Biomedical subjects

Xingguang Su

Publications and source records attributed to Xingguang Su.

5 recordsLinked to original sources

PubMed2004

Methods for labeling quantum dots to biomolecules.

Semiconductor quantum dots (QDs) are thought to be the most promising fluorescent probe for biological and biomedical applications because of their unique size-dependent optical and electronic properties. QD bioconjugates provide important advantages over conventional organic dyes. This review compares the optical properties of nanoparticles and dyes and describes the surface modification of the QDs and the methods for biomolecules conjugating to QDs. In addition, the effect of QDs on normal physiology in real biological applications is discussed.

Fluorescent Dyes↗

PubMed2003

Studies on quantum dots synthesized in aqueous solution for biological labeling via electrostatic interaction.

3-Mercaptopropyl acid-stabilized CdTe nanoparticles synthesized in aqueous solution are effectively bound to a biomacromolecule, papain, via electrostatic interaction. The conjugation between the nanoparticles and the papain is demonstrated by UV-Vis absorption, photoluminescence spectroscopy, transmission electron microscopy, and fluorescence micrographs. The biological activity of papain is maintained after the conjugation. The effects of the quantity of papain and the size of nanoparticles on the fluorescence characteristics of the CdTe-papain bioconjugates were studied.

Biotechnology↗

PubMedDate not supplied

Studies on fluorescence resonance energy transfer between dyes and water-soluble quantum dots.

In this work, donor-acceptor complexes were formed based on antibody-antigen interactions. Immunoglobulin antigen (mouse-IgG) was effectively conjugated to mercaptopropyl acid-modified CdTe quantum dot synthesized in aqueous solution via electrostatic interaction, while organic dyes-tetramethylrhodamine isothiocyanate (TRITC) were attached to the corresponding antibody (anti-mouse IgG). The mutual affinity of the antigen and antibody brought the CdTe quantum dot and TRITC sufficiently close together to allow the resonance dipole-dipole coupling required for fluorescence resonance energy transfer to occur. The formation of immunocomplexes resulted in fluorescence resonance energy transfer from the CdTe quantum dot donors to the TRITC acceptors.

Animals↗

PubMedDate not supplied

The preparation of CdTe nanoparticles and CdTe nanoparticle-labelled microspheres for biological applications.

Different sizes of CdTe semiconductor nanoparticles were prepared in aqueous solution. These nanoparticles exhibit narrow fluorescence with full width at half-maximum (FWHM) of 35-45 nm that spans the visible spectrum, and they also have high PL quantum yield with high resistance to photodegradation. In addition, CdTe quantum dot (QD)-labelled microspheres, comprising polystyrene (PS) cores and CdTe/polyelectrolyte (PE) shells, were also prepared by the layer-by-layer technique in this paper. The optical properties of the CdTe nanoparticles and CdTe-labelled microspheres were investigated by UV-Visible absorption and luminescence spectroscopy, and fluorescence microscopy was employed for microscopic identification behaviour of the luminescent microspheres.

Animals↗

PubMedDate not supplied

Fluorescence resonance energy transfer between two quantum dots with immunocomplexes of antigen and antibody as a bridge.

In this study, 573 nm quantum dots (QDs)-rabbit IgG-goat anti-rabbit IgG-638 nm QDs immunocomplexes were prepared, utilizing antigen-antibody interaction. 573 nm-emitting QDs were conjugated to antigen (rabbit IgG) and 638 nm-emitting QDs were conjugated to antibody (goat anti-rabbit IgG) via electrostatic/hydrophilic self-assembly, respectively. The mutual affinity of the antigen and antibody brought two kinds of QDs close enough to result in fluorescence resonance energy transfer (FRET) between them; the luminescence emission of 573 nm QDs was quenched, while that of 638 nm QDs was enhanced. The luminescence emission of 573 nm QDs could be recovered when the immunocomplexes were exposed to the unlabelled rabbit IgG antigen. The FRET efficiency (E) and the distance between the donor and the acceptor were calculated.

Absorption↗