Biomedical subjects

Jianxin Tang

Publications and source records attributed to Jianxin Tang.

4 recordsLinked to original sources

PubMed2006

Time-resolved fluorescence detection of mosaic DNA chip.

We demonstrated a time-resolved fluorescence (TRF) label and detection of mosaic DNA chip in this paper. We synthesized oligonucleotide sequences in situ on glass slides directly, and then sliced them up into small pieces and patched up the pieces bearing different sequences to generate a mosaic DNA chip. With multiple 4, 7-bis(chlorosulfophenyl)-1, 10-phenanthroline-2, 9-dicarboxylic acid (BCPDA, abbreviated as BCPDA) labeling method based on avidin-biotin amplification, we established a TRF detection format on the mosaic DNA chip. The detection method allows discriminatory signals for perfect match, one-base mismatch, two-base mismatch, and three-base mismatch by TRF labeled DNA hybridization, whereby Europium (III, Eu3+) was captured and released on the principle of complexation and dissociation interaction between BCPDA and Eu3+ solution when the BCPDA-tagged avidin and biotin-capped oligonucleotide sequence linked. The fluorescence spectra and related lifetimes were determined. We also compared the TRF detection mode with the conventional fluorescence one. These results showed the former is a potential alternative replacement of the latter, especially for labeling the mosaic DNA chip. The discovery is of fundamental interest and has significant implications to biochips and biosensors based on time-resolved-fluorescence detection.

Avidin↗

PubMed2005

Synthesis and hybridization studies of DNA on functionalized polypropylene surfaces.

Polypropylene (PP) slice was treated with plasma in a mixture of nitrogen and hydrogen (1:2 V/V). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the successful grafting of amino groups. The as-treated slices were successively applied to the in-situ synthesis of oligonucleotides and an average coupling yield of more than 98% was achieved. The hybridization signals were recorded with fluorescent analysis system. The complementary and mismatched sequences were distinguished clearly, and the ratio of fluorescence intensity values (arbitrary units) for perfect match:single base mismatch:two bases mismatch:three bases mismatch is 108.6: 62.9: 22.4: 5.5. The results implied the plasmamodified PP surface was extremely stable, performed well in DNA hybridization assays, and could service as a good substrate for high-density oligonucleotide array synthesis, especially in a multistep molecular stamping method to fabricate DNA microarrays in-situ on a large scale.

DNA Probes↗

PubMed2005

[A gene-chip image grid localization method based on profiles of image].

Automatic gene-chip image grid localization is an essential task for gene-chip image analysis. Now an method based on profiles of gene-chip image is proposed. Using the differences between two profiles after filtration by arithmetic mean method, we can easily find the local grayscale minimum between two probe spots, then the probe spots are automatically located. The experiments show that the new approach correctly locates the probes while giving protection against noise affection robustly. Grid location

Algorithms↗

PubMed2004

Colorimetric detection of polynucleotides on polypropylene slices.

The gold-label-silver-stain method (GLSS) for DNA hybridization detection has been receiving increased interest as a colorimetric detective method, demonstrating the advantages of non-radioactivity, non-quenching effect of fluorescence and simplicity for analytical equipment. A colorimetric detection based on the GLSS method was applied to DNA arrays in situ synthesized on polypropylene (PP) slices. In this paper a simple plasma treatment was employed to graft amino (-NH2) on the polypropylene slice surfaces, where DNA probes were immobilized via in situ synthesis. Hybridization was accomplished by a sandwich hybridization format. With the amplification of Silver Enhancer Solution, the hybridization signals were recorded with a scanner. A target DNA concentration as low as 100 fM was detected. Complementary and mismatched sequences were clearly distinguished, and the ratio of the background-subtracted gray scale values for a perfect match, single-base mismatch, 2-base mismatch and 3-base mismatch is 22:16:9:4. The sensitivity of the in situ synthesis system was 3 orders of magnitude higher than that of the spotting system, and the signals of the former were about 2-times stronger than that of the latter under the same target DNA concentration.

Colorimetry↗