAX, AFM, and electrochemical approaches are employed. Electrochemical approaches including DPV, EIS, and CV are applied to investigate the electroactivity of substrate, immobilization of Cap-223 on Au-GQD-NPs and subsequent hybridization with the miR-223. The electro-nanofabricated biosensor showcases a wide linear detection range (zepto M to nano M) with an impressively suitable LOD (0.024 atto M). The biosensor selectivity is demonstrated through discrimination studies between target and mismatched miRNA sequences (miR-9 and miR-21). This biosensor also exhibits significant potential for quantitative evaluation of miR-223 in real samples, enabling its applications in point-of-care (POC) detection of CRC. In addition, the Au-GQD-NS substrate is nano-fabricated in absent of surfactants and stabilizers, providing secure anchors for immobilization of cap-223. The well-established strategies for cap-223 immobilization and hybridization with miR, combined with superior electron exchange rate compared to uncovered FTO, upgrade the biosensor’s execution. Significantly, the biosensor demonstrates efficient miR-223 detection in human serum. Overall, this nano-fabricated biosensor shows great promise for miR-based early detection of CRC, and therefore, offering great sensitivity, selectivity, and favorable hydrophilicity for translational medicine investigation and clinical applications.

ZnO nanorods grown on Cu wire mesh provide a high sensitivity non-enzymatic absorbance glucose sensor.

Ahighly sensitive non-enzymatic absorption-based glucose sensor is introducedthat combines ZnO nanorods with the ferrous oxidation-xylenol orange (FOX) assay. ZnO nanorods were successfully synthesized on the surface of a copper wire mesh, exhibiting high crystallinity, purity, and a large surface area. The glucose sensor displays a high sensitivity of 0.394mM-1 in a wide linear detection range (0 - 6mM), along with a low limit of detection of 0.25mM. The proposed assay has an excellent selectivity towards glucose comparedwithother sugars such as sucrose, maltose, and fructose. The potential use of the non-enzymatic absorbance sensor for diabetes monitoring is demonstrated by measuring the glucose concentration in human blood serum, obtaining values that are consistent with clinical analysis.

A Multi-Channel Handheld Diagnostic Device Based on Green Biomimetic Material for Point-of-Care Testing of Vitamin C in Human Fluids.

In the era of "Great Health", maintaining an appropriate level of vitamin C is crucial for human health as it directly impacts the proper functioning of the immune system. In this study, a handheld nonenzymatic electrochemical sensor based on biomimetic material prussian blue functionalized polydopamine is proposed for point-of-care testing (POCT) of vitamin C in human fluids. Particularly, Prussian blue, known as a bio-antidote, and polydopamine, a main component of cuttlefish ink, ensure the safety and reliability of home testing. The experimental results quantitatively demonstrate that this electrochemical POCT sensor enables rapid and accurate determination of vitamin C with a wide linear detection range from 0.2 to 200µm, a low limit of detection at 0.03µm, and high sensitivity at 0.33µAµm-1cm-2. More importantly, the performance evaluation using human urine and saliva samples confirms satisfactory accuracy and recovery rates for vitamin C determination by this electrochemical POCT sensor. Thus, the proposed handheld electrochemical POCT sensor holds potential utility as an affordable tool for VC determination and home-based healthcare.

Bi-MOF-based point-of-care testing paper for dual-mode detection of H2S

Hydrogen sulfide (H2S) is noxious gas and significantly threatens human health. Herein, a Bi-based metal-organic frameworks (Bi-MOFs) based paper analysis device (PAD) has been developed for rapid and effective dual-mode detection of H2S. The dominant H2S sensing mechanism is explored. The H2S can react with Bi-MOF to form bismuth sulfide (Bi2S3) MOF (Bi2S3-MOF), changing the color of PAD from white to black. The distinguish color change makes it very convenience for visible detection. Meanwhile, the generated Bi2S3-MOF exhibits excellent photothermal property, endowing it possible for photothermal imaging detection. In this regard, the PAD boasts a wide linear detection range of 0–40 μM for H2S with an impressively low limit of detection (LOD) (0.23 μM). The constructed sensing system is demonstrated with outstanding selectivity and storage stability. Satisfied recovery is reached for H2S detection in diverse real samples. Interestingly, the PAD can be used as intelligent label for assessing meat freshness by monitor H2S release from meat under different storage temperatures. With integration capabilities of smartphones, the portable and user-friendly PAD offers a simple and rapid solution for on-the-go detection of H2S in food and environment. The investigation provides an instructive way for environment monitoring and food safety guarding.

Germanium-incorporated Si-Ge-Si heterojunction phototransistors for a high-limit of detection and wide linear dynamic range near-infrared light detection

This paper investigates overcoming the limitations of conventional silicon (Si) bipolar junction transistors (BJTs) for near-infrared (NIR) light detection. Silicon BJTs have inherent limitations in the NIR region due to silicon’s bandgap. To address this, the paper proposes high-performance silicon-germanium-silicon (Si-Ge-Si) heterojunction bipolar phototransistors (HPTs). The key innovation is introducing a thin germanium (Ge) layer at the base-collector junction and engineering its doping concentration. This Ge layer extends the BJT phototransistor’s optical response into the NIR region by enhancing optical absorption. The paper analyses the performance of the HPTs, demonstrating linear photoresponsivity of 432 mA/W over a wide optical power range, leading to an exceptional linear dynamic range of 159 dB and a very low dark current, which produces a limit of detection of -99.64 dBm. Additionally, the device exhibits a large photo-to-dark current ratio of 2.16 ×107 (at optical power of 5 µW) and a fast response time of 11.35 ps to modulated NIR optical signals within the linear dynamic range. This research paves the way for high-performance CMOS-compatible NIR phototransistors using Si-Ge-Si heterostructures.

Non-invasive ultra-sensitive detection of breast cancer biomarker using cerium nanoparticle functionalized graphene oxide enabled impedimetric aptasensor

Epidermal growth factor receptor (EGFR) is a transmembrane protein and a key biomarker implicated in the pathogenesis of breast cancer. Early and precise detection of EGFR is crucial for effective diagnosis, prognosis, and therapeutic intervention. However, conventional EGFR detection techniques, such as biopsy and immunohistochemistry, are often invasive, time-consuming, and limited in sensitivity, highlighting the demand for non-invasive, highly sensitive detection methods. In this study, we fabricated a cerium oxide (CeO₂) and graphene oxide (GO) nanocomposite-based aptasensor for the non-invasive detection of EGFR using electrochemical impedance spectroscopy (EIS). The CeO₂-GO nanocomposite was synthesized via the sol-gel method and characterized through UV–Vis spectroscopy, FTIR, TEM, and XRD, confirming the crystalline structure of hexagonal CeO₂ nanoparticles on amorphous GO sheets. The nanocomposite was functionalized with aptamers specific to EGFR using covalent coupling reactions. The EIS analysis of the fabricated aptasensor (GCE/CeO₂-GO/EGFR-Apt/BSA) demonstrated a wide linear detection range from 10 fg mL-1 to 100 ng mL-1, with an ultralow detection limit of 1.87 fg mL-1 in PBS, 3.16 fg mL-1 in serum, 5.31 fg mL-1 in sweat, and 6.14 fg mL-1 in saliva samples. These results highlight the aptasensor's high sensitivity, specificity, and potential for real-time, non-invasive EGFR monitoring in clinical samples such as serum, sweat, and saliva. This approach would facilitate early detection of cancer and personalized diagnostics in point-of-care settings.

Solvothermal synthesis of Zr-metal-organic framework/V2C MXene based composite on nickel foam for highly selective detection of epinephrine in simulated blood serum

Metal-organic frameworks (MOFs) combined with MXene materials have recently gained considerable attention for their unique properties, including exceptional structural characteristics and electrical conductivity. These attributes enable them to maintain a high concentration of electroactive sites, making them particularly suitable for electrochemical applications. Here, we demonstrate solvothermal synthesis of Zr-metal–organic framework (Zr-MOF)/V2C MXene composite decorated nickel foam (NF) for electrochemical detection of Epinephrine (EP) in simulated blood serum samples. X-ray diffraction analysis confirms the formation of the cubic structured Zr-MOF/V2C MXene composite. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) reveal the existence of numerous rectangular sheets and nanospheres of the composite. Utilizing the differential pulse voltammetry (DPV) technique, the sensor demonstrates a remarkable sensitivity of 19 µA/µM.cm−2 to EP within a wide linear detection range from 1 µM to 1 mM with a lower limit of detection of 0.86 µM (=3 S/m). The fabricated sensor exhibits high selectivity against interfering species like uric acid (UA), ascorbic acid (AA), glucose (GLU), urea, etc. Real-sample analysis conducted in simulated blood samples using the standard addition method showcases an outstanding recovery percentage of approximately 100 %. Zr-MOF/V2C MXene composite, with its conductive nature and high surface area, forms a robust interaction with EP, leading to a significant alteration in the sensor’s electrical properties. Meanwhile, the porous NF substrate is crucial in maintaining stability, boosting catalytic activity by offering numerous active sites, and enabling swift electron transfer. Affirming the efficacy of the Zr-MOF/V2C MXene composite, herein, as an exceptional electrode with high performance. The composite shows significant promise in detecting various biomolecules essential for biomedical research applications.

A novel label-free impedance biosensor for KRAS G12C mutations detection based on PET-RAFT and ROP synergistic signal amplification

The KRAS G12C mutations, as crucial biomarkers, are closely associated with non-small cell lung cancer. Here, a novel label-free electrochemical biosensor with synergistic signal amplification of photocell energy transfer-reversible addition fragmentation chain transfer (PET-RAFT) and ring-opening polymerization (ROP) was developed for the first time for sensitive detection of KRAS G12C mutations. Specifically, hairpin DNA (hDNA), which act as biomolecular probe, was self-assembled on Au electrode surface by Au-S bond. 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl] pentanoic acid (CDTPA), the chain transfer agent of PET-RAFT reaction, was then attached to hDNA via amide bond. After that, the target DNA (tDNA) was captured on the electrode surface by complementary base pairing with hDNA. Subsequently, large numbers of electro-active monomers N-acryloxysuccinimide (NAS) were successfully grafted to the electrode surface via PET-RAFT reaction, which provided plenty of junction sites for doxorubicin-polycaprolactone (Dox-PCL) synthesized by ROP. Finally, the Dox-PCL was connected to the electrode surface by ester bond, significantly amplifying the electrochemical signal. Under optimized conditions, the biosensor has a wide linear detection range of 0.1 pM to 1 μM, with a detection limit of 86.9 fM. Attribute to its high sensitivity, specificity, reproducibility and stability, this biosensor possesses considerable potential in early diagnosis of disease and biomedical research.

Molecular imprinting sensor based on zeolitic imidazolate framework derived Co, N-doped carbon loaded on reduced graphene oxide toward the determination of dopamine.

Anovel voltammetric sensor designed for dopamine(DA) detectionis presented utilizing a combination of zeolitic imidazolate framework (ZIF-67) derived cobalt and nitrogen-doped carbon on reduced graphene oxide (Co-N-C/rGO). ZIF-67 cubic crystals were synthesized in situ and deposited onto the graphene oxide (GO) surface through room-temperature reactions. High-temperature calcination resulted in partially collapsed cubic and spherical carbon, while simultaneously reducing GO to rGO. A molecular imprinting resorcinol polymer (MIP) membrane was also in situ applied to the Co-N-C/rGO/glassy carbon electrode (GCE) via electropolymerization. Analyses using cyclic voltammetry, electrochemical impedance, and pulse voltammetry reveal that the modified MIP/Co-N-C/rGO/GCE electrodes show improved electroconductivity and notable electrochemical reactivity towards dopamine. After optimizing detection parameters, the sensor demonstrates a wide linear detection range of 0.01-0.5 and 0.5-100μmol/L, with a limit of detection (LOD) of 3.33nmol/L (S/N = 3). Additionally, the sensor displays strong robustness, including excellent selectivity, significant resistance to interference, and long-term stability. It also shows satisfactory recovery in detecting spiked real samples.

Copper-Based Electrochemical Sensor Derived from Thiosemicarbazide for Selective Detection of Neurotransmitter Dopamine.

This paper presents the synthesis of the ligand 1-picolinoyl-4-cyclohexyl-3-thiosemicarbazide (H2pctc) and new metal complexes [Ni(Hpctc)2] (1), [Cu(Hpctc)Cl] (2), and [Cd(Hpctc)2] (3). The synthesized metal complexes were precisely characterized using single crystal X-ray diffraction (SC-XRD). In addition, complexes 1-3 were also characterized by UV-vis, fluorescence, and infrared spectroscopy. SC-XRD data confirmed the distorted octahedral geometry around the Ni(II) and Cd(II) centers and the distorted square planar geometry around the Cu(II) center. Data derived from the emission spectra depict that higher fluorescence intensity was exhibited by complexes 1, 2, and 3 in comparison to that of the free ligand H2pctc, and complex 3 showed the maximum intensity. Further, these metal complex-modified GCEs (glassy carbon electrodes) were utilized for electrochemical sensing of dopamine (DPM). The electrochemical studies of these complexes were performed using modified glassy carbon electrodes supported by electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. In contrast to complexes 1 and 3, complex 2 is a superior electrode material with a high effective surface area for the electrochemical oxidation of DPM, according to the electrochemical response results. The derived sensor had a wide linear detection range of 1 to 1400 μM, an acceptable sensitivity of 0.01531 μA cm-2 μM-1, and a low LOD of 0.38 μM. The proposed approach was free of the interfering effects of ascorbic acid, uric acid, aminophenol, and other substances. During the successive scans, no fouling of the electrode surface was observed. The proposed electrochemical sensor had excellent stability, sensitivity, and a low detection limit making it suitable for the analysis of a variety of real samples. Additionally, it was proven to be useful for analyzing biological fluids.

Mo-doped carbon-dots nanozyme with peroxide-like activity for sensitive and selective smartphone-assisted colorimetric S2− ion detection and antibacterial application

Sulfur ion (S2−) plays a significant and considerable role in many living organisms and ecosystems, while its abnormal content can pose a serious hazard to human health and ecological environment. Hence, it is extremely meaningful to construct a highly sensitive and selective analytical platform for S2− detection in complex microenvironment, particularly in biological systems. In this study, phosphomolybdic acid and L-Arg were utilized to prepare a new molybdenum doped carbon-dots nanozyme (Mo-CDs) with great peroxidase-like activity by one-step hydrothermal approach. In the presence of H2O2, Mo-CDs converted 3,3′,5,5′-tetramethyl benzidine (TMB) into blue oxTMB, but S2− strongly reduced the blue solution to colorless and then brown, which established significant selectivity toward S2−. Mo-CDs illustrated a wide linear range (2.5 μM–900 μM) and low detection limit (LOD = 76 nM) by ultraviolet and smartphone-assisted visualized colorimetric analysis. Especially, the smartphone-assisted analysis platform successfully realized quick, portable, sensitive and visible identification of S2− with high recovery (95.7–106.7 %) and excellent specificity in water samples. More importantly, Mo-CDs was developed to antibacterial applications based on good peroxidase-like activity. This research not only constructed a new and efficient carbon-dots nanozyme and a low-cost, portable, visual analysis platform for real-time detection of S2−, but also proposed a novel design strategy and methodology for exploiting multifunctional nanozyme detection tool with great practical application.

Biological Ce/Fe-metal organic framework multifunctional nanozyme-based colorimetric sensor array for multi-analyte detection in human sweat

Diabetes, a widespread metabolic disorder, is a major public health concern. To address the ongoing need for effective diagnosis, a novel approach has been developed that allows the rapid, low-cost, and ultra-sensitive detection of disease-specific biomarkers in various body fluids using a single platform. Notably, this method focuses on biomarkers found in human sweat—glucose, L-Tryptophan, uric acid, and acetone—that are indicative of diabetes. The new strategy involves a nanozyme-based colorimetric sensor array made from a Ce/Fe fumarate biological metal–organic framework (Ce/Fe-Fum Bio-MOF) doped with Cu and Ni, and further enhanced with Ag nanoparticles. This nanozyme displays multiple enzyme-like activities, which result in distinct color changes when tested with specific chromogenic substrates. When these color changes are reduced by the introduction of biomarkers, the results can be easily captured using a smartphone. This method offers a wide linear detection range (20–1000 µM) and low detection limits for each biomarker, showing strong selectivity, reproducibility, and practical performance in detecting biomarkers in human sweat samples. The integration of smartphone signaling with this sensor array creates potential for a portable, handheld device for point-of-care applications, and could also be adapted for other sensing and biosensing needs. This colorimetric assay marks a significant advancement in the detection of diabetes biomarkers and the development of point-of-care diagnostic systems.

A-347 A Comprehensive Exdia TRF-LFIA for Simultaneous Quantification of GFAP and NT-proBNP in Distinguishing Ischemic and Hemorrhagic Stroke

Abstract Background The goal of this study is to create a highly sensitive time-resolved fluorescence lateral flow immunoassay (TRF-LFIA) capable of concurrently measuring glial fibrillary acidic protein (GFAP) and the N-terminal fragment of B-type natriuretic peptide precursor (NT-proBNP). This assay is designed as a diagnostic tool and aims to provide an algorithm for stroke management, specifically for distinguishing between Ischemic stroke (IS) and Hemorrhagic stroke (HS). However, LFIA to quantify simultaneous serum NT-proBNP and GFAP are not yet available. Methods We have developed and validated a novel TRF-LFIA for the simultaneous quantitative detection of NT-proBNP and GFAP. The sensitivity and reproducibility of the immunoassay were significantly improved by employing specific monoclonal antibodies linked to europium nanoparticles (EuNPs) that specifically target NT-proBNP and GFAP. The detection area on the nitrocellulose membrane featured sandwich-style complexes containing three test lines for NT-proBNP, GFAP, and Control. The fluorescence intensity of these test lines on the nitrocellulose membrane was measured using an in-house developed Exdia TRF-Plus analyzer. As proof-of-concept, we enrolled patients suspected of having a stroke who were admitted within a specific time frame (6 hours). A small amount of clinical specimen (serum) was used with a well-assembled cartridge for the measurement of GFAP and NT-proBNP. Results To optimize the LFIA, an EuNPs conjugated antibodies were investigated to improve the detection sensitivity and decrease the background signal as well shorten the detection time. The Exdia TRF-LFIA cartridge offers a wide linear dynamic detection range, rapid detection, high sensitivity, and specificity. The limit of detection was determined to be 98 pg/mL for NT-proBNP and 68 pg/mL for GFAP, with minimal cross-reactivity. There were 200 clinical human serum samples that were used to evaluate this platform with high correlation. By combining the results of NT-proBNP and GFAP, we formulated an algorithm for the clinical assessment of Ischemic Stroke (IS) and Hemorrhagic Stroke (HS). According to our proposed algorithm, the combination of GFAP and NT-proBNP emerged as the most effective biomarker combination for distinguishing between IS and HS. Conclusions Exdia TRF-LFIA shows great potential as a supplemental method for in vitro diagnostics in the laboratory or in other point-of-care testing (POCT) applications. Its development substantially decreases the diagnosis time for IS and HS. The proposed algorithm not only minimizes treatment delays but also lowers medical costs for patients.

Highly Specific Non-Enzymatic Electrochemical Sensor for the Detection of Uric Acid Using Carboxylated Multiwalled Carbon Nanotubes Intertwined with GdS-Gd2O3 Nanoplates in Human Urine and Serum.

Herein, the electrochemical sensing efficacy of carboxylic acid functionalized multiwalled carbon nanotubes (C-MWCNT) intertwined with coexisting phases of gadolinium monosulfide (GdS) and gadolinium oxide (Gd2O3) nanosheets is explored for the first time. The nanocomposite demonstrated splendid specificity for nonenzymatic electrochemical detection of uric acid (UA) in biological samples. It was synthesized using the coprecipitation method and thoroughly characterized. The presence of functional groups and disorder in the as-synthesized nanocomposite are confirmed using Fourier transform infrared spectroscopy and Raman spectroscopy. Furthermore, field emission scanning electron microscopy, high-resolution transmission electron microscope, X-ray powder diffraction, and X-ray photoelectron spectroscopy provides a clear understanding of the morphology, coexisting phases, and elemental composition of the as-synthesized nanocomposites. The differential pulse voltammetry technique was utilized to elaborate the electrochemical sensing of UA using a GdS-Gd2O3/C-MWCNT modified glassy carbon electrode (GCE), The sensor showed an enhanced current response by more than 2-fold compared to bare GCE. Also, the sensor's performance was further improved by dispersing the nanocomposite in an ionic liquid with the exceptional reproducibility (SD = 0.0025, n = 3). The fabricated UA sensor GdS-Gd2O3/C-MWCNT/IL/GCE demonstrated a wide linear detection range from 0.5-30 μM and 30-2000 μM, effectively covering the entire physiological range of UA in biological fluids with a limit of detection (LOD) of 0.380 μM (+3SD of blank) and a sensitivity of 356.125 μA mM-1 cm-2. Moreover, the electrodes exhibited storage stability for 2 weeks with decrease in zero-day current by only 4.5%. The sensor was validated by quantifying UA in 12 unprocessed clinical human urine and serum samples, and its comparison with the gold standard test yielded remarkable results (p < 0.05). Hence, the proposed nonenzymatic electrochemical UA sensor is selective, sensitive, reproducible, and stable, making it reliable for point-of-care diagnostics.

Electrochemical Detection of H2O2 Using Bi2O3/Bi2O2Se Nanocomposites.

The development of high-performance hydrogen peroxide (H2O2) sensors is critical for various applications, including environmental monitoring, industrial processes, and biomedical diagnostics. This study explores the development of efficient and selective H2O2 sensors based on bismuth oxide/bismuth oxyselenide (Bi2O3/Bi2O2Se) nanocomposites. The Bi2O3/Bi2O2Se nanocomposites were synthesized using a simple solution-processing method at room temperature, resulting in a unique heterostructure with remarkable electrochemical characteristics for H2O2 detection. Characterization techniques, including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirmed the successful formation of the nanocomposites and their structural integrity. The synthesis time was varied to obtain the composites with different Se contents. The end goal was to obtain phase pure Bi2O2Se. Electrochemical measurements revealed that the Bi2O3/Bi2O2Se composite formed under optimal synthesis conditions displayed high sensitivity (75.7 µA µM-1 cm-2) and excellent selectivity towards H2O2 detection, along with a wide linear detection range (0-15 µM). The superior performance is attributed to the synergistic effect between Bi2O3 and Bi2O2Se, enhancing electron transfer and creating more active sites for H2O2 oxidation. These findings suggest that Bi2O3/Bi2O2Se nanocomposites hold great potential as advanced H2O2 sensors for practical applications.

Electrochemical sensor for acetylcholine detection based on WO3 nanorods-modified glassy carbon electrode

Acetylcholine (ACH) is one of the excitatory neurotransmitter in the human body. It is the most abundant neurotransmitter responsible for triggering the activation of postsynaptic neurons, leading to an excitatory response. ACH plays a crucial role in various physiological processes, including muscle contraction, autonomic nervous system regulation, and cognitive functions such as learning and memory. In this study, an electrochemical sensor was prepared based on WO3 nanorods modified glassy carbon electrode for the detection of ACH. The WO3 nanorods provided excellent properties for the electrochemical determination of ACH. The proposed sensor exhibited a wide linear detection range of (0.1 to 400.0 µM) and a low detection limit of 0.025 µM for ACH. These results demonstrate the sensor's high sensitivity in detecting this important neurotransmitter. In addition the developed sensor showed good ability for ACH determination in real samples. This study offers an innovative strategy for the electrochemical detection of ACH, showcasing the potential of nanomaterials in the development of advanced sensing technologies.