THE NEW CORONAVIRUS NUCLEIC TEST IS WIDELY USED IN HOSPITALS, BUT IT USUALLY TAKES SEVERAL HOURS TO GET RESULTS. Recently, the Fudan University team proposed a "molecular electromechanical system" that can directly detect the new coronavirus in nasopharyngeal swab samples, and the detection time is less than 4 minutes.
The paper was published in a screenshot of the Natural Biomedical Engineering website
Recently, the Department of Polymer Sciences of Fudan University, the State Key Laboratory of Polymer Molecular Engineering Wei Dacheng Research Group and collaborators developed a transistor sensing chip based on "Molecular Electromechanical System" (MolEMS), which is based on "Rapid and ultrasensitive electromechanical detection of ions, biomolecules and new coronavirus RNA in unamplified samples". Biomolecules and SARS-CoV-2 RNA in unamplified samples) are published in Nature Biomedical Engineering.
On February 11, the surging news (www.thepaper.cn) reporter learned from the research group that the advantages of the new equipment are rapid detection, ultra-high sensitivity, small and portable devices, and no need for other professional equipment.
(a) Schematic diagram of micro/nano electromechanical systems; (b) schematic diagram of molecular electromechanical systems; (c-e) transistor sensor and chip picture based on molecular electromechanical system; (g-f) confocal fluorescence microscopy and atomic force microscopy characterization picture of sensing chip. Fudan University official website map
Wei Dacheng's research group has long been committed to the research of new transistor materials, devices and their applications in the fields of biology, chemistry and optoelectronic sensing. They proposed the "Molecular Electromechanical System" (MolEMS), a miniature device that is self-assembled by DNA molecules and driven by an external electric field to accurately regulate molecular recognition and signal transformation processes.
By assembling the molecular electromechanical system onto a graphene field-effect transistor, its rigid base helps to avoid non-specific adsorption of contaminants, and the external electric field drives the flexible adapter cantilever to move, bringing the sensing process closer to the transistor channel, significantly improving sensitivity. Ultra-sensitive detection of metal ions (Hg2+), proteins (Thrombin), biological small molecules (ATP), and new coronavirus nucleic acids (RNA and cDNA) is achieved in buffer solutions or biological liquids.
Detecting NEW CORONAVIRUS nucleic acid samples does not require a complex and time-consuming nucleic acid extraction and amplification process, with a minimum detection limit of 10-20 copies per milliliter and a detection time of less than 4 minutes, which is better than existing COVID-19 nucleic acid PCR detection methods.
The State Key Laboratory of Polymer Molecular Engineering and the Department of Polymer Science of Fudan University were the first and second units of the paper, respectively; Wei Dacheng of Fudan University presided over the research project; Dr. Wang Liqian, Ph.D. Wang Xuejun, Ph.D. student Wu Yungen and Ph.D. Guo Mingquan of Fudan University were co-first authors; Academician Liu Yunxi, Professor Xie Youhua, and Academician Fan Chunhai of Shanghai Jiao Tong University participated in the research.
Nucleic acid detection, antibody detection, antigen detection have their own characteristics, at present, there are many new crown rapid detection reagent products at home and abroad.
Researcher and doctoral supervisor Wei Dacheng said that the rapid detection reagents are mostly antigen detection based on colloidal gold method, which is not as accurate as nucleic acid detection. At present, the rapid detection reagents on the market are prone to "missed tests", and the widespread use of nucleic acid testing for viruses in domestic laboratories is still widely used.
He said that the principle of "molecular electromechanical systems" is different from nucleic acid PCR detection. In PCR detection, a fluorescence signal is used to report whether a sample is positive. Obtaining a fluorescent signal of sufficient intensity requires amplification of nucleic acids, and the amplification process often takes one to two hours.
However, when applying new detection equipment, the detection of new coronavirus nucleic acid samples does not require a complex and time-consuming nucleic acid extraction and amplification process. Transistors in a device can be very small. The conductive channel inside the transistor is a semiconductor, which converts the chemical signal into an electrical signal on the one hand, and can amplify the signal on the other hand. By analyzing the electrical signal, the detection results can be obtained.
"The detection device is not only used for the detection of the new crown virus, it is actually a platform that can detect a variety of viruses, including influenza viruses and new coronaviruses, by replacing sensors." Wei Dacheng said that he hopes that this general technology can be widely popularized in the future, not only targeting the new crown virus, but also helping other virus detection, which is also the goal pursued by the team.
At present, this detection device is in the application research and development stage. In order to achieve large-scale clinical application of the device, it is also necessary to solve some technical problems and reach higher standards.
For example, Wei Dacheng explained that the equipment must not only be able to operate in a laboratory environment, but also work normally in places with low or high temperatures; measure dozens to hundreds of samples accurately in the laboratory, and if it is really applied, it is necessary to measure more samples without deviation; it also needs a standardized production process to ensure that the performance of the chips produced is completely consistent.
How far is this device from practical application? Wei Dacheng said that the work of the research group has verified the feasibility of the technical principle. At present, the team is working with enterprises to realize the industrialization of technology.