Eun Chul Cho

This Letter presents a new method for differentiating the Au nanospheres attached to the cell surface from those being internalized into the cells. We introduced an etching solution based on I2 and KI that can selectively dissolve the Au nanospheres on the cell surface within a short period of time. The advantage of this etchant is its low toxicity to the cells because it is capable of etching away a relatively large amount of Au nanospheres at a low molar concentration. By combining with quanti

The size, shape, and surface chemistry of a gold nanostructure can influence its adsorption and internalization by a cell (see image). This work compares gold nanostructures of two different sizes, two different shapes, and three different surface functional groups. Gold-based nanostructures have received increasing interest in biomedical applications owing to their unique optical and photothermal properties.1 These properties arise from a phenomenon known as localized surface plasmon resonance

It has been suggested that the phase transition of the poly( N -isopropylacrylamide) (PNiPAM) aqueous solution consists of at least two different processes: (1) a rearrangement of bound water around either hydrophobic or hydrophobic and hydrophilic group of PNiPAM and (2) a hydrophobic association of the hydrophobic groups in the PNiPAM chains or a residual interaction between the PNiPAM side chain residues. However, a single endothermic peak does not provide direct evidence for this suggestion.

Noble-metal nanostructures containing gold (Au) nanorods in the center were synthesized by employing Au nanorods as templates for epitaxial growth of silver (Ag). The immediate products, Au@Ag core–shell nanocrystals with an octahedral shape, were transformed into noble-metal (Au, Pd, and Pt) hollow nanostructures containing Au nanorods in the center, via galvanic replacement reactions (see figure).

We present a robust and straightforward method for fabricating remarkably responsive hydrogel scaffolds consisting of submicron-sized microgel particles. We demonstrate that the microgel particles assemble either through bridging or depletion interactions to yield a structure that swells or deswells at a macroscopic level in much shorter times as compared to a bulk polymer gel of similar characteristics. This approach offers a new way of fabricating functional hydrogel scaffolds with controllabl

This paper presents a method for measuring the optical absorption cross-sections (σ(a)) of Au-Ag nanocages and Au nanorods. The method is based on photoacoustic (PA) imaging, where the detected signal is directly proportional to the absorption coefficient (μ(a)) of the nanostructure. For each type of nanostructure, we firstly obtained μ(a) from the PA signal by benchmarking against a linear calibration curve (PA signal vs. μ(a)) derived from a set of methylene blue solutions with different conce

Polymeric core-sheath nanofibers consisting of polymeric sheath and arrays of colloids in the core are produced by one-step single-nozzle electrospinning. Loading different species of active agents in each colloid provides control over the release of each of the agents independently, which enables a programmed release pattern for multiple agents. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or

This article describes a simple method for controlling the assembly of gold nanoparticles (Au NPs) into chainlike structures with tunable lengths and interparticle separations. The chainlike assemblies were induced to form by adding HS(CH(2))(n)COOH (n = 2, 10, and 15) into a suspension of Au NPs in a mixture of ethanol and water (98:2 by volume). The number of Au NPs in the chainlike assemblies could be altered by varying the concentration of the thiol while the interparticle distance between A

See the difference: UV/Vis spectroscopy allows differentiation of the cellular uptakes of gold nanospheres and nanorods from their mixtures by taking advantage of their distinctive optical signatures (see picture).

An approach is presented that permits wide and reversible control of the optical bandwidth of spherical gold nanoparticles assembled on thermoreversible hydrogel colloids for various plasmonic-based thermochromisms. Temperature-dependent swelling and shrinking behaviors of the hydrogel colloids in aqueous systems manipulated assembly structures and optical signals of gold nanoparticles in the hybrid colloids. The optical bandwidths of the hybrid colloids increased with temperature, and thermorev