Kang-Tae Lee

A track record: Upconverting nanoparticles (UCNPs) were tracked in living HeLa cells and their active transport by motor proteins was visualized in real time. The remarkable photostability of the UCNPs and the noninvasiveness of near-infrared excitation allowed continuous observation of living cells for as long as 6 h. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made avail

L-phenylalanine (Phe), one of the aromatic amino acids, and its hydrated clusters were generated in supersonic expansion and investigated by resonant two-photon ionization. Excitation spectra of Phe and Phe–(H2O)1 were obtained near their S0–S1 origins. We found that, by comparing the experimental results with the density functional theory and ab initio calculations, the water in Phe–(H2O)1 tends to form a cyclic hydrogen bond at the carboxyl group while inducing little change in the correspondi

Due to the unique properties of lanthanide-doped upconverting nanoparticles (UCNP) under near-infrared (NIR) light, the last decade has shown a sharp progress in their biomedicine applications. Advances in the techniques for polymer, dye, and bio-molecule conjugation on the surface of the nanoparticles has further expanded their dynamic opportunities for optogenetics, oncotherapy and bioimaging. In this account, considering the primary benefits such as the absence of photobleaching, photoblinkin

As much as 8 kcal mol−1 separates the ionization energies of the lowest energy conformers of L-phenylalanine. This conformation-dependent energy difference, by far the largest reported to date for any molecule, is associated with the drastic change in hydrogen bonding upon ionization (see picture).

Lanthanide-doped upconverting nanoparticles (UCNPs, NaYF4:Yb(3+),Er(3+)) are well known for emitting visible photons upon absorption of two or more near-infrared (NIR) photons through energy transfer from the sensitizer (Yb(3+)) to the activator (Er(3+)). Of the visible emission bands (two green and one red band), it has been suggested that the red emission results from two competing upconversion pathways where the non-radiative relaxation occurs after the second energy transfer (pathway A, (4)I

Hinterher! Aufwärtskonvertierende Nanopartikel (UCNPs) wurden in lebenden HeLa-Zellen verfolgt, und ihr aktiver Transport durch Motorproteine wurde in Echtzeit abgebildet. Die beachtliche Photostabilität der UCNPs und die unschädliche Anregung im nahen Infrarot ermöglichten die kontinuierliche Beobachtung lebender Zellen über einen Zeitraum von bis zu sechs Stunden.

Upconverting nanoparticles (UCNPs) have been studied as novel bioimaging probes owing to the absence of autofluorescence and excellent photostability. For practical applications, biocompatible UCNPs with high upconversion efficiency, bright luminescence, and good colloidal stability are desirable. Herein, we report a quantitative and systematic study on the upconversion luminescence from a set of NaYF 4:Yb 3+,Er 3+ -based nanoparticles by varying crystal structures, core/shell structures, and su

could be modulated by emission depletion (ED) of the intermediate state that interacts resonantly with an infrared beam (1540 nm). In contrast, the green emission bands (525 and 545 nm) of the UCNPs were less affected by irradiation with the infrared beam. The origin of such distinct behaviors between the green and red emissions was attributed to their different photophysical pathways.

FITC-conjugated core–shell–shell upconverting nanoparticles as pH-responsive nanoprobes.

We report on the development of a three-dimensional (3D) live-cell imaging technique with high spatiotemporal resolution using lanthanide-doped upconverting nanoparticles (UCNPs). It employs the sectioning capability of confocal microscopy except that the two-dimensional (2D) section images are acquired by wide-field epi-fluorescence microscopy. Although epi-fluorescence images are contaminated with the out-of-focus background in general, the near-infrared (NIR) excitation used for the excitatio