Introduction Fluorescence spectrophotometry in its pure form is inherently a very sensitive analytical method. Single molecules have been observed in fluorescence microscopy due to the very low signal in the absence of fluorescent analytes (often referred to as zero background) and the possibility of producing many photons from a single molecule using a very bright excitation source. There are ...

Kinesin-1 motor proteins move along microtubules in repetitive steps of 8 nm at the expense of ATP. To determine nucleotide dwell times during these processive runs, we used a Förster resonance energy transfer method at the single-molecule level that detects nucleotide binding to kinesin motor heads. We show that the fluorescent ATP analog used produces processive motility with kinetic paramete...

Method for robust demarcation of the basal cell carcinoma (BCC) is presented employing novel dependent component analysis (DCA)-based approach to unsupervised segmentation of the red-green-blue (RGB) fluorescent image of the BCC. It exploits spectral diversity between the BCC and the surrounding tissue. DCA represents an extension of the independent component analysis (ICA) and is necessary to ...

Microscopic fluorescent samples of interest to cell and molecular biology are commonly embedded in an aqueous medium near a solid surface that is coated with a thin film such as a lipid multilayer, collagen, acrylamide, or a cell wall. Both excitation and emission of fluorescent single molecules near film-coated surfaces are strongly affected by the proximity of the coated surface, the film thi...

In this article, we established a fluorescent chiral recognition and detection method for cysteine based on the L-glutathione (L-GSH)-stabilized Ag nanoclusters (AgNCs) with high selectivity and sensitivity. A fast and green microwave (MW)-assisted strategy has been employed for synthesizing water-soluble fluorescent L-GSH-AgNCs. The reaction time was shortened from hours to several minutes. Th...

Standard deviation measurements of intensity profiles of stationary single fluorescent molecules are useful for studying axial localization, molecular orientation, and a fluorescence imaging system's spatial resolution. Here we report on the analysis of the precision of standard deviation measurements of intensity profiles of single fluorescent molecules imaged using an EMCCD camera.We have dev...

Fluorescent biosensors have been widely used in biomedical applications. To amplify the intensity of fluorescence signals, this study developed a novel structure for an evanescent wave fiber-optic biosensor by using a Fabry-Perot resonator structure. An excitation light was coupled into the optical fiber through a laser-drilled hole on the proximal end of the resonator. After entering the reson...

A band that is strongly fluorescent and migrates electrophoretically with serum albumin is commonly found in electrophoretograms of sera from patients with chronic renal failure. We sought to determine whether the fluorescence originates from binding of certain still-unidentified metabolites or drugs, from an abnormal albumin species, or from some other protein entity. Molecular-exclusion colum...

We report a novel technique for generating polymer fluorescent barcode nanorods by reactive ion etching of polymer multilayer films using nonclose-packed (ncp) colloidal microsphere arrays as masks. The fluorescent polymer multilayer films were spin-coated on a substrate, and ncp microsphere arrays were transferred onto these films. The exposed polymers were then etched away selectively, leavin...

Three fluorescent probes TP1–3 for thiols were rationally designed and synthesized to distinguish cysteine (Cys) from glutathione (GSH)/homocysteine (Hcy). TP1–3 are almost non-fluorescent and colorless 4-nitro-1,8-naphthalimide derivatives. Upon the substitution of nitro by Cys, TP1–3 were transformed into weakly fluorescent green-emitting 4-amino analogs via highly fluorescent blue-emitting t...