Solvent-Induced Swelling Behaviors of Microphase-Separated Polystyrene--Poly(ethylene oxide) Thin Films Investigated Using In Situ Spectroscopic Ellipsometry and Single-Molecule Fluorescence Microscopy.

Block copolymers have attracted considerable interest in the fields of nanoscience and nanotechnology because these polymers afford well-defined nanostructures via self-assembly. An in-depth understanding of solvent effects on the physicochemical properties of these microdomains is crucial for their preparation and utilization. Herein, we employed in situ spectroscopic ellipsometry and single-molecule fluorescence techniques to gain detailed insights into microdomain properties in polystyrene--poly(ethylene oxide) (PS--PEO) films exposed to ethanol- and water-saturated N.

Investigation of Molecular Diffusion at Block Copolymer Thin Films Using Maximum Entropy Method-Based Fluorescence Correlation Spectroscopy and Single Molecule Tracking.

Fluorescence correlation spectroscopy (FCS) has been widely used to investigate molecular diffusion behavior in various samples. The use of the maximum entropy method (MEM) for FCS data analysis provides a unique means to determine multiple distinct diffusion coefficients without a priori assumption of their number. Comparison of the MEM-based FCS method (MEM-FCS) with another method will reveal its utility and advantage as an analytical tool to investigate diffusion dynamics.

Influences of Hydrogen Bonding-Based Stabilization of Bolaamphiphile Layers on Molecular Diffusion within Organic Nanotubes Having Inner Carboxyl Groups.

This paper reports molecular diffusion behavior in two bolaamphiphile-based organic nanotubes having inner carboxyl groups with different inner dimeters (10 and 20 nm) and wall structures, COOH-ONT and COOH-ONT, using imaging fluorescence correlation spectroscopy (imaging FCS). The results were compared to those previously obtained in a similar nanotube with inner amine groups (NH-ONT). COOH-ONT, as with NH-ONT, were formed from a rolled bolaamphiphile layer incorporating triglycine moieties, whereas COOH-ONT consisted of four stacks of triglycine-free bolaamphiphile layers.

Diffusion Behavior of Differently Charged Molecules in Self-Assembled Organic Nanotubes Studied Using Imaging Fluorescence Correlation Spectroscopy.

The diffusion behavior of fluorescent molecules within bolaamphiphile-based organic nanotubes (ONTs) was systematically investigated using imaging fluorescence correlation spectroscopy (imaging FCS). Anionic sulforhodamine B, zwitterionic/cationic rhodamine B, or cationic rhodamine 123 was loaded into ONTs having cylindrical hollow structures (ca. 10 nm in inner diameter) with amine and glucose groups on the inner and outer surfaces, respectively.

Spectroscopic imaging studies of nanoscale polarity and mass transport phenomena in self-assembled organic nanotubes.

Synthetic organic nanotubes self-assembled from bolaamphiphile surfactants are now being explored for use as drug delivery vehicles. In this work, several factors important to their implementation in drug delivery are explored. All experiments are performed with the nanotubes immersed in ethanol.

Imaging fluorescence correlation spectroscopy studies of dye diffusion in self-assembled organic nanotubes.

The rate and mechanism of diffusion by anionic sulforhodamine B (SRB) dye molecules within organic nanotubes self-assembled from bolaamphiphile surfactants were investigated by imaging fluorescence correlation spectroscopy (imaging-FCS). The inner and outer surfaces of the nanotubes are terminated with amine and glucose groups, respectively; the former allow for pH-dependent manipulation of nanotube surface charge while the latter enhance their biocompatibility. Wide-field fluorescence video microscopy was used to locate and image dye-doped nanotubes dispersed on a glass surface.

Elongation, alignment, and guided electrophoretic migration of ds-DNA in flow-aligned hexagonal F127 gels.

Elongation, alignment, and electrophoretic migration of double stranded DNA (ds-DNA) are investigated within flow aligned hexagonal Pluronic F127 mesophases contained in microfluidic channels. The DNA molecules are stained with YOYO-1 for visualization of their positions, conformations, and motions, which are recorded by wide-field fluorescence video microscopy. The videos show that the ds-DNA molecules are elongated in flow aligned hexagonal F127 mesophases, with the long axis of the DNA molecules aligned parallel to the flow direction.