Sensors & diagnostics最新文献

Electrogenerated chemiluminescence, also called electrochemiluminescence (ECL), has attracted much attention in various fields of analysis due to its high sensitivity, extremely wide and dynamic range and excellent control of space and time of the light emission. The great success of ECL for in vitro detection results from the advantages of combining the selectivity of biological recognition elements and the sensitivity and controllability of ECL technology. ECL is widely applied as a powerful analytical technique for ultrasensitive detection of biomolecules. In this review, we summarize the recent developments and applications of ECL for immunosensing. Herein, we present the sensing schemes and their applications in different areas, such as detection of biomarkers, bead-based detection and bacteria and cell analysis and provide future perspectives on new developments in ECL immunosensing. In particular, ECL-based sensing assays for clinical sample analysis and medical diagnostics and the development of immunosensors for these purposes are highlighted.

The biological taste sensing system has a sensitive perception ability for taste substances (tastants) and is considered as one of the most efficient chemical sensing systems in nature. With the rapid development of human society, biomimetic taste-based biosensors have become increasingly important to improve human life quality and ensure human health, and have been widely applied in many fields such as food safety, biomedicine, and public health. In recent years, researchers have been devoted to developing a new type of chemical sensing system. Among them, biomimetic olfactory-based biosensors have shown promising prospects and potential applications compared to traditional chemical sensors due to the utilization of well-developed natural molecular recognition mechanisms. Biomimetic taste-based biosensors usually employ biologically originated taste cells, taste receptors, taste buds, taste organoids and lipid membranes as sensitive elements, combined with secondary transducers to achieve specific and sensitive detection of tastants in order to obtain comparable detection performance to that of the biological taste system. This review summarizes the most recent advances in biomimetic taste-based biosensors based on biological taste sensing elements. First, the basic principle of biomimetic taste-based biosensors is briefly introduced. Then, the system composition and development of biomimetic taste-based biosensors are outlined and discussed in detail, with a focus on the preparation technology of sensitive elements and their coupling with transducers. In addition, the performance of biomimetic taste-based biosensors and their applications in food quality testing and basic and clinical research are summarized. Finally, the current challenges and development trends of biomimetic taste-based biosensors are proposed and discussed.

Rapid and efficient early-stage tumor detection is crucial in cancer diagnostics. Recent research indicates that microRNA-141 expression levels serve as a predictive biomarker for prostate cancer cell count in the human body. In this study, we developed an original competitive system for miRNA-141 detection using Prussian blue nanoparticles (PBNPs), comparing it with a horseradish peroxidase (HRP)-based competitive system for the same target. The competitive system involved miRNA-141 and biotin-miRNA-141 on a magnetic bead-modified capture probe specific to miRNA-141. The synthesized PBNPs were conjugated to avidin, resulting in the formation of avidin–PBNPs. These conjugates were used as a substitute for streptavidin–HRP. The peroxidase-like activity of PBNPs catalyzed the colorimetric substrate (3,3′,5,5′-tetramethylbenzidine), producing a distinct blue color measured at 630 nm. Under optimal conditions, both PBNPs and HRP-based systems exhibited a linear response to miRNA-141 concentrations (50 pM to 300 pM and 80 pM to 500 pM, respectively). Among the two systems investigated in this study, the PBNPs-based bio-assay demonstrated exceptional sensitivity, achieving a remarkably low LOD of 0.61 pM and an analysis time of 32 minutes. These biosensors successfully determined miRNA-141 levels in spiked human serum.

Visual analysis methods have received widespread attention due to their simplicity, economy, and intuitive results. In this work, a visual DNA quantitative analysis method based on surface selective site-directed crystallization (SSSC) was developed. Firstly, we explored the formation of calcium carbonate crystals with unique polymorphism induced by the surface of functionalized glass slides with different groups; among them, the calcite induced by the –COOH functional group has a uniform shape, larger size, and even distribution, so it serves as a signal promoter. In contrast, due to the –N(CH₃)₃ group acting as a signal inhibitory molecule by inhibiting crystallization, the signal molecule is captured through DNA hybridization, and the crystallization reaction is performed. The calcite growing on the DNA site is visible to the naked eye, and the DNA molecules hybridized on the surface of the glass slide are further quantified. The detection limit of this proposed visual method is 0.1 fM, and only a smartphone is needed to complete basic quantification. This work provides a basis for research into the use of single crystals as digital readouts in the field of DNA analysis, with the advantages of being simple and economical and requiring minimal equipment.

Site-specific protein : DNA conjugation is gaining increasing importance in detection technologies such as quantitative immuno-PCR (qIPCR). Until now, DNA-binding proteins have been a relatively untapped source of protein : DNA conjugation systems. In Escherichia coli, the biotin protein ligase (BirA) is a biotin-dependent DNA-binding protein that offers a means to connect a protein of interest (POI) with DNA. Here, we explored BirA as a unique on–off protein : DNA connection switch for the production of self-assembling POI : DNA conjugates. Green fluorescent protein (GFP) is a versatile protein tag and reporter, commonly quantified by fluorescence detection. However, low GFP concentrations are challenging to detect and require more sensitive methods. A multitude of high-affinity antibodies are available for capture and detection of GFP as an affinity tag. As such, a well-characterised GFP-tagged BirA (BirA-GFP) was selected for the development and validation of an innovative qIPCR platform technology. The unique principle of this assay involves the assembly of two BirA-GFP with the bioO repressor DNA sequence in the presence of ATP and biotin. The resulting high affinity bioO : BirA-GFP complex can be applied in various formats to detect the presence of anti-GFP IgG as well as GFP immobilised on a surface. Complete release of the quantifiable bioO DNA can easily be achieved by omitting ATP and biotin in the final elution step. The new BirA-based qIPCR assay enabled picomolar (≥10⁻¹² M) detection of GFP and anti-GFP IgG as well as their affinity profiling.

A hybrid electrochemical DNA biosensor that integrates various technologies, such as laminar flow, surface hybridization, DNA-microarray, thermo-responsive nanocoating and localized photothermal heating, is presented here. A photothermal module based on gold nanostructures photoactivated by a green-light source (532 nm) was developed for easy temperature management. The hybridization product is electrochemically detected by a three-planar-microelectrode system upon dsDNA denaturation. Performances of the hybrid biosensor were investigated by detection of the cDNA target, resulting in a sensitivity of about 2.62 μA nM⁻¹ cm⁻² and a limit of detection of 1.5 nM, as a function of the capture probe sequence. The findings facilitate the integration of multiple technologies, enabling the development of low-cost and point-of-care detection systems for molecular analysis.

Reckoning the significance of next-generation biosensors and point-of-care sensors, scientists are interested in developing superior nanomaterials with advantageous characteristics that can serve as electrode modifiers in the development of functional devices. MXenes are a broad class of two-dimensional metal carbides and nitrides characterized by their exceptional hydrophilicity, high specific surface area, and high conductivity. MXenes and their derived nanocomposites are presently gaining importance as electrode materials for the electrochemical detection of various biomarkers. This review assesses and summarises current notable accomplishments in the concepts, fabrication, and diverse applications of MXene-based nanocomposites for electrochemical monitoring of a variety of clinically relevant biomarkers. Furthermore, an outline of the existing impediments linked to technological advancement is included, accompanied by proposals for further investigation into the issues.

Given the susceptibility of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) and Norovirus (NoV) to survive in cold chain food, thereby posing significant public health risks, we present a novel approach for biosensor development utilizing a graphene field-effect transistor (GFET) modified with nucleic acid aptamers. The biosensor's innovative design incorporates 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE) as a coupling agent to facilitate the attachment of nucleic acid aptamers onto channel graphene. This modification induces a redistribution of charge on the graphene surface, resulting in a shift of the Dirac point upon target capture by the nucleic acid aptamer. Through this pioneering methodology, we successfully engineered SARS-CoV-2 GFET and NoV GFET biosensors capable of detecting trace amounts of SARS-CoV-2 and norovirus within a rapid 5-minute timeframe, showcasing detection limits of 33 fg mL⁻¹ and 6.17 pg mL⁻¹, respectively. Subsequently, we applied these sensors to detect SARS-CoV-2 in frozen meat and norovirus in shellfish, yielding promising results with excellent specificity and stability. This groundbreaking sensing mechanism holds significant promise for the detection of foodborne viruses across a diverse range of food samples.

Electrochemical aptamer-based (EAB) sensors represent a promising biosensing platform, leveraging the selectivity of aptamers and the advantages of electrochemical methods. These sensors offer high sensitivity, rapid response, low limits of detection, cost-effectiveness, and miniaturization potential. While gold electrodes have been predominantly used in EAB sensors, alternatives such as carbon nanotubes (CNTs) are gaining attention. CNTs offer advantages like large surface area and conductivity but pose challenges due to their reactivity and 3D network structure. In this study, we explore the development of EAB sensors using single-wall carbon nanotube (SWCNT) networks, emphasizing on the challenges and electroanalytical insights. Three key electrochemical parameters are proposed for assessing EAB sensor performance: (i) variations in peak current, (ii) shifts in peak position, and (iii) the restoration of the background current. Focusing solely on peak current changes can be misleading, as factors like aptamer surface depletion can influence it. Additionally, both partial and integrated currents should be monitored in square wave voltammetry (SWV) analysis, considering both ON and OFF behaviours across frequencies. This comprehensive approach provides a preliminary assessment of successful binding and surface passivation in EAB sensors when combined with surface analytical techniques such as surface plasmon resonance (SPR) measurements.

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