Sensing and Bio-Sensing Research最新文献

An innovative three-electrode system was developed for electrochemical analysis, aiming to overcome the limitations of conventional approaches. The system incorporates a glassy carbon rod as the working electrode, platinum wire as the counter electrode, and silver wire as the quasi-reference electrode that are positioned within an epoxy resin substrate. The advantages of this type of three-electrode system include the possibility of sample analysis in both drop mode and when immersed in the solution, low manufacturing cost, reduction of chemical consumption, no need for special maintenance protocols, no requirement for stand, absence of liquid junction potential (due to the direct contact of the reference electrode with the solution), usability for on-site analysis, and usability for non-aqueous solutions.

To check the efficiency of this electrode, cyclic voltammetry technique was used. Also, for direct comparison of PTE with conventional three-electrode system and screen-printed electrode (SPE), current density was used instead of peak current. According to the results, PTE system shows more peak current for the same surface area of the working electrode compared to other systems, which shows the high efficiency of the proposed system for electrochemical analysis. Acetaminophen (ACT) was chosen in order to investigate the ability to measure an analyte with PTE using differential pulse voltammetry (DPV). The linear range was obtained from 29.12 μM to 609.37 μM with a detection limit (LOD) 20.22 μM. Also, PTE was used to measure ACT in tablet as real sample.

Infectious diseases in farm animals triggered by pathogenic microorganisms affect the health and well-being of livestock and human populations. Pathogen detection is an important step for the successful diagnosis, treatment and control of infectious diseases in animals. Pathogens that persist in the poultry and livestock industries can be responsible for more than 70% of emerging infections. Thus, rapid diagnostic tools are extremely important. In recent years, nanotechnology has emerged as a great opportunity to tackle this challenge and to develop fast, accurate and economical diagnostics for the detection of pathogens. Various nanostructures, due to the presence of unique characteristics shown in nanomaterials, have already been applied in biodiagnostics to detect specific molecular targets, including pathogen detection. In this context, this review focuses on the application, role and challenges of nanosensors in detecting disease-causing pathogens in agriculture. Several nanostructures are investigated for their utility in providing innovative solutions for pathogen detection in farm animals. This comprehensive examination seeks to unravel the intricate nanosensors landscape, shedding some light on their role in advancing diagnostic capabilities within the agricultural domain. By elucidating the challenges inherent in their application, the review contributes to the ongoing discourse on harnessing nanotechnology for the detection and management of infectious diseases in livestock, ultimately paving the way for developments in veterinary diagnostics.

The technology of surface plasmon resonance (SPR) is widely recognized and valued for its ability to rapidly and sensitively investigate biomolecular interactivities in real-time. Herein, we numerically investigate the collective influence of metal/ transition metal dichalcogenide (TMDC)/halide perovskite (HP)/2D carbon (C) and phosphorus (P) allotropes on the functionality of an SPR biosensor deploying Kretschmann configuration. The incident light wavelength is held constant at 633 nm, and radiative properties of the hybrid structure are determined using the attenuated total reflection and transfer matrix techniques. Crucial performance metrics such as quality factor (QF), figure of merit (FoM), sensitivity, and detection accuracy are calculated. The comparison is conducted and evaluated against the current literature using performance outcomes in terms of several prisms such as BK7, BAK1, BAF10, SF5, SF10, SF11, 2S2G, CaF₂, and CsF, several TMDCs such as WS₂, MoS₂, WSe₂, MoSe₂, and PtSe₂, several HPs such as CsPbI₃, KSnI₃, CsSnI₃, and FASnI₃, and 2D C/P allotropes such as Graphene, MXene, Black phosphorene (BP), and Blue phosphorene (BlueP) in order to search optimum parameters, and then we implement the best one in each layer of this biosensor design. It is noticed that the SPR heterostructure based on BAK1 prism, plasmonic metal Ag, tungsten disulfide (WS₂) TMDC, formamidinium tin iodide (FASnI₃) HP and 2D BP exhibits outstanding performance with regard to sensor performance characteristics. The observed FoM and sensitivity are 48.2/RIU and 402°/RIU, respectively. The investigation of the electric field distribution within this biosensor along the normal to the interface is also conducted using the finite difference time domain (FDTD) approach to demonstrate the unique contribution of FASnI₃. The findings presented in this study are anticipated to play a key role in the improvement of plasmonic resonance-based biosensing domains like DNA hybridization or formalin detection by employing halide perovskite as an additional layer in SPR biosensors.

Manufacturing technology of ion-selective electrodes (ISEs) for pH measurements is presented. Plasticized polyurethane membranes with tridodecylamine as a pH-selective ionophore were used as receptor layer, whereas electrodes printed with graphene nanoplatelets paste served as transducers. For preliminary experiments, sensors with screen-printed transducers and pH-selective membranes deposited manually or by direct-ink writing, were employed. However, the use of aerosol-jet printing (AJP) technique for the production of transducer as well as deposition of pH-selective polymeric membrane allowed substantial miniaturization of the sensors, leading to low-cost, automated fabrication of millimeter-scale ISEs. The pH sensors were printed on thermoplastic polyurethane (TPU) or polyethylene terephthalate (PET) substrate, the issues of compatibility of membrane and substrate materials were addressed. The average membrane thickness for the ISEs was 225.2 ± 8.0 μm with an additional 20 μm average thickness of other underlying printed layers. The planar dimensions of ISEs were 300 μm (width) by 2 mm, presenting an opportunity for even further miniaturization. Sensors fully printed with the AJP technique yielded a potentiometric response of −53.48 ± 4.26 mV/pH (N = 69) for PET substrate and − 46.71 ± 10.23 mV/pH (N = 66) for TPU substrate. Presented results are important for developing a fully operational electronic tattoo suitable for large-scale manufacturing.

Early detection of prostate cancer, the second main cause of death in men, with robust assay platforms by using the appropriate biomarkers is of great importance for diagnosis and follow-up of disease under treatment. The aim of this research is to investigate how novel TiS₃ nanoribbons can be used as a channel material in the microfluidic electrolyte-gated field-effect transistor (FET), with the goal of developing a label-free immunosensor for the sensitive, selective, and rapid detection of PSA as a cancer marker in both PBS and human serum samples. To create an active channel material, the TiS₃ nanoribbons were deposited onto the FET surface through a drop-casting process, and the surface of the channel was subsequently modified with an anti-PSA monoclonal antibody. The electrical properties of the microfluidic electrolyte-gated TiS₃ nanoribbon-based FET were characterized, and the results showed that it exhibited a depletion-mode n-type behavior with a field-effect mobility of 2.3 × 10⁻³ cm²/Vs, an I_on/I_off current ratio of 4.12, and a subthreshold swing (SS) of 914.1 mV/decade. As the concentration of PSA increased from 0.1 fg/mL to 10 pg/mL, there was a corresponding increase in the drain current with a high sensitivity of 2.2665 nA/decade and a detection limit of 0.04 fg/mL. Integrating the electrolyte-gated FET with the microfluidic channel resulted in improved performance of the microfluidic electrolyte-gated FET immunosensor. The combination of these two components led to better control and delivery of small sample volumes to the surface of the electrolyte-gated FET, which improved the repeatability of the obtained data. Based on the results obtained from the microfluidic immunosensor, it can be inferred that the developed platform has the potential to be an excellent candidate for point-of-care cancer diagnosis and therapeutic monitoring.

This study reports the determination of Tinidazole (TDL) using a modified glassy carbon electrode, poly(bis(2,2′-bipyridine)diresorcinateruthenium(III) chloride) (poly(BBPDRRuC)/GCE) by a newly synthesized mixed ligand complex, bis-(2,2′-bipyridine)diresorcinateruthenium(III) chloride(BBPDRRuC). Electrochemical impedance spectroscopy (EIS) and cyclic voltamettry (CV) results demonstrated modification of the surface of the electrode by a conductive, and electroactive polymer film leading to an enhanced effective electrode surface area and their electrocatalytic role. Appearance of an irreversible reductive peak at much reduced potential with four folds current enhancement at poly(BBPDRRuC)/GCE showed the catalytic effect of the modifier by reduction of TDL. Square wave voltammetry current response of poly(BBPDRRuC)/GCE showed linear dependence on concentration of TDL in the range 10⁻⁸˗ 3.0 × 10⁻⁴ M with LoD and LoQ of 2.5 nM, and 8.2 nM, respectively. The TDL level in the studied tablet brands were in the range 96.6–101.1% of their labeled values. Spike recovery results in tablet, and human blood serum samples were in the range 98.3˗100.4%, and 98.85 ˗ 99.89%, respectively, and interference recovery results with <4.5% error. The developed method required a simple electrode modification step, a relatively chip, an easily available and non-toxic modifier, provides the least LoD, and reasonably wider linear dynamic range, and had excellent performance for the determination of TDL in tablet formulation and serum samples as compared with recently reported voltammetric methods.

Among the non-destructive techniques capable of obtaining information on biological systems even in vivo, terahertz-based techniques are emerging due to their specificity to the water content, which can represent an important indicator of the presence of microorganisms and, in general, of the health status, particularly in plants. Nevertheless, the analysis of the extracted data (especially for images) and the exploitation of the potential of the technique for the study of the complex phenomena that occur in living tissues are still almost unexplored fields. In this work, the hydration status of leaves both in vivo and ex vivo was monitored continuously and non-destructively by acquiring videos in the sub-terahertz range through a portable imaging system. A model for describing the water flow in space and time in the midvein of a leaf is obtained which is suitable for the analysis of the data extracted from the portable sub-terahertz imaging system. These results show that terahertz-based technology can be used to study biological phenomena even in vivo; moreover, they pave the way for the introduction of a general method for the analysis of terahertz data based on surface fits in space and in time as well.

Several studies have demonstrated that Ag₂S QDs are promising near-infrared II-emitting nanoprobes. They Ag₂S QDs can be used in the fields of bio-imaging, fluorescence detection and photodetectors. In this work, we achieved the first successful construction of a dual-input logic gate IMPLICATION gate based on the specific detection of Fe³⁺ by silver sulfide quantum dots and the reduction of Fe³⁺ by ascorbic acid. The Ag₂S QDs were successfully prepared from glutathione and silver nitrate and characterized by fluorescence spectroscopy analysis, XPS analysis, and transmission electron microscopy TEM analysis. The prepared Ag₂S QDs can achieve selective detection of Fe³⁺ with a detection limit of LOD of 0.15 mM. This work provides a new method for the detection of Fe³⁺.

This study introduces a dual-core photonic crystal fiber incorporating a highly responsive plasmonic refractive index (RI) sensor. The performance of the RI sensor is evaluated based on amplitude sensitivity, wavelength resolution, wavelength sensitivity, and the linearity of the resonance wavelength. Employing the finite element technique (FEM), a numerical analysis of the proposed design is conducted. Results indicate that employing the amplitude interrogation method yields a peak amplitude sensitivity of 605.82 RIU⁻¹ for y-polarization. Furthermore, the wavelength interrogation approach for y-polarized modes demonstrates a maximum wavelength sensitivity of approximately 17,000 nm/RIU and a maximum wavelength resolution of 5.88 × 10⁻⁶ RIU. The proposed sensor exhibits a figure of merit of approximately 298 and effectively responds to refractive index variations within the range of 1.28 to 1.40. These promising outcomes, coupled with the broad sensing range, establish the suggested sensor as a promising candidate for the detection of organic chemical solutions.

The application of a recombination sensor for real-time detection of Lactate Dehydrogenase (LDH) activities has been demonstrated. LDH activity in biological fluids, particularly in blood serum, is a critical diagnostic indicator of human health. Therefore, the development of methods for monitoring it remains a crucial task in modern bioengineering. The parameter directly measured in real-time is the photocurrent through a deep-barrier structure under light illumination from the region of strong optical absorption in silicon. The detection of enzyme presence can be achieved because the flow of the dehydrogenase reaction (in the presence of LDH activation) is accompanied by changes in charge at the system's interface. Such a change in the effective charge of the reactants can be detected through the amplitude of the sensor structure's photocurrent. The main factor in this approach is the influence on the recombination center parameters at the interface. It has been shown that the combined use of modulated signal illumination and constant illumination allows obtaining additional information about the analyte and reaction kinetics. A promising approach is proposed, which can be considered a simple and sensitive method for real-time detection of lactate dehydrogenase activity.