The world's first instrument, Zhang Jiang, came out with a small amount of cancer cells

Targeted therapies and personalized medicine are being promoted in the medical world. To carry out such "gene therapy", it is essential for the sequencing of human genes. The reporter learned yesterday that the world's first liquid-phase fixed-point gene sequencer was introduced in the Zhangjiang Hi-Tech Park. This instrument can detect genetic variation in samples with a cancer cell ratio of less than 20%, and the gene sequencing technology currently used in hospitals. All require that the number of cancer cells be no less than 40%. Experts from the Shanghai National Engineering Research Center for Biochips stated that this invention has broad prospects for medical applications.

According to Huang Xinhua, a researcher and developer, gene sequencing is a key technology for the human genome project. It is known as the "gold standard" for genetic testing. General gene sequencing includes three steps: PCR amplification, replication and amplification of the DNA to be detected, sequencing reactions using the "terminal termination method" of the Nobel Prize, and capillary electrophoresis of the completed gene sequence, followed by detection of DNA. The fluorescence signal, you can obtain the "password" of the gene sequence.

After years of research, Huang Xinhua found that the third step of "gold standard" method "capillary electrophoresis" is not necessary in sequencing specific gene loci. If the reverse signal of the fluorescent signal, the quenching signal, is detected in the second step "end termination method" of the liquid sequencing reaction, the genetic code can be decrypted and the gene sequence can be passed through the capillary for up to about 10 hours without the need for the gene sequence to pass through the capillary. Sequencing. Based on this innovative idea, Huang Xinhua led the team to invent a new type of instrument—a liquid-phase fixed-point gene sequencer and applied for a national invention patent.

Compared with conventional gene sequencers, this instrument greatly shortens the time for gene sequencing, from the original dozen hours to several hours; the cost of its sequencing is also greatly reduced, only 1/3 of the current sequencer. Moreover, its sequencing sensitivity has improved. When hospitals detect DNA mutations in tumor samples, they usually require that the proportion of cancer cells in the tumor sample be no less than 40%. Otherwise, the test results may be "false negative." This instrument will detect DNA variation when the cancer cell ratio is less than 20%.

For this achievement, Zhang Qinghua, a researcher at the Shanghai National Engineering Research Center for Biochips, stated that it has a good application prospect in medical institutions and is suitable for genetic diagnosis of major diseases such as cancer and diabetes, providing accurate targeted therapy and personalized medicine. Gene sequencing report. It is worth mentioning that genetic sequencing devices and key reagents have always been monopolized by U.S. companies, and the advent of liquid-phase fixed-point sequencing devices is expected to break this monopoly.