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Detection of specific biomarkers in cell membranes is critical for cell biology and disease theranostics. Here we develop a versatile terminal protection assay strategy for wash-free quantification and imaging of cell surface proteins using small molecule-linked DNA with programmable signal sequences. DNA probes are designed to link to a small molecule ligand at 3′ end for specific recognition of...
A label-free nanopore biosensor for detection of DNA target is proposed utilizing hybridization chain reaction (HCR) strategy for signal amplification. The DNA target triggered HCR to form large DNA nanostructure inside the nanopore and out the nanopore membrane, which inducing the ionic current decrease effectively due to the blockage of the nanopore. The developed method achieves a desirable sensitivity...
Ordered mesoporous silica (OMS) film supported on anodized titanium wire was fabricated as a new solid phase microextraction (SPME) fiber for the extraction of chlorophenols (CPs) from aqueous media followed by the determination with gas chromatography flame ionization detection (GC-FID). The supported OMS film was prepared via a solvent evaporation-induced self-assembly approach (EISA) combined with...
A novel mitochondria-targeted ratiometric near-infrared fluorescence probe NDMBT for Sulfur dioxide (SO2) derivatives was constructed based on the SO2 derivatives-triggered Michael addition reaction. It displayed ultrafast response time (within 10s), large hypsochromic shift (260nm), high photostability, excellent selectivity and high sensitivity in aqueous media with a detection limit of 43nM. More...
A turn-on fluorescent probe (Naphsulf-O) for hydrazine was developed by protecting the hydroxy group of the fluorophore 6-acetyl-2-hydroxynaphthalene via O-4-nitrobenzenesulfonylation, where 4-nitrobenzene was used as a fluorescence quenching moiety as well as an electrophile. Upon nucleophilic aromatic substitution (NAS) reaction of hydrazine toward the probe, the protecting group was removed and...
Most of the proteins locate more than one organelle in a cell. Unmixing the localization patterns of proteins is critical for understanding the protein functions and other vital cellular processes. Herein, non-linear machine learning technique is proposed for the first time upon protein pattern unmixing. Variable-weighted support vector machine (VW-SVM) is a demonstrated robust modeling technique...
The study of spatial distribution characteristics of the adsorbed compounds for absorbent materials has significant importance in understanding the behaviors of aerosols while they migrating in the absorbent materials. Herein, for the first time, desorption corona beam ionization–mass spectrometry (DCBI–MS) has proposed for direct in-situ analysis of adsorbed aerosol for absorbent materials. DCBI...
A fluorescent probe was synthesized and demonstrated to be highly selective and sensitive in the reaction with copper (II) ion, generating a large variation of the fluorescence intensity in a dose–response manner. The probe contains a dansyl moiety as fluorophore and a multidentate ligand for copper (II) ion recognition. The reaction of the molecular probe with copper (II) ion proceeds rapidly and...
A turn-on fluorescence probe for zinc ion has been synthesized, which contains a symmetric pseudo salen moiety as zinc recognition site. The multidentate salen ligand chelates with zinc ions, and generates the rigidity of the zinc complex, which subsequently results in a dramatic fluorescence enhancement of the probe. Mass spectral and spectroscopic results reveal that the reaction proceeds rapidly...
DNA sequences with guanine repeats can be induced to form G-quartets that adopt G-quadruplex structures in the presence of thioflavin T (ThT). ThT plays a dual role of inducing DNA sequences to fold into quadruplex structures and of sensing the change by its remarkable fluorescence enhancement. ThT binding to the DNA sequences with guanine repeats showed highly specific fluorescence enhancement compared...
Rapid, sensitive and quantitative assays for peptide hydrolysis enzymes are of paramount importance for drug development and in the diagnosis of disease. Here, we proposed a novel biosensor for sensitive and selective active screening of peptidases. This strategy relies on the proteolysis-mediated protection of gold nanoparticles (AuNPs) that were decorated with biotin-labeled substrate peptides and...
Activity screening of DNA base excision repair (BER) enzymes is a crucial step for understanding numerous fundamental biochemical processes. A novel label-free homogeneous technique is developed for visualized uracil-DNA glycosylase (UDG) activity assay using gold nanoparticles (AuNPs). This strategy relies on the enzyme-catalyzed assembly of AuNPs decorated with DNA probes. In the presence of endonuclease...
As a greedy search algorithm, classification and regression tree (CART) is easily relapsing into overfitting while modeling microarray gene expression data. A straightforward solution is to filter irrelevant genes via identifying significant ones. Considering some significant genes with multi-modal expression patterns exhibiting systematic difference in within-class samples are difficult to be identified...
Representing a compound by a numerous structural descriptors becomes common in quantitative structure–activity relationship (QSAR) studies. As every descriptor carries molecular structure information more or less, it seems more advisable to investigate all the possible descriptor vectors rather than traditional variable selection when building a QSAR model. Based on particle swarm optimization (PSO)...
One problem with discriminant analysis of microarray data is representation of each sample by a large number of genes that are possibly irrelevant, insignificant or redundant. Methods of variable selection are, therefore, of great significance in microarray data analysis. To circumvent the problem, a new gene mining approach is proposed based on the similarity between probability density functions...
An unlooked-for experimental observation that in near-infrared spectroscopy (NIR) the absorption peak of the second overtone of aniline adsorbed by 13X molecular sieve nearly disappeared led us investigate a fundamental question: the behavior of NIR when the outside space surrounding a molecule is too small to allow the molecule to vibrate freely. Through NIR of various organic compounds adsorbed...
In this study, we have proposed a novel strategy for the rapid identification and high sensitive detection of different kinds of cancer cells by means of electrochemical and contact angle measurements. A simple, unlabeled method based on the functionalized Au nanoparticles (GNPs) modified interface has been utilized to distinguish the different cancer cells, including lung cancer cells, liver cancer...
A highly sensitive chemiluminescence immunosensor for the detection of prostate-specific antigen (PSA) was developed based on a novel amplification procedure with the application of enzyme encapsulated liposome. Horseradish peroxidase (HRP) encapsulated and antibody-modified liposome acts as the carrier of a large number of markers and specific recognition label for the amplified detection of PSA...
A novel, sensitive electrochemical immunoassay in a homogeneously dispersed medium is described herein based on the unique features of agarose beads and the special amplified properties of biometallization. The immunochemical recognition event between human immunoglobulin G (IgG) and goat anti-human IgG antibody is chosen as the model system to demonstrate the proposed immunoassay approach. Avidin-agarose...
A sensitive immunosensor using colloidal gold as electrochemical label is described. In this method, the capture protein was first immobilized on a carbon paste electrode surface through passive adsorption to bind quantitatively with corresponding antigen and colloidal gold labeled antibody to perform a sandwich assay. To detect the amount of the colloidal gold captured on the electrode surface, the...
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