BACKGROUND Cancer treatment often fails due to multidrug resistance (MDR) of the tumor cells. One of the major causes is overexpression of P-glycoprotein (P-gp). MATERIALS AND METHODS By N-substitution reactions of diamine, amino acid and amino alcohol derivatives with 1-substituted tetrahydroisoquinoline skeleton, structurally diverse 1,2-disubstituted 1,2,3,4-tetrahydroisoquinolines were sy...

OBJECTIVES Hfq is a bacterial RNA chaperone involved in the post-transcriptional regulation of many stress-inducible genes via small non-coding RNAs. Although Hfq is related to important phenotypes including virulence in many bacterial pathogens, its role in drug resistance is unknown. The aim of this study was to investigate the role of Hfq in bacterial multidrug resistance. METHODS The hfq ...

We have studied the fluorescence emission by two-photon excitation of four dyes widely used for bioimaging studies, rhodamine 6G, fluorescein, pyrene and indo-1 at the single molecule level. The single dye molecules, spread on a glass substrate by spin coating, show a constant fluorescence output until a sudden transition to a dark state very close to the background. The bleaching time that is ...

The objective of our work has been the microencapsulation of dyes with lecithin from soybean, with the formation of liposomes, as a substitute for synthetic auxiliaries so as to improve the quality of the effluent. Current scenarios promote the disintegration and leakage of the liposomes, such as, changes in temperature, pH and the use of surfactants. Since dyeing process is a mix of all these ...

A new microsphere consisting of inorganic mesoporous silica nanoparticles (MSNs) and organic alginate (denoted as MSN@Alg) was successfully synthesized by air-dynamic atomization and applied to the intracellular drug delivery systems (DDS) of liver cancer cells with sustained release and specific targeting properties. MSN@Alg microspheres have the advantages of MSN and alginate, where MSN provi...

Gold nanorods can be internalized by macrophages (an important early cellular marker in atherosclerosis and cancer) and used as an imaging contrast agent for macrophage targeting. Objective of this study is to compare two-photon luminescence (TPL) properties of four aspect ratios of gold nanorods with surface plasmon resonance at 700, 756, 844 and 1060 nm respectively. TPL from single nanorods ...

The comparison of Förster resonance energy transfer (FRET) efficiencies between two fluorophores covalently attached to a single protein or DNA molecule is an elegant approach for deducing information about their structural and dynamical heterogeneity. For a more detailed structural interpretation of single-molecule FRET assays, information about the positions as well as the dynamics of the dye...