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Biomedical subjects

William W Yu

Publications and source records attributed to William W Yu.

6 recordsLinked to original sources
PubMed2006

Low-field magnetic separation of monodisperse Fe3O4 nanocrystals.

Magnetic separations at very low magnetic field gradients (<100 tesla per meter) can now be applied to diverse problems, such as point-of-use water purification and the simultaneous separation of complex mixtures. High-surface area and monodisperse magnetite (Fe3O4) nanocrystals (NCs) were shown to respond to low fields in a size-dependent fashion. The particles apparently do not act independently in the separation but rather reversibly aggregate through the resulting high-field gradients present at their surfaces. Using the high specific surface area of Fe3O4 NCs that were 12 nanometers in diameter, we reduced the mass of waste associated with arsenic removal from water by orders of magnitude. Additionally, the size dependence of magnetic separation permitted mixtures of 4- and 12-nanometer-sized Fe3O4 NCs to be separated by the application of different magnetic fields.

Journal Article↗
PubMed2006

Water-soluble quantum dots for biomedical applications.

Semiconductor nanocrystals are 1-10nm inorganic particles with unique size-dependent optical and electrical properties due to quantum confinement (so they are also called quantum dots). Quantum dots are new types of fluorescent materials for biological labeling with high quantum efficiency, long-term photostability, narrow emission, and continuous absorption spectra. Here, we discuss the recent development in making water-soluble quantum dots and related cytotoxicity for biomedical applications.

Animals↗
PubMed2005

Protease-activated quantum dot probes.

We have developed a novel nanoparticulate luminescent probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This construct may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Release of AuNPs by peptide cleavage restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 h of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker.

Coated Materials, Biocompatible↗
PubMed2002

SM22beta encodes a lineage-restricted cytoskeletal protein with a unique developmentally regulated pattern of expression.

Cytoskeletal proteins play important roles in regulating cellular morphology, cytokinesis and intracellular signaling. In this report, we describe a developmentally regulated gene encoding a novel cell lineage-restricted cytoskeletal protein, designated SM22beta. SM22beta shares high-grade sequence identity with the smooth muscle cell (SMC)-specific protein, SM22alpha, the neuron-specific protein, NP25, and the Drosophila melanogaster flight muscle-specific protein, mp20. The mouse SM22beta cDNA encodes a 199-amino acid polypeptide that contains a single conserved calponin-like repeat domain. During mouse embryonic development, the SM22beta gene is expressed in a temporally and spatially regulated pattern in the tunica media of arteries and veins, endocardium and compact layer of the myocardium, bronchial epithelium and mesenchyme of the lung, gastrointestinal epithelium and cartilaginous primordia. During postnatal development, SM22beta is co-expressed with SM22alpha in arterial and venous SMCs. In addition, SM22beta is expressed at high levels in the bronchial epithelium and lung mesenchyme, gastrointestinal epithelial cells and in the cartilagenous and periosteal layer of bones. Three-dimensional deconvolution microscopic analyses of A7r5 SMCs revealed that SM22beta co-localizes with SM22alpha to cytoskeletal actin filaments. Taken together, these data demonstrate that SM22beta is a novel actin-associated protein with a unique cell lineage-restricted pattern of expression.

3T3 Cells↗