유준화 교수

Though creation and characterization of water soluble luminescent silver nanodots were achieved only in the past decade, a large variety of emitters in diverse scaffolds have been reported. Photophysical properties approach those of semiconductor quantum dots, but relatively small sizes are retained. Because of these properties, silver nanodots are finding ever-expanding roles as probes and biolabels. In this critical review we revisit the studies on silver nanodots in inert environments and in

Every nucleolus has a silver lining: Formation of silver nanoclusters by fluorescence photoactivation was used for the staining of cells at low silver nitrate concentrations and ambient temperature. The picture shows picosecond lifetime images of peptide-encapsulated silver nanoclusters within NIH 3T3 cells. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z604253_s.pdf or from the author. Please note: The publisher is not respon

Clustering together: A shuttle-based fluorogenic cluster transfer, in which silver clusters (SCs) are directly transferred from a low-molecular-weight poly(acrylic acid) (PA) shuttle to a single-stranded DNA (ssDNA) tag on the protein of interest (see picture), proceeds with excellent specificity. Upon transfer, the cluster fluorescence increases more than ten times, which provides bright, photostable labeling. Detailed facts of importance to specialist readers are published as ”Supporting Infor

A europium complex selectively staining the nucleolus of NIH 3T3, HeLa, and HDF cells is reported. This complex possesses not only the advantage of the long lifetime of europium emission (0.3 ms), but also a chromophore that allows excitation at a relatively long wavelength (lambda(max) = 384 nm) and gives rise to an acceptable quantum yield (9%). The complex can be used both in live cell and fixed cell imaging, giving an average intracellular concentration on the order of 0.5 microM. Strong bin

DNA-encapsulated silver clusters are readily conjugated to proteins and serve as alternatives to organic dyes and semiconductor quantum dots. Stable and bright on the bulk and single molecule levels, Ag nanocluster fluorescence is readily observed when staining live cell surfaces. Being significantly brighter and more photostable than organics and much smaller than quantum dots with a single point of attachment, these nanomaterials offer promising new approaches for bulk and single molecule biol

Recently, various studies related to the photophysical properties of various nanoscale and subnanoscale particles have been actively carried out in the chemical and biological fields. However, the terminology of these nanoparticles has not been clearly defined, which causes confusion among research groups and students. This article aims to clarify the definitions of four terms: quantum dots (QDs), nanodots (NDs), nanoclusters (NCs), and clusters. The historical usage of these terms and research

Glutaraldehyde causes especially high autofluorescence. It reacted with proteins and peptides to generate visible to near-IR emitters. A model indicated that ethylenediamine and a secondary amine in the molecule were key components for the formation of emissive species. The mechanism enables us to control the generation and elimination of autofluorescence.

Nucleoli mit Silberstreifen: Die Bildung von Silbernanoclustern durch Fluoreszenz-Photoaktivierung wurde für das Anfärben von Zellen bei niedriger Silbernitratkonzentration und Raumtemperatur genutzt. Das Bild zeigt Bildung und Zerfall von in Peptiden eingeschlossenen Silbernanoclustern in NIH 3T3-Zellen.

The electron spin resonance spectrum of superoxide anion radical adsorbed on the surface of colloidal TiO2 was detected directly at room temperature for the first time. This signal was generated partially by porphyrin-sensitized titanium dioxide, i.e., the reduction of adsorbed oxygen on the TiO2 nanocluster surface by the just injected electron from the excited porphyrin.

Leuchtender Cluster: Die direkte Übertragung fluorogener Silbercluster (SCs) von einer niedermolekularen Polyacrylsäure (PA) als Shuttle auf Einzelstrang-DNA(ssDNA)-Markierungen auf dem interessierenden Protein (siehe Bild) verläuft hochspezifisch. Bei der Übertragung nimmt die Clusterfluoreszenz um mehr als das Zehnfache zu, was ein helles, photostabiles Markieren ermöglicht. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-re

Reactive oxygen species selectively accelerated transitions between various silver nanodots. The blue was developed as an oxidant-resistant imaging agent and analyte reporter. In addition to the spectral response of nanodots to ROS, silver nanodots were formulated to detect analytes with excellent selectivity and picomolar detection limit when coupled to glucose oxidase.

Abstract A regioselective synthetic route that allows the construction of tri‐functionally substituted cyclen is described. This facilitates the synthesis of a europium complex that exhibits a good photoresponse to malate, forming the basis of a chemoselective sensor. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

The etching mechanism of silver nanoparticles was investigated. Though a strong binding agent to silver and an oxidising agent synergistically etch the nanoparticles, the balanced etching power has to be optimized to generate luminescent silver nanodots. This indicates that active centres facilitate the formation of nanodots.

A water-insoluble porphyrin derivative was studied in Triton X-100 micelles by steady-state spectroscopy and picosecond photolysis. The porphyrin in micelles formed J aggregates, and, consequently, the excited-state lifetime of such a porphyrin was very short. After the addition of colloidal SiO2, the B-band absorption blue-shifted, forming a broad absorption peak. This peak can be ascribed to the monomer-dominated absorption of porphyrin. The photolysis experiment showed that the dynamic curve