查看更多>>摘要：The structure-specific endonuclease FEN1 participates in various genome maintenance pathways in eukaryotes and is associated with different human diseases. Herein, we demonstrate label-free and homogeneous detection of FEN1 based on ligation-promoted hyperbranched rolling circle amplification (HRCA). This assay can be performed isothermally with the involvement of primers 1 and 2 and a circular DNA substrate with a 5'-flap. When FEN1 is present, it cleaves 5'-flap of circular DNA substrate to obtain a circular padlock probe with the assistance of Taq DNA ligase. The circular padlock probe can serve as a template to initiate HRCA in the presence of primers 1 and 2 and Vent (exo(-)) DNA polymerase. The obtained dsDNA fragments can produce an enhanced fluorescence signal with SYBR Green I as indicator. This method displays good specificity and high sensitivity, and it can be employed to screen FEN1 inhibitors and quantitatively detect FEN1 activity in human cancer cells, with potential applications in early diagnosis and drug discovery.
Majidi, Mir RezaFakhraei, MinaJahanban-Esfahlan, AliHejazi, Maryam...
24页
查看更多>>摘要：Up-to-date diagnostics is globally improved by point-of-care testing (POCT) analysis and bedside research works. Development in POCT analysis has been provided mostly by forward-looking engineering technology for biosensing and sensing assessments. Lately, lateral flow assays (LFAs) have attracted a lot of interest as a result of their noteworthy benefits including cost-effectiveness, better portability, being operator friendly and rapid detection. This technique has been employed broadly for monitoring diverse biomarkers linked to ultrasensitive detection of pathogenic bacteria, ecological monitoring, consumer protection, and infectious diseases. LFA analyses established on qualitative and optical outcomes have boosted the objectivity and data efficiency of the assessments. Therefore, developing novel methods with the capability of providing reliable and quantitative information regarding a target analyte in a model and preserving the qualities of LFAs is of great necessity. In this review, the main principles of LFAs, challenges, and prospects for more development in this field in sensing pathogenic bacteria have been summarized. Subsequently, visually-read LFAs improvement to further progressive platforms have been explored by considering the prospects of this very flexible method for ultrasensitive detection of pathogenic bacteria. In addition, novel labeling methodologies, electrochemical and optical transducers are described. Also, recent developments in these detection methods elements in combination with other considered approaches have been highlighted.
查看更多>>摘要：Oxidative stress plays significant roles in the development of various diseases. H2O2 acts as a signaling molecule physiologically or harmful substance pathologically and the mitochondria are one of the most active places for the generation of H2O2. Thus, a new mitochondria-targeted probe 1 for H2O2 detection was synthesized herein, based on D-pi-A structure with a large Stokes shift (150 nm) due to its ICT process. To improve its water solubility and sensitivity, probe 2 with PEG chain and probe 3 with two responsive boronated groups were then designed based on the structure of probe 1. As a result, the fluorescence intensity of probe 2 was far higher than that of probe 1 and probe 3 not only in vitro experiment but in cell imaging study with a larger linear range and signal-to-noise ratio, rendering it the best probe for further exogenous and endogenous H2O2 detection in Hela cells.
查看更多>>摘要：Guanine is the most susceptible to oxidation among all the DNA bases, and 8-oxo-7,8-dihydroguanine (OG) is one of main oxidation products that can occur in any part of chromosomal DNA. OG in the telomere sequence is associated with telomere shortening, cell aging, and dysfunction, and it may induce cancers. The accurate detection of OG in telomeres is important to early clinical diagnosis and molecular research. Herein, we develop a simple and rapid method to sensitively measure 8-oxo-7,8-dihydroguanine (OG) in telomeres of cancer cells by using Bsu polymerase-mediated fluorescence coding. This method is very simple without the requirement for any nucleic acid amplification or specific restriction enzyme recognition reaction, and Bsu polymerase can selectively incorporate Cy5-dATP into the opposite site of OG, endowing this method with good specificity. Moreover, the introduction of single-molecule detection significantly improves the sensitivity. This method can detect OG within 70 min with a limit of detection (LOD) of 2.45 x 10(-18) M, and it can detect OG in genomic DNA extracted from H2O2-treated HeLa cells with a LOD of 0.0094 ng, holding great potential in disease-specific gene damage research and early clinic diagnosis.
查看更多>>摘要：A novel fast and automatic methodology for the hierarchical classification and similarity matching of mid-infrared spectra of paint samples based on the principles of Soft Independent Modelling of Class Analogy (SIMCA) and on the definition and properties of the Mahalanobis distance is here proposed. This approach was tested in a so-called market study (i.e., targeting products largely accessible to the general public and conceived for a considerably wide range of usages) conducted across the surroundings of the city of Lille, in France, and has permitted not only to successfully achieve the chemical characterisation of most of the analysed samples but also to discover specific commonality patterns among specimens sharing the same chemical features.
查看更多>>摘要：Solid-state nanopore has the ability to detect proteins at a single-molecule level with its high sensitivity, high-throughput, and low cost. Improvements in fabrication, functionalization, and characterization of solid-state nanopores keep evolving. Various analytical methods targeted towards diagnostic applications using nanopore-based devices are appearing. This review article provides an overview of recent progress in the field of solid-state and biological nanopores for protein detection in a complex analyte. The advantages and challenges involved in nanopore sensing have been discussed. Further, the review surpasses the steady-state resistive pulse techniques of sensing and incorporate transient variations in the nanopore conductance. Application of the power spectral density of these fluctuations toward sensing has been highlighted with importance on reducing the detection limit in a complex environment. Lastly, the current problems and future perspectives have been discussed with a perspective to increase nanopores performance towards diagnostic applications in complex medium.
查看更多>>摘要：We developed a simple, inexpensive, environmentally friendly one-step fabrication of a flexible laser induced graphene-chitosan-gold nanoparticles (LIG-CS-AuNPs) electrode. The fabrication was based on a laser treatment of polyimide (PI) film coated with CS solution containing gold ions (Au (III)). The AuNPs decorating the induced 3D graphene composite were uniformly distributed. The electrode exhibited good electrical conductivity and excellent electrocatalytic activity toward the oxidation of UA. To enable on-site monitoring of uric acid (UA) in blood serum by differential pulse adsorptive stripping voltammetry (DPAdSV), the electrode was coupled to a portable potentiostat connected to a cellphone to control and monitor analysis. The affecting parameters of DPAdSV were optimized. Under the optimal conditions for UA determination, the limit of detection of the developed sensor was 0.33 mu mol L-1 and the limit of quantification 1.10 mu mol L-1. Two linear ranges were produced: 1.0-30 mu mol L-1 and 30-100 mu mol L-1. The sensor was highly sensitive and demonstrated excellent reproducibility and selectivity, determining UA in blood serum with recoveries between 86.6 +/- 0.6 and 94.7 +/- 0.4%. The analysis results were in agreement with those of the hospital standard enzymatic method.
查看更多>>摘要：In this work, a novel multifunctional nano-enzyme platform was developed and used for enzymatic and ratio metric electrochemical biosensing of uric acid (UA). Boron nanosheets (BNSs) were prepared through ultrasound assisted liquid-phase exfoliation, followed by the loading of doxorubicin (DOX) to form BNSs-DOX complex. The complex was drop-casted on glassy carbon electrode (GCE) surface to prepare BNSs-DOX/GCE. Cobalt-based metal-organic framework (MOF) with encapsulation of urate oxidase (UOx) was in-situ copolymerized and electrodeposited on the BNSs-DOX surface to construct UOx@MOF/BNSs-DOX nanohybrid-modified GCE. The modified electrode serves as an artificial nano-enzyme sensing platform and presents multifunctional functions, including DOX-loaded BNSs carrier, UOx-enzyme immobilization, enzymatic redox and ratiometric electrochemical sensing of UA. The platform was explored as a new ratiometric electrochemical biosensor to detect UA in the concentration range of 0.1-200 mu M, with a low limit of detection of 0.025 mu M. Experimental results testify high selectivity, sensitivity and stability toward efficient detection of UA over potential interferents, revealing high detection accuracy and repeatability. The explored biosensor shows superior detection performances in real biological samples, together with high detection recoveries. Excellent properties and functions endow the biosensor with great prospects for precise screening and early diagnosis of UA-relevant malignant diseases in clinic.
查看更多>>摘要：Globotriose (Gal-alpha 1, 4-Gal-beta 1, 4-Glc) is involved in binding with Shiga toxins (Stxs) produced by Shigella dys-enteriae and certain pathogenic Escherichia coli strains which could cause severe gastroenteritis and hemolytic uremic syndrome (HUS). Thus, this trisaccharide group and its derivatives provide potentials in the development of carbohydrate-based diagnostic and therapeutic reagents against bacterial infection. Instead of the tedious chemical synthesis of globotriose or its glycoconjugates, we reported a multi-step (step-wise) enzymatic synthesis system containing glucosyltransferase (ApNGT, E.C. 4.3.3.5), beta-1, 4-galactosyltransferase (LgtB, E.C. 2.4.1.22) and alpha-1, 4-galactosyltransferase (LgtC, E.C. 2.4.1.44) to produce globotriose-containing glycopeptides. In addi-tion, based on the specific binding between Stxs and globotriose, a cost-efficient, convenient, ultra-sensitive and specific colorimetric biosensor was further constructed to detect Stxs using glycoconjugated Au@Fe-TFPA-COP (globotriose@Au@Fe-TFPA-COP) as a nanoenzyme catalyst. We estimate that this method conveniently applied in the detection of Stx-producing bacteria and associated infectious diseases.
查看更多>>摘要：Pillar [5]arene, a new water-soluble carboxylatopillar [5]arene ammonium salts (WP5), has been employed as the host for complexation of guest molecules. Herein, a visible light driven WP5 functionalized gold nanoparticles (Au@WP5) was fabricated for ultrasensitive photelectrochemical (PEC) detection of caffeic acid (CA). The ultraviolet-visible spectrum characteristics, PEC response results of samples in caffeic acid solution confirm the localized surface plasmon resonance effect of Au NPs and the host-guest interaction between WP5 and CA are responsible for the enhanced PEC sensing performance. Under optimal conditions, the sensitive PEC sensor constructed with Au@WP5 exhibited the concentration linear range from 0.025 mu M to 370 mu M and a detection limit of 0.01 mu M (S/N = 3). Importantly, the good anti-interference ability, stability and reproducibility of the proposed PEC sensor providing the promising detection application of pillar [5]arene functionalized photoactive materials in food and drinks.
NSTL
Elsevier