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Circulating tumor DNA (ctDNA) identification is one of the most meaningful approaches towards early cancer diagnosis. However, effective and practical methods for analyzing this emerging class of biomarkers are still lacking. In this work, a biosensor based on nitrophenyl functionalized black phosphorus nanosheets (NP-BPs) is fabricated for sensitive and selective detection of ctDNA. In this work, a nitrophenyl functionalized black phosphorus nanosheets (NP-BPs) biosensor is fabricated for sensitive and selective detection of ctDNA. Due to the successful nitrophenyl functionalization, the NP-BPs biosensor shows higher quenching efficiency and stronger affinity towards single-stranded DNA (ssDNA), as compared with double-stranded DNA (dsDNA). Therefore, the NP-BPs biosensor exhibits 5.4-fold fluorescence enhancement when dye-labelled ssDNA probe forms dsDNA in the presence of its specific ctDNA target. This biosensor exhibits a detection limit of 50 fM and a wide linear detection range of 50 fM-80 pM, provides reliable readout in a short time (15 min). Moreover, the NP-BPs-based biosensor could be applied to discriminate single nucleotide polymorphisms in clinical serum samples. It is envisioned that the NP-BPs-based sensing platform has great potentials in early cancer diagnosis and monitoring cancer progression.RNA detection permits early diagnosis of several infectious diseases and cancers, which prevent propagation of diseases and improve treatment efficacy. However, standard technique for RNA detection such as reverse transcription-quantitative polymerase chain reaction has complicated procedure and requires well-trained personnel and specialized lab equipment. These shortcomings limit the application for point-of-care analysis which is critical for rapid and effective disease management. The multicomponent nucleic acid enzymes (MNAzymes) are one of the promising biosensors for simple, isothermal and enzyme-free RNA detection. Herein, we demonstrate simple yet effective strategies that significantly enhance analytical performance of MNAzymes. The addition of the cationic copolymer and structural modification of MNAzyme significantly enhanced selectivity and activity of MNAzymes by 250 fold and 2,700 fold, respectively. [https://www.selleckchem.com/products/Cytarabine(Cytosar-U).html DNA Repair inhibitor] The highly simplified RNA detection system achieved a detection limit of 73 fM target concentration without additional amplification. The robustness of MNAzyme in the presence of non-target RNA was also improved. Our finding opens up a route toward the development of an alternative rapid, sensitive, isothermal, and protein-free RNA diagnostic tool, which expected to be of great clinical significance.The increasing level of pesticides and herbicides in food and water sources is a growing threat to human health and the environment. The development of portable, sensitive, specific, simple, and cost-effective sensors is hence in high demand to avoid exposure or consumption of these chemicals through efficient monitoring of their levels in food as well as water samples. The use of nanomaterials (NMs) for the construction of an immunosensing system was demonstrated to be an efficient and effective option to realize selective sensing against pesticides/herbicides. The potential of such applications has hence been demonstrated for a variety of NMs including graphene, carbon nanotubes (CNTs), metal nanoparticles, and nano-polymers either in pristine or composite forms based on diverse sensing principles (e.g., electrochemical, optical, and quartz crystal microbalance (QCM)). This article evaluates the development, applicability, and performances of NM-based immunosensors for the measurement of pesticides and herbicides in water, food, and soil samples. The performance of all the surveyed sensors has been evaluated on the basis of key parameters, e.g., detection limit (DL), sensing range, and response time.Primary cell wall (PCW) is a rigid yet flexible cell wall surrounding plant cells and it plays key roles in plant growth, cell differentiation, intercellular communication, water movement and defence. As a technique widely used to study the characteristics of mammalian cells, electrical impedance spectroscopy (EIS) is rarely used in plant science. In this work, we designed and fabricated an EIS based biosensor coupled with microfluidic platform to investigate the formation process of PCWat the single-cell level. Arabidopsis mesophyll cells with completely regenerated PCW showed significantly higher impedance values compared to the nascent protoplasts without PCW, demonstrating that PCW formation caused a dramatic change in cell electrical properties. The device could also discriminate plant mutant cells with modified PCW compositions, thus provided a novel tool for physical phenotyping of plant cells. The dose-dependent effects of exogenously applied auxin on PCW regeneration were corroborated on this platform which revealed its potential to sensitively detect the influences of in vitro stimuli. This work not only provided one novel application of impedance-based biosensor to characterize a plant-specific developmental event, but also revealed the promises of EIS integrated microfluidic system as a sensitive, time-effective and low-cost platform to characterize single plant cells and make new scientific discoveries in plant science.Herein, size-controllable molybdenum carbide nanoparticles (Mo2C NPs) encapsulated by N, P-codoped carbon shells which simultaneously wrapping on the surface of carbon nanotube (Mo2C@NPC/CNT) is synthesized through a molecular-scale cage-confinement pyrolysis route. Such confinement achieves a good coating and protection of Mo2C and the effective control over the size of Mo2C NPs ranging from 2.5 to 10 nm facilitates a rational investigation into their electrochemical sensor behavior at nanometer scales. The optimized structure consisting of Mo2C nanoparticles with size of ~5 nm showed an outstanding electrochemical response toward dopamine (DA) and acetaminophen (AC) with detection limits (S/N = 3) of 0.008 μM for AC and 0.01 μM for DA.Electrochemiluminescence (ECL) is a powerful (bio)analytical method based on an optical readout. It is successfully applied in the heterogeneous format for immunoassays and imaging using the model and most widely used ECL system, which consists of the immobilized [Ru(bpy)3]2+ label with tripropylamine (TPA) as a coreactant. However, a major drawback is the significant decrease of the ECL intensity over time. Herein, to decipher the process responsible for this progressive loss of ECL signal, we investigated its electrochemical and photophysical properties by mapping the luminescence reactivity at the level of single micrometric beads. Polystyrene beads were functionalized by the [Ru(bpy)3]2+ dye via a sandwich immunoassay or a peptide bond. ECL emission was generated in presence of the very efficient TPA coreactant. Imaging both photoluminescence and ECL reactivities of different regions (located near or far from the electrode surface) of a [Ru(bpy)3]2+-decorated bead allows us to demonstrate the remarkable photophysical stability of the ECL label, even in presence of the very reactive electrogenerated TPA radicals.