Sensors & diagnostics最新文献

Correction for ‘Highly sensitive urine glucose detection with graphene field-effect transistors functionalized with electropolymerized nanofilms’ by Gonzalo E. Fenoy et al., Sens. Diagn., 2022, 1, 139–148, https://doi.org/10.1039/D1SD00007A.

Metabolomics allows the analysis of metabolites in biological samples to identify biomarkers associated with metabolic processes, and among these volatile organic compounds (VOCs) have emerged as a significant component in non-invasive diagnostics playing a crucial role in understanding physiological and pathological conditions. The changes in metabolic pathways that occur in biological systems during disease states result in the generation of VOCs as end products or intermediate products. These are then transported to the lungs via the circulatory system and presented into breath at the alveolar membrane. This direct link between metabolic changes and exhaled VOCs has driven growing interest in breathomics, a non-invasive approach to disease diagnosis and monitoring. Among numerous gas sensing technologies that have been explored, electrochemical sensors have demonstrated high sensitivity, cost-effectiveness, real-time monitoring, and miniaturization capabilities. In this work, we have developed a ferrocene (Fc) encapsulated zeolitic imidazole framework −8 (ZIF-8) for the detection of 4 physiologically relevant VOCs: ethanol, isopropanol, acetic acid, acetone, utilizing chronoamperometry as the transduction principle. The material characterization was performed using X-ray photoelectron spectroscopy, powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray analysis, and thermogravimetric analysis to confirm the morphological properties of Fc@ZIF-8. The dose-dependent response curves were established for each VOC, demonstrating linearity and the sensor's detection capabilities. Additionally, the sensor's accuracy was confirmed with spike and recovery experiments, achieving recovery rates within the CLSI guideline range of 80–120%.

Correction for ‘3D-printed electrochemical cells for multi-point aptamer-based drug measurements’ by John Mack et al., Sens. Diagn., 2024, 3, 1533–1541, https://doi.org/10.1039/D4SD00192C.

For several years now, the development of rapid, sensitive, portable and inexpensive early diagnosis techniques has been the focus of increasing attention in the healthcare field, for both primary care and emergency medicine. We have previously demonstrated the proof-of-concept of a patented microfluidic biochip integrating a giant magnetoresistance (GMR)-based sensor, placed on either side of the channel, allowing for the one-by-one dynamic detection of single magnetically labeled biological targets, in a continuous flow mode. In this article, we implemented this two-stage GMR sensor to improve the readiness level of this technology and move towards point-of-care (POC) analysis. We used semi-complex culture medium samples spiked with a murine cancer cell line, pre-labeled with functionalized magnetic particles, to evaluate the biochip performances in detail. The quantitative detection of target cells in low concentrated samples was achieved, with a sensitivity of 5 × 10² cells per mL at a 2 mL per hour flow rate and good specificity, even after addition of irrelevant cells to the sample. Finally, we demonstrated that these performances are competitive with existing techniques such as ELISA tests and flow cytometry analysis, paving the way for new GMR-based POC tests.

Breast cancer occurs when cells grow abnormally and form tumors. It is currently one of the most prevalent cancers in women, and it is known to cause serious detrimental effects if not detected on time. Thus, early detection and screening may tremendously contribute to a patient's medical treatment. The boom in cancer diagnostics resulted from the demand to overcome the limitations of bulky and time-consuming conventional detection methods. The new and advanced methods are simpler, faster and easily deployable. This review elucidates various techniques used for breast cancer detection, which include optical, electrochemical, mechanical, electrical, thermal and color- and breath-based methods. An overview of different techniques is presented with additional information related to the available commercial options. This review also presents the integration of artificial intelligence and Internet of Things into futuristic diagnostic techniques. The unmet needs and challenges are also discussed. Overall, this review is a comprehensive package for researchers who want to dive into the advances of breast cancer diagnostics.

Screen printing and inkjet printing are attractive processes to produce low-cost and mass producible electroanalytical sensors. Despite important advances in the field, obtaining a printed electrochemical reference element that satisfies analytical requirements has not yet been realized satisfactorily. This paper investigates the use of screen printing and inkjet printing to produce a self-contained, all-solid state reference element that can be integrated with a wide range of electroanalytical sensing principles. The principle relies on a silver/silver iodide element that self-generates its potential by the application of a so-called pulstrode protocol. Specifically, a defined quantity of iodide is released by a short cathodic current pulse, and the reference potential defined by the released iodide is subsequently recorded at zero current. Both screen and inkjet-printed reference electrodes are fabricated and characterized, and the methodology optimized and assessed. As an application example, a single-point calibration method is used to quantify ions in undiluted filtered urine samples by potentiometry. The screen-printing approach was less successful owing to the low purity of the silver ink used. The inkjet printing approach allowed one to quantify chloride and sodium in urine. Using a conventional silver/silver chloride reference electrode as standard, relative errors of respectively 7.7 and 14.1% for chloride and sodium were obtained. While the approach would benefit from further optimization for long term applications, especially the use of high purity silver inks, it is a promising strategy for the realization of fully integrated all-solid-state microfabricated sensing systems.

A bimodal sensor, (E)-2-(4-(diphenylamino)styryl)-1-methylquinolin-1-ium (DSM), was designed and synthesized for the simultaneous fluorescence turn-on detection of Ni²⁺ ion and biomolecules such as ct-DNA, BSA, and ovalbumin. Due to its distinct size and steric properties, DSM exhibits different binding modes when interacting with Ni²⁺ and DNA/proteins. The probe DSM possesses dual functionalities, allowing it to selectively detect Ni²⁺ at one binding site while interacting with ct-DNA, BSA, and ovalbumin at another. Thus, interactions of DSM with Ni²⁺ result in fluorescence enhancement at 377 nm and 400 nm, with a detection limit of 1.53 μM and binding constant of 1.2 × 10⁶ M⁻¹. Moreover, the binding of DSM with Ni²⁺ has been demonstrated via UV-vis, mass spectra, Jobs plots and DFT analysis. Conversely, binding of DSM with ct-DNA, ovalbumin and BSA led to an increase in the fluorescence at 425 nm and 435 nm, respectively, with the detection limit at micromolar (ct-DNA) and nanomolar (BSA and ovalbumin) levels. These interactions have been validated through UV-vis spectroscopy, fluorescence studies, and molecular docking analysis. Thus, this study underscores the potential of DSM as a versatile tool for simultaneous detection of both metal ions and biomolecules with a unique bimodal approach.

Alcohol is one of the most widespread mind-affecting substances increasing the internal feeling of happiness, euphoria, conviviality and pleasance, but the improperly distilled (adulterated) beverages containing methanol pose risk to the human health. Measures for preventing the intoxication with counterfeit alcohol comprise point-of-use analysis of the alcohol via portable metal-oxide devices, liquid crystal-based detectors and spectrometric sensors with limited effectiveness due to periodic clogging of the separation column, uncertainties induced by the color of emitted light or unstable signal caused by the different optical transparencies of alcohol containers. Contemporary electronics may provide sustainable solutions to these problems by launching miniature metal–phenolic film-coated quartz crystal microbalances (MPF-QCMs) for selective detection of methanol in spirits; however, the effect of surface profile of the sorptive layer on the sensor response of these devices is unknown. We eliminate this knowledge gap by spin coating metal–phenolic films with different morphology, chemistry, wettability and thickness on the surface of six 5 MHz QCMs and subjecting them to the saturated vapor of methanol, ethanol, isopropanol, water, petroleum ether and ammonium hydroxide. The execution of over hundred experiments shows that the MPF-QCMs discriminate the chemical analytes in a repeatable and reproducible manner depending on their molecular size and acidity, and the morphochemical peculiarities of the solid surface, facilitating the registration of methanol fractions up to three orders of magnitude below the admissible concentrations in spirits. Our results provide scientific advance that has potential to address the global challenge related to the consumption of denatured alcohol.

Electroanalytical methods which can aid in the selective quantitation of saccharides such as the sialic acid N-acetyl-D-neuraminic acid (Neu5Ac) are very attractive due to their significance in a wealth of human diseases and food/nutritional products. Using cyclic voltammetry, boronic acid–diol recognition based on a redox indicator displacement assay (RIDA) strategy was exploited for non-enzymatic comparative electroanalysis of Neu5Ac vs. fructose using the redox active reporter Alizarin Red S (ARS). The concept has its foundation in the classical competition between an analyte and an indicator (ARS) for the same binding site on a host (boronic acid) molecule. The pH dependent assay employed first-time use of (thiophen-3-yl)boronic acid (TBA) as heterocyclic chemoreceptor. Electrochemistry of ARS in equilibrium with TBA resulted in proton coupled redox processes at −0.48 V (free ARS), −0.29 V (ARS–TBA boronate ester) and +0.51 V vs. Ag|AgCl (free ARS) correlating with ARS concentration in the TBA–ARS equilibrium or in competition equilibrium with a sugar species. Saccharide driven boronic acid displacement resulted in the reinstatement of the free ARS redox processes, forming the basis for the analytical signal. Voltammetry and optical investigations established the optimum conditions for Neu5Ac measurement relative to competing species such as fructose, enabling pH tunable ratiometric quantitation over the range 1–10 mM Neu5Ac (0.1 M sodium acetate buffer pH 5.6) with sensitivity 0.119 ± 0.009 μA mM⁻¹ and LOD 0.63 mM (using differential pulse voltammetry). The homogeneous studies paved the way for film formation and preliminary displacement testing when ARS was surface confined within a chitosan biopolymer layer on a glassy carbon electrode.

Multimodal optical resonators can integrate multiple sensing functions on a single device by assigning specific tasks to different modes. To facilitate such expanded functionality, this study demonstrates a photopatterning approach in which resonantly-amplified light within whispering gallery mode (WGM) sensors is used to direct chemical modification of the corresponding surface region addressed by the mode. A Ru(II) metallo–organic complex containing a caged aminopropyltriethoxysilane (APTES) moiety, [Ru(tpy)(biq)(APTES)](PF₆)₂, was synthesized and applied as a covalently immobilized layer to solid supports to be patterned, including spheroidal silica WGM resonators. Exciting a mode caused the area exposed to the light to be deprotected, leaving behind a pattern of reactive amine groups available for further derivatization. A two-photon deprotection process enabled the use of near-IR sources for patterning. The photopatterning technique was applied to self-referenced measurements, in which signals from two modes, a sensing and a reference mode, were used to detect specific binding of avidin against a much larger background of nonspecific adsorption. This was accomplished by patterning the sensing mode with biotin to specifically bind avidin while the reference mode tracked nonspecific adsorption.