Objective According to principle of forming primer dimer,a new cloning gene method was established. Methods Two and more oligonucleotide with complementary partnership in the 3′ end were synthesized by artifical method,oligonucleotide,Taq DNA polymerase and dNTP were mixed in the proportion of reasonable,then expanded and extended by PCR,result was identifed by agarose gel electrophoresis.Results A clear special band was appeared in the agarose gel. Conclusion Short fragment target gene less than 500 bp may be synthesized by this method.

In order to construct a new type of piezoelectric quartz immunosensor for the determination of carcino-embryonic antigen (CEA), the sensor detection pools were consisted of plastic loops and crystals that were 10 MHz quartz AT-cut with gold coated electrodes and the immobilization of the monoclonal antibody against CEA onto gold electrode surface of the quartz crystal was accomplished via Thiol method. Then the immunosensors were used in clinical laboratory. The experimental results showed that the piezoelectric immunosensor had good response to CEA, the frequency shifts were linearly dependent on CEA concentration in the range of 1.56 to approximately 50.00 ng/ml, other antigens such as alpha fetoprotein (AFP), prostate specific antigen (PSA), human chorionic gonadotropin (hCG) did not interfere with the sensor's response. The results obtained from this method were in satisfactory accordance with those obtained by radio immunoassay(P>0.05), The correlation coefficient was 0.90. Piezoelectric immunosensor for determination of CEA has the advantage of high sensitivity, high specificity, unnecessary labeling, simple performing, rapid analysis, low cost, real-time detection and repeated use, etc. It can be used for detecting serum CEA in clinical laboratory.
Antibodies, Monoclonal ; Carcinoembryonic Antigen ; blood ; immunology ; Electrodes ; Equipment Design ; Humans ; Immunoassay ; instrumentation ; methods ; Quartz ; Sensitivity and Specificity