Probing the physicochemical interactions of 3-hydroxy-benzo[a]pyrene with different monoclonal and recombinant antibodies by use of fluorescence line-narrowing spectroscopy.

Characterization of interactions between antigens and antibodies is of utmost importance both for fundamental understanding of the binding and for development of advanced clinical diagnostics. Here, fluorescence line-narrowing (FLN) spectroscopy was used to study physicochemical interactions between 3-hydroxybenzo[a]pyrene (3OH-BaP, as antigen) and a variety of solvent matrices (as model systems) or anti-polycyclic aromatic hydrocarbon antibodies (anti-PAH). We focused the studies on the specific physicochemical interactions between 3OH-BaP and different, previously obtained, monoclonal and recombinant anti-PAH antibodies.

Oxazine dye-conjugated dna oligonucleotides: Förster resonance energy transfer in view of molecular dye-DNA interactions.

In this work, the photophysical properties of two oxazine dyes (ATTO 610 and ATTO 680) covalently attached via a C6-amino linker to the 5'-end of short single-stranded as well as double-stranded DNA (ssDNA and dsDNA, respectively) of different lengths were investigated. The two oxazine dyes were chosen because of the excellent spectral overlap, the high extinction coefficients, and the high fluorescence quantum yield of ATTO 610, making them an attractive Förster resonance energy transfer (FRET) pair for bioanalytical applications in the far-red spectral range. To identify possible molecular dye-DNA interactions that cause photophysical alterations, we performed a detailed spectroscopic study, including time-resolved fluorescence anisotropy and fluorescence correlation spectroscopy measurements.

Toward sensitive, quantitative point-of-care testing (POCT) of protein markers: miniaturization of a homogeneous time-resolved fluoroimmunoassay for prostate-specific antigen detection.

Point-of-care testing (POCT) systems which allow for a sensitive, quantitative detection of protein markers are extremely useful for the early detection and therapy progress monitoring of cancer. However, currently commercially available POCT devices are mainly limited to the qualitative detection of protein markers. In this study we demonstrate the successive miniaturization of a sensitive and fast assay for the quantitative detection of prostate-specific antigen (PSA) using a well established and clinically approved homogeneous time-resolved fluoroimmunoassay technology (TRACE®) on a commercial plate-reader system (KRYPTOR®).

Novel intramolecular energy transfer probe for the detection of benzo[a]pyrene metabolites in a homogeneous competitive fluorescence immunoassay.

The spectroscopic properties of a novel intramolecular energy transfer probe (ET probe)--consisting of 3-hydroxybenzo[a]pyrene (3OH-BaP) as the donor covalently linked to sulforhodamine B (SRB) as the acceptor--for the detection of polycyclic aromatic hydrocarbons (PAH) antibody binding were characterized. Absorption and fluorescence spectra as well as fluorescence decay curves were recorded in methanol and aqueous solution, respectively. For comparison, the parent chromophores 3OH-BaP and SRB were investigated as well.

Regulation of MDR1 gene expression in multidrug-resistant cancer cells is independent from YB-1.

The MDR1 gene encoded transmembrane ABC-transporter MDR1/P-glycoprotein can mediate the phenotype of multidrug resistance (MDR), a major obstacle in the clinical management of cancer patients. It was hypothesized that YB-1 is a fundamental regulatory factor of the MDR1 gene in tumor cells and can therewith enhance drug resistance. To analyze the potential impact of YB-1 in MDR cancer cells, two specific anti-YB-1 small interfering RNAs (siRNAs) were designed for transient triggering the gene-silencing RNA interference (RNAi) pathway in the MDR cell lines EPG85-257RDB and EPP85-181RDB as well as in their drug-sensitive counterparts EPG85-257P and EPP85-181P.