Sensors & diagnostics最新文献

We developed a compact image-based flow cytometry system that combines acoustic focusing with machine learning-driven image analysis. The system enables rapid detection of stained CD4 and CD8 cells flowing on an acoustically defined focal plane, without the need for hydrodynamic focusing. This design allows for a compact configuration while maintaining reliable performance and reduced complexity, making the system suitable for both clinical diagnostics and point-of-care applications.

Despite the increased availability of low-cost and effective treatments for tuberculosis (TB), ∼1 million people continue to die from TB-related symptoms annually. One major challenge limiting the effectiveness of TB treatment is delays in diagnosis, largely due to current detection methods requiring either weeks of culture time or complex processing steps that cannot be performed at the point-of-care. Thus, there is a need for alternative methods that are easier to use yet still effective in providing an accurate TB diagnosis. This work investigates the feasibility of using high-wavenumber Raman spectroscopy to detect the presence of the causative agent of TB, Mycobacterium tuberculosis, in human saliva. To accomplish this, raw saliva was collected from healthy participants and inoculated with a fixed, physiologically relevant, concentration of bacteria (10⁶ CFU mL⁻¹) and concentrated into a pellet. The samples were measured using Raman spectroscopy and analyzed with a spectral unmixing approach to determine the relative biochemical composition. The presence of M. tuberculosis resulted in a significant increase in the lipid signal of saliva pellets containing the spiked bacteria, with a median percent increase of 423.6% as compared to the control samples. Control experiments using Streptococcus mutans, a common oral bacterium, only resulted in a slight increase of 9.8%. Additionally, using linear regression analysis, a predictive relationship was found between the Raman lipid fractions of the raw saliva and the control saliva pellets. Using the 95% prediction interval of this relationship as a classification threshold, the presence of M. tuberculosis was accurately determined for all samples with an overall training accuracy of 98.5% and a cross-validation accuracy of 100%. These results showcase the potential of high-wavenumber Raman spectroscopy as a reagent-free method of detecting M. tuberculosis in saliva samples.

Electrochemical gas sensors have attracted significant attention due to their high sensitivity and selectivity in detecting various gases. Recent advancements in microelectronics, materials science and computational technologies have driven the development of smart electrochemical gas sensors, enhancing their functionality with improved miniaturization, real-time data analysis, and remote monitoring capabilities. Furthermore, the integration of the internet of things, self-powered technologies and machine learning has expanded the potential of these sensors, enabling smart healthcare systems to adapt to complex and dynamic environments just as humans do. This paper reviews the basic sensing mechanisms, detection methods, recent developments of three types of electrochemical gas sensors and the related fabrication techniques. In addition, we further review their applications in three fields including air monitoring, breath analysis and microfluidic integration. Finally, current challenges, limitations, and future prospects are addressed, emphasizing the need for improved stability, selectivity, and energy efficiency to develop the next generation of electrochemical gas sensors.

Detecting antibodies (Abs) is essential for assessing acquired immunity to infectious diseases, particularly following vaccination or prior infection. However, conventional serological tests often suffer from several limitations, including labor-intensive preparation, the need for specialized biosafety facilities, and lengthy processing times. Moreover, they provide only qualitative results with limited specificity. While homogeneous serological assays offer a simpler approach to detect Abs in biological samples, their sensitivity is often compromised by high background interference. In this study, we present a time-resolved fluorescence energy transfer (TR-FRET) assay for detecting infectious disease Abs in human sera. Our assay demonstrates high sensitivity in distinguishing between an antigen and its specific antibody, with no detectable upper limit of detection or prozone effect. It is universally applicable to various antigen–antibody complexes including SARS-CoV-2 and influenza, delivers accurate results within 15 minutes, and effectively mitigates background noise from human specimens. The development of this highly accurate immunoassay will enhance serological testing, making it faster, more reliable, and suitable for point-of-care settings.

Lab-on-a-chip (LoC) devices represent systems where microfluidics converges with state-of-the-art technologies, playing an immense role in reshaping clinical and biomedical sciences. This review deeply explores the design principles and diverse applications of LoC devices, ranging from point-of-care diagnostics to entire human-on-a-chip devices. Notably, LoC devices showcase remarkable adaptability and versatility. While LoC devices offer many advantages over conventional laboratory assessment methodologies including small sample size, reduced assay time and cost-effectiveness, the field faces many challenges in terms of designing, standardizing and large-scale production of the devices. In the end, while shedding light on how LoC devices stand at the forefront of the innovative technologies in the field of clinical and biomedical sciences, the review also emphasizes on their applications and integration with state-of-the-art technologies like AI and machine learning, along with their limitations and the further necessary developments for their widespread acceptance.

Theranostic clinical translation has been hindered by the lack of analytical tools facilitating interrogation. Here we report the detection of a chemotherapeutic agent, gemcitabine, released via heat trigger, from a hybrid iron oxide–gold theranostic nanoparticle surface in vitro in pancreatic cancer cells by electrochemiluminescence directly addressing this analytical gap.

The specific detection of Cu²⁺ and BF₃ provided the basis for the design of the distinctive dual-sensing chemosensor, 2-(benzo[d]thiazol-2-yl)-6-(1,4,5-triphenyl-1H-imidazol-2-yl) phenol (SP26). SP26 was synthesized successfully using a multi-step process, with its identity confirmed by NMR spectroscopy and HR-MS analysis. The studies were conducted in an 8 : 2 THF/water mixture. The ligand was solubilized in THF/water, whereas the cation salts were dissolved in water. The absorption measurements indicated no detection of cations other than Cu²⁺. The emission experiments revealed that the optical selectivity for the Cu²⁺ ion leads to a reduction in emission intensity. Likewise, with BF₃, the emission intensity diminishes with the bathochromic shift. The limit of detection (LoD) for Cu²⁺ is 381 pM, and for BF₃ it is 307 pM. After adding BF₃ and Cu²⁺ to SP26, the complex formation was so quick that it happened within a fraction of a second. Triethylamine (TEA) was used for BF₃, and ethylenediamine tetraacetic acid (EDTA) for Cu²⁺ to determine the reversibility. FT-IR, HR-MS, Job's plot, DFT, and ¹H NMR titration analyses confirmed that chemosensor SP26 was bound to Cu²⁺ and BF₃. Paper test strips showed the potential of the chemosensor SP26 for the environmental detection of Cu²⁺ and BF₃. The quantitative analysis of Cu²⁺ was examined with environmental water samples.

The development of reliable and cost-effective electrochemical sensors for hydrogen peroxide (H₂O₂) monitoring is crucial in biomedical diagnostics, especially in early disease diagnosis. Herein, we prudently synthesized an acid-functionalized COOH–Ti₃C₂T_x MXene, onto which a toluidine blue (TB) redox mediator was covalently immobilized and employed for the distinctive determination of H₂O₂. The synthesized COOH–Ti₃C₂T_x MXene is coated over a glassy carbon electrode (GCE), followed by the covalent immobilization of the electroactive TB dye through the N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) coupling reaction. This in turn results in the firm anchoring of the TB dye by establishing a stable amide linkage between the –COOH group of COOH–Ti₃C₂T_x and the free –NH₂ group of TB. Thus, the obtained TB/COOH–Ti₃C₂T_x/GCE sensor demonstrates an excellent electrocatalytic response for H₂O₂ determination over a broad linear range of 5 μM to 100 μM and 100 μM to 1.1 mM with a high sensitivity of 0.61 μA μM⁻¹ cm⁻² and a low detection limit of 1.5 μM. Notably, the fabricated electrode demonstrated exceptional stability and reproducibility as well as high selectivity and sensitivity in the detection of H₂O₂. Furthermore, the developed sensor showed very good recovery towards the detection of H₂O₂ in milk and serum samples. The attained analytical performance is attributed to the improved electrical wiring between the TB mediator and the conductive MXene platform.

Cystic fibrosis (CF) arises from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Monitoring I⁻ transport serves as a critical approach for evaluating CFTR function in live cells, providing a foundation for the development of diagnostic tools and therapeutic treatments. Here, we report an iridium(III) complex (I-Sense) for the selective and pH-independent imaging of intracellular I⁻. By tracking cellular iodide I⁻ uptake, I-Sense facilitates the evaluation of CFTR activity in live cells, providing a valuable tool for the functional characterization of CFTR activity.

Organic thin-film transistors (OTFTs) have emerged as a promising platform for gas sensing applications due to their low-power operation, room-temperature sensitivity, and structural tunability. In this work, we investigate the effect of gate voltage (V_GS) on the ammonia (NH₃) sensing performance of OTFT-based sensors using copper phthalocyanine (CuPc, p-type) and its fluorinated derivative (F₁₆CuPc, n-type) as the active layers for the first time. Devices were exposed to NH₃ concentrations ranging from 0 to 100 ppm, and their electrical responses were monitored across different V_GS values. Results demonstrate that modulating V_GS significantly impacts key sensing parameters, including relative response (RR), sensitivity, limit of detection (LOD), and response/recovery kinetics. The lowest LODs achieved were 0.4 ppm for CuPc and 0.21 ppm for F₁₆CuPc. These findings highlight the potential of V_GS modulation as a powerful strategy to optimize OTFT sensor performance and provide a new dimension of tunability for gas detection technologies at room temperature.