Yi Xiao

Isomeric boron-fluorine complexes with donor-acceptor architecture: strong solid/liquid fluorescence and large Stokes shift.

Novel isomeric fluorine-boron complexes with donor-acceptor architecture have been efficiently synthesized and well characterized. Significant features, such as strong solid and liquid fluorescence, unusual large Stokes shifts, and lower LUMO levels and higher HOMO levels, are observed in these potential multifunctional molecules.

Versatile Nitro-Fluorophore as Highly Effective Sensor for Hypoxic Tumor Cells: Design, Imaging and Evaluation

AbstractBased on the characteristics of a nitro-group, which can be partially or totally reduced to an amino-group in hypoxic cells, two series of hypoxic sensors containing 7H-Benzimidazole [2,1-a]benz[de]isoquinolin-7-one cores with nitro groups in different positions were designed, synthesized and evaluated. The target compounds exhibited significantly different fluorescence characteristics (fluorescence enhancement or quenching). The strong fluorescences of some partially reduced compounds could be explained through the examination of their infrared spectra, which showed a restriction of the nitro-group vibration. These compounds exhibited significant hypoxic–oxic fluorescence differences not only in numerical values but also in their fluorescent imaging properties as reported for the first time.n

Novel angular furoquinolinones bearing flexible chain as antitumor agent: Design, synthesis, cytotoxic evaluation, and DNA-binding studies

A series of novel N-substituted angular furoquinolinone derivatives were synthesized and evaluated for their antitumor activities against QGY, K562, HeLa, P388, and A549 cell lines in vitro. The derivatives bearing basic amino side chain showed an improved antitumor activity. Compound 5h N-(2-dimethylamino-ethyl)-2-(4,8,9-trimethyl-2-oxo-2H-furo[2,3-h]quinolin-1-yl)-acetamide exhibited the highest activities against P388 and A549 cell lines, which are evidenced by the IC(50) values that are four to five fold lower than that for unsubstituted parent compound. DNA-binding experiments suggested that these derivatives bind to DNA through intercalation.

Highly chemoselective reduction of aromatic nitro compounds to the corresponding hydroxylamines catalysed by plant cells from a grape (Vitis vinifera L.)

Cells from a grape (Vitis vinifera L.) reduce aromatic nitro compounds under mild conditions to the corresponding hydroxylamines with unprecedented chemoselectivity.

Super-Resolution Monitoring of Mitochondrial Dynamics upon Time-Gated Photo-Triggered Release of Nitric Oxide

Nitric oxide (NO) potentially plays a regulatory role in mitochondrial fusion and fission, which are vital to cell survival and implicated in health, disease, and aging. Molecular tools facilitating the study of the relationship between NO and mitochondrial dynamics are in need. We have recently developed a novel NO donor (NOD550). Upon photoactivation, NOD550 decomposes to release two NO molecules and a fluorophore. The NO release could be spatially mapped with subdiffraction resolution and with a temporal resolution of 10 s. Due to the preferential localization of NOD550 at mitochondria, morphology and dynamics of mitochondria could be monitored upon NO release from NOD550.

Highly Sensitive Hill-Type Small-Molecule pH Probe That Recognizes the Reversed pH Gradient of Cancer Cells

A hallmark of cancer cells is a reversed transmembrane pH gradient, which could be exploited for robust and convenient intraoperative histopathological analysis. However, pathologically relevant pH changes are not significant enough for sensitive detection by conventional Henderson-Hasselbalch-type pH probes, exhibiting an acid-base transition width of 2 pH units. This challenge could potentially be addressed by a pH probe with a reduced acid-base transition width (i.e., Hill-type probe), appropriate p Ka, and membrane permeability. Yet, a guideline to allow rational design of such small-molecule Hill-type pH probes is still lacking. We have devised a novel molecular mechanism, enabled sequential protonation with high positive homotropic cooperativity, and synthesized small-molecule pH probes (PHX1-3) with acid-base transition ranges of ca. 1 pH unit. Notably, PHX2 has a p Ka of 6.9, matching the extracellular pH of cancer cells. Also, PHX2 is readily permeable to cell membrane and allowed direct mapping of both intra- and extracellular pH, hence the transmembrane pH gradient. PHX2 was successfully used for rapid and high-contrast distinction of fresh unprocessed biopsies of cancer cells from normal cells and therefore has broad potentials for intraoperative analysis of cancer surgery.