Enhanced Detection Sensitivity Research Articles

Controllable Ultrathin Nickel Nanoislands With Dense Discrete Space Charge Regions: Steering Hole Extraction for High-Performance Underwater Multispectral Weak-Light Photodetection.

Undersea optical communication (UOC) is vital for ocean exploration and military applications. In the dim-light underwater environment, photodetectors must maximize photon utilization by minimizing optical losses and carrier recombination. This can be achieved by integrating ultrathin metal nanostructures with photocatalysts to form Schottky junctions, which enhance charge separation and injection while mitigating metal-induced light shading. The strategic design of discrete metal nanostructures providing numerous high-depth space charge regions (SCRs) without overlap offers a promising approach to optimize hole transport paths and further suppress recombination. Here, a facile phase-separation lithography technique is explored to fabricate tunable ultrathin Ni nanoislands atop n-Si, yielding high-performance photoelectrochemical photodetectors (PEC PDs) tailored for underwater weak-light environments. This results indicate that key determinant of hole extraction behavior is the relationship between the spacing distance of adjacent Ni nanostructures (ds) and twice the SCR radius (Ws). PEC PDs with optimized 8nm ultrathin Ni nanostructures featuring closely but non-overlapping SCRs, exhibit a 55-fold increase in photoresponsivity (2.2mAW-1) and a 128-fold enhancement in detection sensitivity (3.2 × 1011 Jones) at 0V over Ni film, revealing the exceptional stability. Furthermore, this approach enables effective detection across UV-vis-near infrared spectrum, supporting reliable multispectral UOC and underwater imaging capabilities.

Water-Soluble Bimodal Magnetic-Fluorescent Radical Dendrimers as Potential MRI-FI Imaging Probes.

Dual or multimodal imaging probes have become potent tools for enhancing detection sensitivity and accuracy in disease diagnosis. In this context, we present a bimodal imaging dendrimer-based structure that integrates magnetic and fluorescent imaging probes for potential applications in magnetic resonance imaging and fluorescence imaging. It stands out as one of the rare examples where bimodal imaging probes use organic radicals as the magnetic source, despite their tendency to entirely quench fluorophore fluorescence. Opting for organic radicals over metal-based contrast agents like gadolinium (Gd3+)-chelates is crucial to mitigate associated toxicity concerns. We utilized an amino-terminated polyamide dendrimer containing a 1,8-naphthalimide (Naft) fluorescent group, amino acid derivatives as linkers to enhance water solubility, and TEMPO organic radicals as terminal groups. The same dendrimer structure, featuring an equivalent number of branches but lacking the fluorophore group, was also functionalized with amino acid and terminal radicals to serve as a reference. Remarkably, we achieved a fully water-soluble dendrimer-based structure exhibiting both magnetic and fluorescent properties simultaneously. The fluorescence of the Naft group in the final structure is somewhat quenched by the organic radicals, likely due to photoinduced electron transfer with the nitroxyl radical acting as an electron acceptor, which has been supported by density functional theory calculations. Molecular dynamics simulations are employed to investigate how the dendrimers' structure influences the electron paramagnetic resonance characteristics, relaxivity, and fluorescence. In summary, despite the influence of the radicals-fluorophore interactions on fluorescence, this bimodal dendrimer demonstrates significant fluorescent properties and effective r1 relaxivity of 1.3 mM-1 s-1. These properties have proven effective in staining the live mesenchymal stem cells without affecting the cell nucleus.

Exploring the role of graphene-metal hybrid nanomaterials as Raman signal enhancers in early stage cancer detection

Molecular diagnosis plays a significant role in detection of biomolecules linked to early stage cancer since it offers greater sensitivity and reliability for identification of biomarker level changes as the disease progresses. The application of vibrational spectroscopy in biomarker detection is defined by the fingerprint spectrum of a molecule originating from single-molecule vibrations. This characteristic makes surface enhanced Raman spectroscopy (SERS) a promising tool for identification of biomarkers. The performance of the SERS technique largely depends on the material being used as the SERS substrate. Graphene, with its large surface area and abundance of aromatic regions, is considered advantageous as SERS substrate. Combining graphene with metal nanomaterials considerably increases SERS signal intensity, thereby enhancing detection sensitivity. Therefore, this review emphasizes the significance of selecting graphene-metal nanohybrids as suitable SERS substrates for signal amplification. The detail understanding of the mechanism of graphene-metal hybrid in SERS based detection of early stage cancer is also presented. Furthermore, several examples demonstrated the application of graphene-metal hybrid nanomaterials in detecting biomarkers and cancer cell differentiation using SERS imaging.

In Situ Construction of Polypyrrole–Silver Composite Conductive Phase in High‐Performance Polyimide Sponge and Study of Sensing Behavior Under Microstress

Composites comprising conductive polymers and metal particles have garnered considerable interest in sensor technology due to their excellent electrical conductivity. However, producing controllable pressure sensors that retain high sensitivity under microstress remains challenging. Polyimide (PI) sponge exhibits excellent chemical and thermal stability and a porous structure that facilitates considerable deformation under low stress levels and results in good sensitivity to external forces. Herein, a conductive polymer–metal composite conductive phase, polypyrrole–silver (PPy–Ag), is directly fabricated on the PI surface through incipient network conformal growth. This method ensures that the PPy–Ag composite maintains optimal performance within its original temperature range, thereby enhancing detection sensitivity at low stress levels. The maximum conductivity of the fabricated PPy–Ag/PI composite sponge‐based flexible piezoresistive sensor is 2.42 × 10−4 S m−1, and the sensitivity is recorded at 16.31 kPa−1 within a stress range of 0–80 Pa. After undergoing 1000 compression cycles, the sensor exhibits commendable stability and reproducibility.

Development of an Improved Thiosulfate-Utilizing Denitrifying Bacteria-Based Ecotoxicity Test with High Detection Sensitivity and Reproducibility

Microorganism-based ecotoxicity assessment has been widely used as a reliable tool showing direct biochemical impacts of contaminants on ecosystems and the environment. The present study aimed at developing a thiosulfate-utilizing denitrifying bacteria (TUDB)-based ecotoxicity test with high detection sensitivity and favorable reproducibility. To achieve this goal, existing TUDB toxicity tests were improved by employing a pure culture of Thiobacillus thioparus ATCC 8158 and optimizing test conditions, particularly in terms of inoculated microbial biomass, incubating temperature, and operational pH. From control tests, it was found that 4 h is a sufficient processing time for TUDB test kits. As a result of optimization, 20 mg VSS/L of initial bacterial biomass, 25 °C of incubating temperature, and 6 of operational pH were determined as the most favorable test conditions, providing enhanced detection sensitivity and reproducibility. Under these optimal test conditions, I conducted toxicity tests for diverse toxic metals and obtained 0.65 ± 0.03, 1.09 ± 0.04, 1.21 ± 0.07, 0.13 ± 0.01, 0.56 ± 0.04, 1.42 ± 0.03, 0.98 ± 0.02, and 2.12 ± 0.05 mg/L of 4 h EC50 values for Ag+, As3+, Cd2+, Cr6+, Cu2+, Hg2+, Ni2+, and Pb2+, respectively. These EC50 values are substantially lower than those from earlier TUDB tests, demonstrating the high detection sensitivity of the current TUDB tests. Moreover, the present TUDB tests attained very low coefficient of variation (CV) values (1.6–6.3%) for the EC50, showing favorable reproducibility of the test methodology. In addition, the current TUDB toxicity tests offer numerous advantages for ecotoxicity assessment, including versatility for diverse test samples, no requirement for advanced equipment, and no distortion of end-point measurement. These refinements render the TUDB tests a favorable ecotoxicity assessment with enhanced sensitivity and reproducibility.

Distance-Based Fluorescent Immunosensor for Point-of-Care Test of Illegal Additives through the Gas-Producing Nanozyme.

The colorimetric point-of-care test (POCT) offers a rapid and efficient method for detecting specific targets in real samples. However, traditional colorimetric methods often rely on complex signal amplification techniques or electronic devices to enhance detection sensitivity, which can inadvertently increase both cost and time, thus contradicting the fundamental goals of visual detection methods. Here, we presented a distance-based fluorescent immunosensor that utilized a gas-producing nanozyme for continuous gas production reaction as a signal. Specifically, the SOM-ZIF-8@Pt nanozyme catalyzed the production of O2 from H2O2 to cause an obvious increase in the pressure within a sealed chamber, thus driving the production of H2S to quench the fluorescence of CsPbBr3 on the walls of the capillaries. Based on the competitive immunoassay, the fluorescence quenching lengths were relative with the concentration of aminopyrine in the range from 0.2 to 20 ng/L; thus, the fluorescent POCT-based homemade device was realized through the amplification of distance-based signals facilitated by the continuous gas production reaction. This strategy provides an effective way to realize POCT assays in resource-limited areas by transforming pressure variations into directly observable signals. Furthermore, distinguished by its high sensitivity, ease of operation, and portability, it also represents a significant advancement in biomedical diagnostics, particularly within home healthcare and clinical POCT.

Tailoring glassy carbon electrode surface with FeBiO3 for electrochemical detection of dinitrophenol isomers

ABSTRACT This study presents a simultaneous, rapid, and highly sensitive electrochemical detection of 2,4- and 2,5-dinitrophenol isomers using an iron bismuth oxide (FeBiO3)-modified glassy carbon electrode (GCE). The FeBiO3-modified GCE exhibited superior electrochemical performance over bare GCE, Bi2O3-modified GCE, and Fe2O3-modified GCE, as demonstrated by electrochemical impedance spectroscopy (EIS) with the potassium ferricyanide (Fe(CN6)3-/4-) standard. The synthesised electrocatalyst FeBiO3 exhibited strong absorption both in the visible and UV regions of the spectrum, attributed to band gap transitions and charge transfer transitions linked to its Bi2O3 and Fe2O3 components. The morphology and the structure of the FeBiO3 were characterised using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), while Fourier transform infrared spectroscopy (FTIR) was employed to analyse the functional groups attached to the surface of FeBiO3. Cyclic voltammetry (CV) clearly demonstrated an increased current and improved peak resolution for the reduction of 2,4- and 2,5-dinitrophenols at the FeBiO3/GCE, compared to the bare GCE. The mechanism shows that the reduction of 2,4- and 2,5-dinitrophenols occurs through interactions with the surface oxygen functional groups of FeBiO3, resulting in the stepwise reduction of their NO2 groups to hydroxyamino compounds and then to nitrosophenols. Using square wave voltammetry (SWV), the reduction peak currents were significantly improved, enhancing detection sensitivity beyond that reported in previous works. A linear range from 1 µM to 1 mm for the dinitrophenol isomers was established, with detection limits of 0.07 µM for 2,4-dinitrophenol and 0.09 µM for 2,5-dinitrophenol. The FeBiO3/GCE electrode showed interferences with mono-nitrophenols and mono-/di-chlorophenols in solution but maintained excellent long-term stability and reproducibility, allowing it to effectively detect dinitrophenol isomers in drinking water, tap water, and wastewater samples.

Towards Advancing Real-Time Railroad Inspection Using a Directional Eddy Current Probe

In the field of railroad safety, the effective detection of surface cracks is critical, necessitating reliable, high-speed, non-destructive testing (NDT) methods. This study introduces a hybrid Eddy Current Testing (ECT) probe, specifically engineered for railroad inspection, to address the common issue of “lift-off noise” due to varying distances between the probe and the test material. Unlike traditional ECT methods, this probe integrates transmit and differential receiver (Tx-dRx) coils, aiming to enhance detection sensitivity and minimise the lift-off impact. The study optimises ECT probes employing different transmitter coils, emphasising three main objectives: (a) quantitatively evaluating each probe using signal-to-noise ratio (SNR) and outlining a real-time data-processing algorithm based on SNR methodology; (b) exploring the frequency range proximal to the electrical resonance of the receiver coil; and (c) examining sensitivity variations across varying lift-off distances. The experimental outcomes indicate that the newly designed probe with a figure-8 shaped transmitter coil significantly improves sensitivity in detecting surface cracks on railroads. It achieves an impressive SNR exceeding 100 for defects with minimal dimensions of 1 mm in width and depth. The simulation results closely align with experimental findings, validating the investigation of the optimal operational frequency and lift-off distance for selected probe performance, which are determined to be 0.3 MHz and 1 mm, respectively. The realisation of this project would lead to notable advancements in enhancing railroad safety by improving the efficiency of crack detection.

DNA Origami Incorporated into Solid-State Nanopores Enables Enhanced Sensitivity for Precise Analysis of Protein Translocations.

The rapidly advancing field of nanotechnology is driving the development of precise sensing methods at the nanoscale, with solid-state nanopores emerging as promising tools for biomolecular sensing. This study investigates the increased sensitivity of solid-state nanopores achieved by integrating DNA origami structures, leading to the improved analysis of protein translocations. Using holo human serum transferrin (holo-hSTf) as a model protein, we compared hybrid nanopores incorporating DNA origami with open solid-state nanopores. Results show a significant enhancement in holo-hSTf detection sensitivity with DNA origami integration, suggesting a unique role of DNA interactions beyond confinement. This approach holds potential for ultrasensitive protein detection in biosensing applications, offering advancements in biomedical research and diagnostic tool development for diseases with low-abundance protein biomarkers. Further exploration of origami designs and nanopore configurations promises even greater sensitivity and versatility in the detection of a wider range of proteins, paving the way for advanced biosensing technologies.

Advancements in electrochemical immunosensors towards point-of-care detection of cardiac biomarkers.

Cardiovascular disease remains the leading cause of death worldwide, with mortality rates increasing annually. This underscores the urgent need for accurate diagnostic and monitoring tools. Electrochemical detection has emerged as a promising method for swiftly and precisely measuring specific biomarkers in bodily fluids. This approach is not only cost-effective and efficient compared to traditional clinical methods, but it can also be tailored to detect individual biomarkers, which makes it particularly well-suited for point-of-care (POC) applications. The ability to conduct testing at the point of care is crucial for timely interventions and personalized disease management, empowering healthcare providers to tailor treatment plans based on real-time biomarker data. Thanks to recent advancements in nanomaterials, we've seen significant progress in electrochemical detection, leading to the development of specialized rapid immunoassay systems. These systems utilize specific antibodies to target molecules, expanding the range of detectable biomarkers. This innovation has the potential to revolutionize the diagnosis and treatment of cardiovascular diseases by enhancing detection sensitivity and specificity. Ultimately, these advancements aim to improve patient outcomes by enabling earlier diagnosis, more precise monitoring, and personalized therapeutic interventions, which will contribute to more effective management of cardiovascular health globally.

Biocompatible Flash Chemiluminescent Assay Enabled by Sterically Hindered Spiro-Strained-Oxetanyl-1,2-Dioxetane.

Chemiluminescence is the emission of light that occurs as a result of a chemical reaction. Depending on the rate of chemiexcitation, light emission can occur as a long-lasting,glow-type reaction or a rapid, highly intense flash-type reaction. Assays using a flash-type mode of action provide enhanced detection sensitivity compared to those using a glow-type mode. Recently, our group discovered that applying spiro-strain to 1,2-dioxetanes significantly increases their chemiexcitation rate. However, further examination of the structure-activity relationships revealed that the spiro-strain severely compromises the chemical stability of the 1,2-dioxetanes. We hypothesized that a combination of spiro-strain, steric hindrance, and an electron-withdrawing effect, will result in a chemically stable spiro-strained dioxetane with an accelerated chemiexcitation rate. Indeed, spiro-fused tetramethyl-oxetanyl exhibited a 128-fold faster chemiexcitation rate compared to adamantyl while maintaining similar chemical stability, with a half-life of over 400 hours in PBS 7.4 buffer at room temperature. Turn-on probes composed of tetramethyl-oxetanyl spiro-dioxetane exhibited significantly improved chemical stability in bacterial and mammalian cell media compared to previously developed dioxetane probes fused to a cyclobutyl unit. The superior chemical stability enables a tetramethyl-oxetanyl dioxetane probe to detect β-galactosidase activity with enhanced sensitivity in E. coliassays and leucine aminopeptidase activity in cancer cells.

Development and validation of an LC-MS/MS method for the detection of sodium pentachlorophenolate residues on cutting boards.

The objective of this study was to develop and validate an automated solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the detection of sodium pentachlorophenolate (PCP-Na) residues on cutting boards. Given the potential hazards and environmental persistence of PCP-Na, a sensitive and reliable method is crucial for monitoring its residues in food contact materials to ensure consumer safety. Wood shavings from cutting boards were extracted using 10% methanol in water, followed by purification using an automated SPE system. The eluent was concentrated, reconstituted, and analyzed by UPLC-MS/MS. An isotope-labeled internal standard was used to mitigate matrix effects, enhancing detection sensitivity. The method was validated by assessing linearity, limit of detection (LOD), limit of quantification (LOQ), recovery rates, and relative standard deviations (RSDs) across various concentration levels. The method demonstrated excellent linearity over a concentration range of 0 to 100 μg/L with a regression equation of Y = 1.035X-0.7771 and an R² of 0.9996. The LOD and LOQ were determined to be 0.4 and 1.0 μg/kg, respectively. Recovery rates ranged from 71.75% to 96.50% with RSDs between 5.19% and 16.66%. When applied to 30 market cutting board samples, PCP-Na residues were detected in 50% of the samples, with concentrations ranging from 0 to 83,990 µg/kg. This study presents a robust UPLC-MS/MS method for the detection of PCP-Na on cutting boards, offering improved sensitivity and simplified sample preparation. The high detection rate in commercial samples underscores the need for stringent monitoring and regulatory measures to mitigate the exposure risk to consumers.

Synergistic signal amplification for HER2 biosensing using tetrahedral DNA nanostructures and 2D transition metal carbon/nitride@Au composites via ARGET ATRP

The rising incidence of breast cancer underscores the critical need for accurate and early detection methods, particularly for key biomarkers like human epidermal growth factor receptor 2 (HER2). Here, a synergistic signal amplification electrochemical biosensor was developed for HER2 detection that utilizes tetrahedral DNA nanostructures (TDN), 2D transition metal carbon/nitride@Au (MXene@Au) composites, and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Specifically, TDN serves as the substrate, with the aptamer anchored by the MXene@Au composite support matrix. This design facilitates the generation of electrochemical currents through the ARGET ATRP signal amplification strategy. The robustness and high affinity of TDN minimize surface effects on the electrode and enhance target binding. Additionally, the high conductivity of the MXene@Au composites improves the detection sensitivity of the biosensor. The use of the ARGET ATRP strategy further enhances detection sensitivity. The biosensor exhibits a wide detection range from 10 pg·mL−1 to 10 µg·mL−1 with a remarkable detection limit of 0.39 pg·mL−1, verified under optimal experimental conditions. The designed biosensor offers a significant advancement in the field of oncological diagnostics, providing a highly sensitive, low-cost, and simple method for early HER2 detection, thereby potentially improving treatment outcomes for breast cancer patients.

Simultaneous reflectance and fluorescence measurements for portable formaldehyde determination in milk using a multi-channel spectrometer sensor

This study introduces a novel optical method for formaldehyde determination in milk, based on the hypothesis that simultaneous reflectance and fluorescence measurements can enhance detection sensitivity compared to traditional methods. We aimed to address the challenge of accurately measuring low concentrations of formaldehyde in milk, a crucial issue for food safety. By employing a multi-channel spectrometer sensor and exploiting the reaction of formaldehyde with acetylacetone to form 3,5-diacetyl-1,4-dihydrolutidine (DDL), we measured reflectance of DDL at 415 nm and fluorescence at 515 nm. The method demonstrated linearity (0.1–4 mg L−1 for reflectance, 0.1–3 mg L−1 for fluorescence) with detection limits of 0.027 mg L−1 (reflectance) and 0.030 mg L−1 (fluorescence). We successfully determined formaldehyde in milk samples (46 to 114 μg L−1) and observed a 60 % reduction in formaldehyde concentrations. This research underscores the importance of heat treatment in ensuring food safety.

A novel triple-signal biosensor based on ZrFe-MOF@PtNPs for ultrasensitive aflatoxins detection

The development of more sensitive, stable, and portable biosensors is crucial for meeting the growing demands of diverse and complex detection environments. MOF-based nanozymes have emerged as excellent optical reporters, making them ideal signal donors for constructing multi-signal lateral flow immunoassays (LFIA). In this study, a ZrFe-MOF@PtNPs nanocomposite was synthesized by uniformly depositing platinum nanoparticles (PtNPs) onto the surface of ZrFe-MOFs using an impregnation-reduction method. The ZrFe-MOF@PtNPs exhibited broad absorption spectra, excellent peroxidase-like activity (SA = 21.77 U/mg), high solvent stability, and efficient antibody binding capability. A portable LFIA platform was developed based on ZrFe-MOF@PtNPs and a smartphone for the targeted detection of carcinogenic aflatoxins. This method enabled the readout of colorimetric, fluorescent, and catalytic signals, significantly enhancing detection sensitivity, ensuring result accuracy, and expanding the dynamic detection range. For aflatoxin M1, the calculation of the detection limit of the three signal modes reached as low as 0.0062 ng/mL, which is two orders of magnitude more sensitive than AuNPs-LFIA (0.1839 ng/mL). This study provides effective guidance for multifunctional modification of MOFs and serves as a reference for the application of MOF-based nanozymes in point-of-care biosensors.

Rapid Detection of Trace Organic Amines in Seawater: An Innovative Approach Using Photoelectron-Induced Chemical Ionization TOFMS with Online Derivatization and Dynamic Purging-Release Techniques.

Organic amines (OAs) have gained substantial interest in atmospheric chemistry due to their distinctive acid-base neutralization characteristics for secondary organic aerosols and new particle formation. To address the need for sensitive and online analysis of OAs, including dimethylamine (DMA), diethylamine (DEA), trimethylamine (TMA), and triethylamine (TEA), in seawater, a home-built photoelectron-induced chemical ionization TOFMS, coupled with online derivatization and dynamic purge-release apparatus, has been developed. Sodium hypochlorite is used to derivatize high-solubility DMA and DEA, substituting hydrogen atoms with chlorine atoms to obtain more volatile derivatives, [DMA-H + Cl] and [DEA-H + Cl]. Sodium carbonate is used to reduce the solubility of the OAs in solution to enhance detection sensitivity. Microbubbles generated from 250 to 300 mL/min of zero air at the gas-liquid interface efficiently transfer dissolved OAs into the gas phase. Water vapor in the purged gas is ionized by photoelectrons to form (H2O)n·H+, which ionizes OAs and their derivatives to produce characteristic ions [OAs + H]+ or [OAs-H + Cl]·H+ characteristic ion. After optimizing the experimental conditions, the limits of quantification (S/N = 10) of the four OAs including DMA, DEA, TMA, and TEA can be as low as 1.1 0.68, 0.85, and 0.49 nmol/L, respectively within a 5 min analysis time, using only 5 mL of seawater sample. This method enhances sensitivity by over 5-fold and reduces analysis time to 21.7%, respectively, compared with conventional methods. Subsequently, this method was successfully applied to quantify 15 seawater samples from 5 typical marine environments, which demonstrates its practicability and reliability for analysis of trace amines in seawater.

Ultrasensitive Detection of Trace Silver Ions Using MoS42--Intercalated LDH Nanosheets Enhanced SPR Sensor.

The widespread use of silver raises concerns about environmental and health risks, necessitating highly sensitive detection methods for trace silver ions (Ag+). Surface plasmon resonance (SPR) sensors offer benefits like label-free detection and rapid response, but their sensitivity for Ag+ detection is limited due to weak ion adsorption. Here, we developed an SPR sensor with MoS42--intercalated NiAl-layered double hydroxide (LDH) as the adsorption layer of Ag+ to enhance detection sensitivity. Our sensor achieves a sensitivity of 254.75 nm/μg/L and detects Ag+ at a low concentration of 2.8 pM, outperforming various existing sensors. It also shows excellent repeatability, long-term stability, and selectivity, proving effective in real-world environmental samples. This work advances high-performance SPR sensors for heavy metal ion detection.

A Visual Distance-Based Capillary Immunoassay Using Biomimetic Polymer Nanoparticles for Highly Sensitive and Specific C-Reactive Protein Quantification.

The low-cost daily monitoring of C-reactive protein (CRP) levels is crucial for screening acute inflammation or infections as well as managing chronic inflammatory diseases. In this study, we synthesized novel 2-Methacryloyloxy ethyl phosphorylcholine (MPC)-based biomimetic nanoparticles with a large surface area to develop a visual CRP-quantification assay using affordable glass capillaries. The PMPC nanoparticles, synthesized via reflux precipitation polymerization, demonstrated multivalent binding capabilities, enabling rapid and specific CRP capture. In the presence of CRP, PMPC nanoparticles formed sandwich structures with magnetic nanoparticles functionalized with CRP antibodies, thereby enhancing detection sensitivity and specificity. These sandwich complexes were magnetically accumulated into visible and quantifiable stacks within the glass capillaries, allowing for the rapid, sensitive, and specific quantification of CRP concentrations with a detection limit of 57.5 pg/mL and a range spanning from 0 to 5000 ng/mL. The proposed visual distance-based capillary biosensor shows great potential in routine clinical diagnosis as well as point-of-care testing (POCT) in resource-limited settings.

Carbon‐Based Biosensor in Point of Care Setting

AbstractIn medical diagnosis, detecting disease biomarkers at ultra‐low concentrations is vital. Point‐of‐care (POC) diagnostics require rapid detection, live monitoring, high sensitivity, low detection threshold, and cost‐effectiveness. Carbon‐based nanomaterials (CBNs) are promising due to their large surface‐to‐volume ratio, conductivity, biocompatibility, and stability, making them ideal for biosensors. Recent advancements in CBN applications, including biosensing, drug delivery, and cancer therapy, highlight their potential in enhancing detection sensitivity and specificity. Electrochemical sensors and biosensor platforms using carbon nanocomposites are pivotal in diagnostics. This review explores the current state and future challenges of CBN integration in POC settings, envisioning a transformative impact on healthcare diagnostics and therapeutics.

Solvent Effects in Hyperpolarization of 15N Nuclei in [15N3]Metronidazole and [15N3]Nimorazole Antibiotics via SABRE‐SHEATH**

AbstractMetronidazole and nimorazole are antibiotics of a nitroimidazole group which also may be potentially utilized as hypoxia radiosensitizers for the treatment of cancerous tumors. Hyperpolarization of 15N nuclei in these compounds using SABRE‐SHEATH (Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei) approach provides dramatic enhancement of detection sensitivity of these analytes using magnetic resonance spectroscopy and imaging. Methanol‐d4 is conventionally employed as a solvent in SABRE hyperpolarization process. Herein, we investigate SABRE‐SHEATH hyperpolarization of isotopically labeled [15N3]metronidazole and [15N3]nimorazole in nondeuterated methanol and ethanol solvents. Optimization of such hyperpolarization parameters as polarization transfer magnetic field, temperature, parahydrogen flow rate and pressure allowed us to obtain an average 15N polarization of up to 7.2–7.4 % for both substrates. The highest 15N polarizations were observed in methanol‐d4 for [15N3]metronidazole and in ethanol for [15N3]nimorazole. At a clinically relevant magnetic field of 1.4 T the 15N nuclei of these substrates possess long characteristic hyperpolarization lifetimes (T1) of ca. 1 to ca. 7 min. This study represents a major step toward SABRE in more biocompatible solvents, such as ethanol, and also paves the way for future utilization of these hyperpolarized nitroimidazoles as molecular contrast agents for MRI visualization of tumors.