| In this paper, the ICP-MS detection analysis method was developed including the gold nanoparticles modified with a capture biological barcode probe, the technology of DNA molecular machines and enzymatic cycling, the specific recognition between target DNA and molecular beacons. This method was used to detect genes and tumor markers; Total internal reflection fluorescence microscope (TIRF) was used to achieve the target gene detection via obtaining the fluorescence image of a single target DNA, which was enlarged by rolling circle amplification (RCA). The main content was described as follows:(1) In the present study, an inductively-coupled plasma-mass spectrometry (ICP-MS)-based triple-amplification system, by combination of nicking-displacement, rolling circle amplification (RCA) and bio-bar-code probes, was fabricated for the detection of DNA target. By using this system, hepatitis B virus (HBV) DNA target down to 3.2×10-17 M was detected by DNA probes labeled with Au nanoparticles (AuNPs). Single nucleotide polymorphisms in genes can also be effectively discriminated. In addition, we proved that this strategy is capable of detecting the target in complicated biological samples and holds great potential application in biomedical research.(2)TIRF(total internal reflection fluorescence microscope), which is a relatively complex optical technology, has now been widely used by scientists. It has become the most powerful method to detect the cellular life activity in the cell basement contact region. In this experiment, the RCA target DNA was fixed on a glass plate. Then, the target DNA was stretched as a line by using optical tweezers moving the polystyrene microspheres which was modified at the end of the molecule. Next, the target DNA chain was hybridized with its complementary fluorescent DNA. Finally, TIRF was used to observe the base of the glass plate. As a new technology of single molecule imaging, TIRF will certainly help us to detect tumor markers. |
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