Biomedical subjects

Xiao-Feng Hua

Publications and source records attributed to Xiao-Feng Hua.

3 recordsLinked to original sources

PubMed2006

Preparation of Au coated polystyrene beads and their application in an immunoassay.

A novel immunoassay method based on polystyrene beads coated with Au nanoparticles (Au@PS) is described. Au nanoparticles were prepared by reductive reaction, and then deposited on the surface of polystyrene beads to form Au coatings. Results indicated that the Au coatings had good stability and that human IgG was immobilized at a concentration of 16 microg/g Au@PS. FITC-labeled rabbit-anti-human IgG and FITC-labeled rabbit-anti-goat IgG were employed to react with the human IgG on Au@PS. Fluorescence imaging results showed that the reaction had good immuno-specificity. In addition, further experiments at the single-bead level indicated that the linear range was 0.05-15 microg/ml, and that the FITC signal could be detected even when the target antibody concentration was as low as 0.01 microg/ml. The assay results were compared with an enzyme-linked immunosorbent assay (ELISA), and showed relatively good reliability.

Animals↗

PubMed2006

Characterization of the coupling of quantum dots and immunoglobulin antibodies.

Water-soluble quantum dots (QDs) were used to label goat anti-human immunoglobulin antibodies (Abs), and the labeling process was characterized by column purification. The QDs obtained in organic solvent were modified with mercaptoacetic acid (MAA) and became water-soluble. These water-soluble QDs were linked to the antibodies using the coupling reagents ethyl-3-(dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The linking process was shown to be effective by ultra-filter centrifugation and column purification. After comparing the quantities of Abs and water-soluble QDs involved in the linking reaction via column purification, it was found that a molar Abs:QD ratio of >1.2 resulted in most of the water-soluble QDs becoming covalently linked to the Abs. The circular dichroism (CD) spectra of Abs and QD-Ab conjugates were very similar to each other, indicating that the secondary structure of Abs remained largely intact after the conjugation. Finally, antigen (Ag)-antibody (Ab) recognition reactions perfomed on the surface of a glass slide showed that the conjugate retained the activity of Abs. This work lends support to the idea of linking biomolecules to QDs, and thus should aid the application of QDs to the life sciences.

Humans↗

PubMedDate not supplied

Quantum dot optical encoded polystyrene beads for DNA detection.

A novel multiplex analysis technology based on quantum dot (QD) optical encoded beads was studied. Carboxyl functionalized polystyrene beads, about 100 microm in size, were precisely encoded by the various ratios of two types of QDs whose emission wavelengths are 576 and 628 nm, respectively. Then the different encoded beads were covalently immobilized with different probes in the existing of sulfo-NHS and 1-[3-(Dimethylamino) propyl]-3-ethylcarbodiimide methiodide, and the probe density could reach to 3.1 mmol/g. These probe-linked encoded beads were used to detect the target DNA sequences in complex DNA solution by hybridization. Hybridization was visualized using fluorescein isothiocynate-labeled DNA sequences. The results show that the QDs and target signals can be obviously identified from a single-bead-level spectrum. This technology can detect DNA targets effectively with a detection limit of 0.2 microg/mL in complex solution.

Base Sequence↗