Syntheses and properties of photostable near-infrared cyanines and their cyclodextrin conjugates

Three fluorescent indocyanines containing p-carboxybenzyl groups on N atoms in the heterocyclic tings were synthesized under supersonic. The maxima wavelength of the absorption and emission of the dyes were 550-800 nm in water. Compared with those in aqueous solutions, the fluorescence intensity of the dyes in the α/β-cyclodextrin, Al^3＋, Zn^2＋, Sn^2＋ or the α/β-cyclodextrin in the aqueous solutions of the cations became stronger. The crystal Shapes of the dyes and their cyclodextrin inclusions were mostly acicular or polygon. The NHS-carboxyl squarylium indocyanine was prepared and used to conjugate with taurine or benzylamine, the results indicated that the dyes could couple covalently to biomass containing free NH2 group. Structure and some thermal parameters of the molecule of the trimethine cyanine were obtained by DFT method of Gaussian O3.     

Electrochemical Biosensing for Cancer Cells Based on TiO2/CNT Nanocomposites Modified Electrodes

Both TiO₂ nanoparticles and carbon nanotubes have been usually utilized to modify the electrodes to enhance the detection sensitivity of biomolecular recognition. In this research, novel TiO₂/CNT nanocomposites have been prepared and doped on the carbon paper as the modified electrodes. Subsequently, the redox behavior of the ferricyanide probe and the surface properties of the cancer cells coated on the modified electrodes have been investigated by using electrochemical and contact angle measurements. Compared with electrochemical signals on bare carbon paper and nanocomposite modified substrates, the significantly enhanced electrochemical signals on the modified electrodes covered with cancer cells have been observed. Meanwhile, different leukemia cells (i.e., K562/ADM cells and K562/B.W. cells) could be also recognized because of their different electrochemical behavior and hydrophilic/hydrophobic features on the modified electrodes due to the specific components on the plasma membranes of the target cells. This new strategy may have potential application in the development of the biocompatible and multi‐signal responsive biosensors for the early diagnosis of cancers.     

Review: Recent Developments in Enzyme-Based Biosensors for Biomedical Analysis

The need for simple, rapid, cost-effective, and portable screening methods has boosted the development of practical biosensors with applications in clinical monitoring, and diagnosis of disease. Compared with traditional analytical methods, enzyme-based bioanalytical devices have several distinct advantages such as high sensitivity and specificity, portability, cost-effectiveness, and the possibilities for miniaturization and mass production. Additionally, they can be developed for point-of-care diagnostic testing. This paper reviews recent advances in the development of enzyme biosensors, design characteristics, performances, and applications with a focus on electrochemical and optical sensors. Recent emerging technologies and innovative biosensing designs, such as nanosensors, paper based-sensors, lab-on-a-chip, biochips, and microfluidic devices are discussed. Specific applications in bioanalysis, clinical diagnosis, and pharmacology are discussed.     

High-throughput bioanalysis with simultaneous acquisition of metabolic route data using ultra performance liquid chromatography coupled with time-of-flight mass spectrometry

The capability of ultra performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/TOFMS) in the high-throughput quantitative analysis of a drug candidate in plasma has been investigated. Data obtained were compared with results from conventional analysis by high-performance liquid chromatography with tandem mass spectrometric detection on a triple quadrupole instrument (HPLC/MS/MS). The accuracies and precisions of the two approaches were comparable. The UPLC/TOFMS system displayed excellent robustness over the course of 276 injections of protein-precipitated plasma samples. With the instrumentation used, the limits of detection and quantification were approximately five-fold higher with UPLC/TOFMS than for HPLC/MS/MS. Nevertheless, the UPLC/TOFMS system proved adequate to quantify plasma concentrations of a drug molecule administered orally to rats at a pharmacologically relevant dose of 4 mg/kg. As well as providing quantitative data on the test compound, it was also possible to extract data for eight different metabolites, including several isomeric species (three +O and three +2O) from the UPLC/TOFMS data sets, using an analytical method with a 2.5-minute run time. Selectivity for the test compound and its metabolites was derived from the accurate mass capabilities of the TOF instrument, and no MS method development was required.