Progress in the field of optoelectronic integrated chip PCR where Changchun Optoelectronics is located

[ Instrument R & D of Instrument Network ] Humans have been studying nucleic acids for more than 100 years. In the late 1960s and early 1970s, people were devoted to studying the in vitro isolation technology of genes. However, due to the low content of nucleic acids, the in vitro manipulation of DNA is restricted to a certain extent.

It is reported that Khorana proposed the idea of ​​nucleic acid amplification in vitro in 1971. However, the gene sequence analysis method at that time was not yet mature, DNA polymerase with strong heat stability was not found, and the synthesis of oligonucleotide primers was still in the manual and semi-automatic synthesis stage. This idea seems to have no practical significance. .

In 1985, inspired by the highway, American scientist Kary Mullis invented PCR technology after two years of hard work, and published an academic paper on PCR technology in Science magazine. Since then, PCR technology has been widely recognized by the life sciences community.

In addition, as the gold standard for genetic testing, polymerase chain reaction (PCR) technology is an important tool for disease detection. At present, real-time fluorescent PCR (RT-PCR) technology is used as the core method for the clinical detection of many diseases. However, RT-PCR technology also has many shortcomings in terms of sensitivity, detection limit, analysis cost, and the popularization of primary disease control.

Wu Wenming, a researcher at the State Key Laboratory of Applied Optics of the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, took the lead in carrying out polymerase chain reaction technology research at the Changchun Institute of Optics. Recently, the team has combined opto-mechanical integration technology with chip laboratory technology to systematically tackle the shortcomings of traditional RT-PCR technology and made a series of progress.

In view of the shortcomings of traditional RT-PCR technology, such as low sensitivity of nucleic acid detection and low integration automation of traditional digital PCR technology, the team successfully developed a continuous flow, fully automatic, integrated integrated digital PCR system using real-time fluorescence detection mode, which solved The traditional digital PCR system is difficult to distinguish the false positives because of the endpoint detection.

The system is based on a single constant temperature heat source, and only needs one injection to synchronize the entire digital PCR detection process of microdroplet generation, thermal cycle amplification, and nucleic acid absolute quantitative analysis. The workflow is controlled automatically without human operation, which solves the disadvantage of traditional digital PCR systems that rely on manual operation to repeatedly move samples on different instruments.

At the same time, the system comes with solar cells, which can achieve energy self-sufficiency, which lays the foundation for on-site testing, and the cost of the whole laboratory is only less than 10,000 yuan; in terms of testing consumables, it does not rely on the expensive digital PCR used in foreign systems Chip, which greatly reduces the cost of digital PCR detection consumables. Related achievements have been published in multiple SCI journals (Analytica Chimica Acta, 2020, ACA-20-374R2; Sensors 2020, 20, 2492).

The low-cost RT-PCR system successfully developed by the team has achieved real-time fluorescence quantitative analysis of multiple targeted genes including hepatitis B, avian influenza, thyroid factor, measles, and bacillus. Combining chip optical optimization and temperature cycle optimization, the system can also achieve efficient in situ analysis of pathogens.

In response to the shortcomings of Peltier Semiconductor's slow temperature rise and fall, a new RT-PCR quantitative system based on mechanical displacement has been developed. This system can realize a series of functions such as amplification curve detection and melting curve drawing. Compared with TEC, the temperature cycle speed is greatly improved, and the repetitive service life of hardware cycle temperature control is greatly improved, and the volume power consumption and weight of the entire system are reduced. At the same time, it lays the foundation for rapid thermal cycle PCR technology.

In order to solve the shortcomings of PCR chip fluid control relying on expensive external drive systems, the team systematically carried out the research of "external energy-free and complex drive system" multi-phase fluid spontaneous control, and extended a variety of derivative principles from the methodological level A variety of spontaneous fluid control methods and new chip designs have realized different downstream applications in the chip laboratory, and based on continuous flow technology, the "Handheld Gene Fingerprint Analyzer" and the "Handheld Real-Time "Fluorescence quantitative PCR system" lays the foundation for on-site detection.

As a technology widely used in the field of disease detection, nucleic acid detection PCR still has high detection costs, which will bring huge pressure to the popularization of detection and the national economy. Therefore, reducing the cost of PCR testing is of great significance to the prevention and control of various infectious diseases. To achieve the above goals, it is still necessary to carry out in-depth systematic breakthrough research on analytical instruments and detection reagents, which will also be the team ’s next step. Focus of work.